Physics Views

2011-12-07T12:17:00.001-08:00

Photoelectric effect

Grecia S. Laboy

The photoelectric effect is the emission of electrons from a metal when you affect it electromagnetic radiation (visible light or ultraviolet light, in general). Sometimes the term is included in other types of interaction between light and matter. The photoelectric effect was discovered and described by Heinrich Hertz in 1887, noting that the arc jumps between two electrodes connected to high voltage reaches greater distances when illuminated with ultraviolet light when left in the dark. The theoretical explanation was made by Albert Einstein, who in 1905 published the groundbreaking article "Heuristics for the generation and conversion of light", basing his formulation of the photoelectric work on an extension of the Max Planck quanta. Robert Andrews Millikan later spent ten years experimenting to prove Einstein's theory was wrong, to finally conclude that if the Photoelectric Effect era. The derive the equation that describes this effect in order to calculate Planck's constant and determine the work done to remove these electrons from the material. It was therefore necessary to turn on the mercury lamp and choose the lines of greater intensity. Thus, we analyze how much voltage was needed to remove electrons in different rays of light. Thus, we find the relation proposed by Einstein to explain the photoelectric effect (electron kinetic energy gives a straight line by changing the frequency of light). The slope of this is needed to calculate Planck's constant by several equations, because this is equal to the ratio of the electron charge, h (m = h / e). The product of the potential work load is (by definition of potential V = W / e). Assuming the value of the intercept will tell us the amount of work necessary to remove these electrons from the material provided. This tells us that the intercept of the equation it means is the potential to cut or braking. This cutting potential is independent of radiation intensity (I), but depends on its frequency. To derive the equation describing the photoelectric effect which is E_K=ν*h-W where the frequency of light radiation, h is Planck's constant and W is the work required to move an electron energy level. E_K is the kinetic energy of a photon emitted. We modify this equation dividing by the base load "and" and obtained a new equation: V=h/e ν-W/e

For each color there is a radiation frequency of light and a single voltage. During this experiment we measure the voltage with the team badge of each color and then create a graph of voltage vs. frequency. We relate the value of the slope of the graph with the slope of the equation "m = h / e" and cleared in order to find "h" Planck's constant experimental. Plank's constant is used to relate dimensions of mass or energy with dimensions of length or time. Because the focus of the experiment units are Planck's constant joules * seconds (Js). Using this graph and the equation above also relate the intercept value of the intercept found in the equation "b = W / e", the clear stand "W", work in units of joules (J).

2011-12-01T18:12:00.001-08:00

The Visible Spectrum… not exactly for everyone

Juan E. Miranda Sanfeliz

In our Physics II course, we have studied many topics that go from electric current, magnetic fields, circuits, light, etc. Two topics that caught my attention were the visible light and the human eye. As to why I was attracted to them was, the beauty that is our eyes for the way they produce images for us, and the light for giving us those unique colors for each of those images. In our course book, we can find information of two common defects of the human eye like myopia (nearsightedness) and hyperopia(farsightedness). Sure, these are very common amongst us and that’s why a lot people wear glasses of eye contacts, but the defect that I was curious is one not so common… colorblindness.

For better understanding of this eye defect, is best if we remember how our eyes work. The human eye sees by light stimulating the retina. The retina is consists of a complex array of nerves and receptors that are called rods and cones. The rods give us our night vision, but can’t distinguish color. On the contrary, the cones perceive color during daylight conditions. These cones contain a light sensitive pigment sensible to wavelength that goes from 400nm to 750nm, also known as the visible spectrum.

Color deficiencies as many call it, can be associated with aging but nearly all color deficiency is hereditary. The most common form of color vision, the red-green deficiencies, has been proven to be due to sex linked X- chromosomes and simple recessive hereditary traits. What’s really interesting about this condition is that a color defective male always inherits his deficiency from his mother, even if she doesn’t have color blindness; she only is the carrier of the defect. The mother would receive the color deficiency gene from her father, only if he was colorblind, or from her mother that could be a carrier o colorblind, although that last one is very improbable.

The rareness of this disease, if you call it that way, is the many types of colorblindness that they are. Many people think that if you’re colorblind you see everything around you black and white, like there was only one type of colorblindness. Fortunately for me, I knew to make this distinction because I had a History in middle school that was colorblind but his problem was with distinguishing between blue and yellow. One time, he was making a painting of a fairy with a blue dress for her niece and he ended up painting it green. Remembering that, I looked up different types of color blindness, or color vision deficiencies if you will. Base on clinical appearance, color blindness is described as total or partial. Total color blindness is much less common that partial color blindness. Under the partial color blindness, there are those who have trouble distinguishing between and green and those who have trouble distinguishing between blue and yellow. The most common defects of the last ones mentioned are protanopia (absence of red retinal receptors), deuteranopia(absence of green retinal receptors, and tritanopia (absence of blue retinal receptors). An example of these deficiencies is given in the next picture:

I know it may be sound a little awkward me seeing this, but I think is something really amazing. In our world, many things are distinguish by their color, like the grass, the clouds, the sky, to name a few, and to know that people out there haven’t seen difference. One time I was in the US for a vacation, and we stop at a red light. When I noticed, the red light had like a blinking white like in the form of a tube in front of the red bulb. I remember that I asked what was that and my cousin who lived there at the time told me that that was for the colorblind, especially the ones suffering from protanopia. After that I wondered if there was some kind of treatment for this so that people didn’t to depend on “the blinking light”.

And so, like myopia and hyperopia, you can use lenses to adjust your color sensation because you can’t really improve color vision. This concept of using lenses for correcting color vision deficiency dates back to the 1837 when a German scientist named Seeberg wrote about the possibility of correcting color vision deficiency using some sorts of lenses. But it wasn’t until the 20th century that different types of tinted lenses were developed to help colorblind improve their vision. As I mentioned before, these lenses can’t correct your color deficiency, just enhance your color perception. But like all things, it has its cons. Studies have found that color perception improves your problem area like red-green but at the expense of an increase in blue-green confusion, and that you might experience impaired judgment of distance and motion. Another con for these lenses is the cost, like $500 per lens, so not many people would be willing to pay such a high price for something that isn’t exactly a real solution for the problem, unlike a diverging lens that corrects myopia.

Reading about all this, is obvious that I learned from this “rare disease” (around 5% to 8% of the world population is colorblind) like that it is a hereditary disease, that there isn’t a cure or remedy per se for it and why people with it choose just to go on with their lives like there’s nothing wrong, maybe just confusing one color with another. But what I’m really interested is in meeting someone with total colorblindness and ask him questions like, “how your color vision deficiency has affected your performance at work?” and many others. If I had not read that part of the visible spectrum and of the human eye in our course book, I don’t think I would have read about this topic and want to look for my History teacher to maybe talk to him about something in his life other than his class. And so, I think the Physics II course achieved its goal.

References:

• Giancoli, Douglas C. Physics for Scientists & Engineers with Modern Physics. 4th ed. Vol 1. Upper saddle River, N.J. Prentice Hall, 2009. Print.

• http://colorvisiontesting.com/color2.htm

• http://www.colblindor.com/2008/03/29/improving-color-vision-with-lenses-for-the-colorblind/

• http://www.colour-blindness.com/solutions/cure/

2011-12-01T18:05:00.001-08:00

Electromagnetism – Distressed Core

Gladys N. Vega Vigo

Sound waves and electromagnetism

If we know that sound gains wavelength and looses frequency as it travels through more dense materials, then the anomalies in these waves are the means by which we can surmise the fundamental architecture of our planet. The behavior of our planet, including fauna and flora, nature itself, can be explained by the effects of electromagnetic waves. Parting from this, let’s assume the following: if a lot of people die at the same time, at the same place, let’s say, at a perimeter of two miles, and a nerve agent is not the cause of their deaths, there’s no variation in sex and age, but they all have pacemakers; then they are all susceptible to electromagnetic interference (electromagnetic impulses).

Birds navigate by sight in a short range but in a long range by magnetic fields. Little ions in their brains and vision system help them navigate using the magnetic field. Following this same line of thought, if we have a flock of birds flying violently and uncontrollably (frenzy swarm of birds) and we know it was not deliberately and it is reported, say, 53 times in different parts of the planets, then their navigation system might have been affected by electromagnetic waves.

What would be the cause of a distressed core?

Wrapped around the Earth is an invisible field of energy made of electricity and magnetisms, reason for what it’s called the electromagnetic field (EM field). It is where we get our electromagnetic North Pole and South Pole. This field protects us from magnetic radiation, but recently it’s been slowly falling apart. The Earth is composed of the crust, mantel, and the core – inner and outer core. The inner core is a big chunk of iron. The outer layer is made of hot iron and nickel at 900 degrees Fahrenheit (2,000 miles down and 1,000 miles thick) which is constantly spinning in one direction, which makes the electromagnetic field. The core is the engine that drives the electromagnetic field. And that’s where we get our problem, this engine has begun to stall; the core of the Earth has been slowly stopped spinning. The problem: it cannot be stopped. As the EM field becomes more unstable, we would begin to see isolated incidents. If it were the case that we observed this phenomenon in our present day, in a few months everything electronic would be fried. The static charges in the atmosphere will create super storms, with hundreds of lightings strikes per square mile. The Earth EM field shields us from the solar winds, which are a lethal blend of radioactive particles and microwaves. When that shield collapses, the microwave radiation will find a way to escape and literally cook our planet.

The deepest we’ve been to the core is 7 miles with a two inch drill-bit. We’re talking about millions of pounds per square inch of hot melted metal. Even if we come with a brilliant plan to fix the core we just can’t get there. On the other hand, if we somehow find a way to get to the core, the only way to fix it to its natural rotation would be with a massive explosion. We have to use wave interference in order to reestablish the rotational force of the core, because one explosion just won’t do it. Is like stones in a pond. A big stone thrown into the pond will only do a big splash. But with smaller stones, we wait until the wave is weakened and we throw another, and another and another. The ripples reinforces into geometric progression. We hold bigger than assemble apart and we’ll have hundreds megatons explosions instead of one big bang. Hence, we would see them through the core and we would haste them accurately to the inch, we detonate them in a sequence that has to be accurate to the millisecond and we would outrun the biggest nuclear shockwave in history. If there was a problem with this plan of action, it would be that the last bomb won’t be enough and it has to be at least 30% larger in order to maintain the rotational force; meaning it will need several dozen more pound of plutonium.

In these examples it can be observe how important the electromagnetism/electromagnetic field is in our everyday life and the proper functioning of our planet. Life isn’t simply a gift or a means of consuming, to some, our planet’s endless natural resources. Rather is a means of perfectly balanced cycles that have kept our planet alive for so many millions of years. Let’s hope that our future generation can realize the importance of this perfectly assembled balance before anything worse happens.

2011-12-01T17:56:00.001-08:00

Renewable Energy

Daniel Maldonado Sanchez

In our days, Puerto Rico is passing through a lot of economic problems, for example, no money for education, food or to pay the basic living things like the services of water and electricity that every day become more needed with all the technology thats coming out. We know that the resources that we use today are more expensive than ever. One of the most necessary resource for us is the electricity. As the usage of this resource becomes higher the cost also becomes higher because more oil is needed to produce it and the oil is a really expensive fuel. This resource is very important because we use it every day to study, work, eat, travel, etc. A lot of people have or have had problems with the cost of the electricity and many of them don’t have enough money to pay the high price of it. Some of the people that really don’t have the manner to find the money to support these high prices tend to steal it. However is important to know that the method of stealing it is obviously not the best and that there are many others alternatives that could be made to have this important resource without steeling it.

The renewable energy is energy that comes from natural resources that involves the use of sunlight, wind, rain and water. If we talk about the sunlight we can refer as photovoltaics. Photovoltaics is the direct conversion of light into electricity at the atomic level. The photoelectric effect that some material exhibit cause the absorb photons of light and release electrons. This occurs in the solar cells that are made of semiconductors materials such as silicon. When light strikes the cells, a portion is absorb and transfer to the semiconductor, the energy knocks electrons loose, allowing them to flow freely. When these electrons are captures, an electric current results and can be used as electricity. This solar cells can be connected in both series and parallel electrical arrangement to produce any required voltage and current combination. This use is one of the best solutions because the sun's rays give off approximately 1,000 watts of energy per square meter of the planets surface. If we collect all of that energy we could easily power our homes and offices for free.

Other renewable energy is the wind, we can use the term eolic energy. The wind energy is the energy generated by the wind and can be used directly or be transformed as electric power. It consist to use windmills for mechanical power. This method uses the kinetic energy generated by the effect of the wind. Wind energy is currently the fastest growing renewable energy and represents a large portion of the electric production.

Every time a drop of water from the rain impacts on a surface it is an opportunity missed. Each raindrop has an impact energy that is highly dependent on the size of the drop; from a small drizzle drop that has 2 microjoules on impact, to a downpour size drop that carries 1 millijoule of impact energy. A team of scientist identified that a piezoelectric material might be able to capture that energy. Piezoelectric materials generate an electrical potential when acted on by an outside physical force in this case a raindrop. They were able to capture between 1 nanojoule and 25 microjoules of energy per drop. The total power will vary incredibly depending on the conditions, but the device produces about one microwatt of power in a light drizzle. This type of device might work quite well for sensors, especially if the sensor is detecting rain. For example a weather sensor that would only send a signal of how hard it is raining, when it is in fact raining. Or how about sensors that will automatically close your house windows when a storm suddenly appears. This technology will not make up a large portion of our energy, but capturing the available energy all around us is certainly a good idea.

Another important type of renewable-energy is the water energy. Flowing water creates energy that can be captured and turned into electricity. This is called hydroelectric power or hydropower. The most common type of hydroelectric power plant uses a dam on a river to store water in a reservoir. Water released from the reservoir flows through a turbine, spinning it, which in turn activates a generator to produce electricity. But hydroelectric power doesn't necessarily require a large dam. Some hydroelectric power plants just use a small canal to channel the river water through a turbine. Another type of hydroelectric power plant, called a pumped storage plant, can even store power. The power is sent from a power grid into the electric generators. The generators then spin the turbines backward, which causes the turbines to pump water from a river or lower reservoir to an upper reservoir, where the power is stored. To use the power, the water is released from the upper reservoir back down into the river or lower reservoir. This spins the turbines forward, activating the generators to produce electricity. A small or micro-hydroelectric power system can produce enough electricity for a home, farm, or ranch.

As we can see through out all the information found the renewable energy is a method that every place of the world should be using because its very environment friendly and would contribute to a more safe and pure way of living. The use of crude oil to generate electricity is one of the main causes of Global Warming and as we said earlier renewable-energy is a very resulting way to safe the Planet. There are more ways of this type of energy but the ones that we mentioned here are the most commonly used. We have to choose if we continued to use non-renewable energy or start using renewable energy.

Reference:

Callihan, Jean. 2010. Hydropower. Taken http://www.renewableenergyworld.com/rea/tech/hydropower the day 29 of november 2011.

Company Sun & Climate. Taken from http://www.sunandclimate.com/products/6-wind-energy.html the date 27 of november 2011.

McGee, Tim. 2008. Renewable Energy. Taken from , the http://www.treehugger.com/renewable-energy/the-power-of-rain-alternative-energy.html, the date 28 of november 2011.

Types of Renewable energy. Taken from http://www.renewableenergyworld.com/rea/tech/home the date 29 of november 2011.

2011-12-01T17:51:00.001-08:00

Jumping movement: art in psychics

Eduardo A. González Falcón

Jumping or the motion of lifting a mechanical system through the air along a ballistic trajectory is a body movement that has also intrigued me. For decades I had been jumping in different sports and have always wondered why it is so versatile. Our bodies are the mechanical system as described by the meaning and we move along a trajectory just as a projectile, so there are all kinds of jumping forms which result in different distances. In volleyball and basketball some jumping movements are completely vertical, which are called vertical leap and they are created by the human body as a upward force in a same line with different height above the ground. Just as most power and mechanic systems, jumping requires great power and force in order to surpass the bodies’ gravitational force to the ground. Many people have asked me why I can jump higher than most with less difficulty, its simple the greater the speed and force the greater the power. So a skinny 150 pound body that has the same leg strength as a 200 pound body would be more likely to jump higher due to its less weight force on the ground. The other aspect which most people don’t see when jumping is the speed in which you create the force. Like in most extreme sports, the greater the velocity of a skateboard or motorbike the more distance they are going to travel and more “airtime” they are going get. Those kinetic basics are the same in the human body; the clear reason why long jump athletes start their jump approach by running a short distance with great velocity.

I visualize jumping as watching spring, the greater velocity and force done the more “pop” it is going to have and the higher and longer it will go. To find the force of a spring we calculate F=Kx where K is a constant and x is the distant vector. The same in the human body, the force to jump upward is determined by the k, which is the force constant depending on the material it is composed by (in human body visualize less mass as more powerful material due to explanation of less weight carried by object) and it also depends on the x which is the distance it can stretch. That is the reason why high jump athletes and ballerinas jump so high with so much flexibility; their muscles are normally larger, thinner and can stretch easier. It is scientifically proved that a person jumps higher when their muscles are warm and stretched because their reaction time when their bodies undergo a change in the downward/upward motion is less. Also they will more potential energy stored having greater velocity and force in that moment.

Another great questioning the basketball dunking world is the theory behind vertical leap time or as they call it “hangtime”. Why athletes like the great Michael Jordan appear to fly when they jump. All objects, in this case people have the same gravitational acceleration when they are falling to the ground which is 9.81 meters per seconds square, so appearing to have greater projectile airtime is a question of vertical displacement in the x direction with an initial jumping angle involved. A basketball superstar that has a 50 inch vertical can be less time in the air than Jordan by the only reason of the initial distance it takes off. Running then jumping from a far distance like 15 ft at a 45 degree angle will cause greater air time than elevating from a standstill position. For me the jumping movement is a great locomotive motion which I see it as an art form that involves different physics and biomechanics explanation. The ability and creative way the human uses different jumping forms is why it gives It such a versatile form of motion which it is expressed with emotions and requires great talent. Extreme sports have greatly benefited in the creation of innovative materials in their respective mechanical systems, for example skateboards which were invented no more than a century ago, have evolved greatly and the continuous research for more environmental and productive wood material will continue to go on so the human raises the bar higher and higher each time.

2011-12-01T17:47:00.001-08:00

Photoelectric effect

Marangelí Acevedo Castro

Recently in physics class we discussed the photoelectric effect developed by Albert Einstein. This photoelectric effect consists of a metal with one valence electron which is released when a photon has the enough energy to release it when is irradiated by an electromagnetic radiation, which usually is UV light. Then all valence electrons emitted by all the atoms of the metal are used as current. The photoelectric effect has a lot of uses like sensors, spectroscopy and solar cells among others.

I asked myself what if instead of using a metal with one electron in its valence shell, use a metal with two valence electrons? Or what if we can irradiate more UV light to a solar cell and not only the one emitted by the sun? Probably it would be more difficult for the electrons to be released because they will have more attraction or force between them making it more difficult to be released by the atom. If this was possible, assuming there is no attraction between the two valence electrons, a solar cell could generate, in theory, double the current a normal cell would with a metal with only one valence electron. The photons causing the release of the valence electron will need to generate more energy in order to excite the electrons and produce the current. I believe that the UV light emitted by the sun will not be sufficient to generate the amount of energy needed for the electron release. This is why I asked myself the second question mentioned before.

I read that if the light intensity is increased, this will increase the number of the photons and therefor it will be easier to release more valence electrons from the metal in the cell. After knowing this I wondered if maybe increasing the light intensity we could release the two valence electrons in the metal. In the course of physics we also learned that when a mirror is irradiated by an incident ray it is reflected with the same angle of incidence but it takes another direction unless the angle is perpendicular to the surface of the mirror. This law of reflection varies depending if the surface of the mirror is flat or with a curvature. Knowing this I thought that placing specific mirrors around the solar cell could be useful to generate more light intensity for the electron emission. Examples of metals with two electrons in the valence shield are zinc, copper, nickel and iron, among others. In my opinion I think a solar cell that could generate more current will be great for the electricity used in a house; saving energy, money and helping the environment.

2011-12-01T14:16:00.001-08:00

Why not use renewable energy?

Valerie López Carrasquillo

Energy availability of renewable energy sources is higher than traditional energy sources, yet their use is limited for now. In the following model of sustainable energy development, renewable energy sources are considered inexhaustible (sort of unlimited) while also having the advantage of clean energy (no pollutants are made during the process), defined by the following features:

-The energy-conversion systems pose a low-to-none environmental impact.

- No added potential risks in their use.

- Indirectly enrich other natural limited resources

- The proximity and transportation of energy to production sites to consumption sites may be easier in many cases.

- It can be an alternative to conventional energy sources, with the high possibility of starting a process of gradually replacing them.

Using renewable energy we could do many things; Many people like to exercise in the house and do not connect circuits to transfer that energy to household utensils such as stove, refrigerator, TV, etc..

Even better why not create a kind of fan that is loaded with wind and then use that energy to make the fan as you marched for renewable energy in the home electronic devices.

I found this on the internet that is a small example of how we could use renewable energy:

The energy must be generated, stored, processed and transported to be consumed by people, factories and other types of energy-consuming artifacts. Depending on various factors, like the distance between production and consumption centers, the economic and environmental costs are affected.

From a bigger point of view, the production and consumption of energy is, most likely, the biggest and most important instrument for development and production of practically everything, and it is directly linked to welfare and economic growth, which means that an increase in clean energy offer could allow companies to increase their demand without environmental impacts while also increasing their production facilities and growing as a company too.

Modern societies also wish to have a healthier environment, so they’re also trying to minimize any ecological impact involved in the energy production from traditional sources such as Natural Gas and Oil. It is for this important reason that the most important factor today is to encourage energy-saving methods while also introducing cleaner energy production facilities to minimize any kind of negative impact while also improving energy efficiency in consumer products, industrial process, transportation and others.

Today, modern companies have also made the jump into cleaner energies by themselves, and have even found ways to use energy with the use of cogeneration systems, as in, systems that allow the energy released to be reused, and in doing so avoids spending more on production. An example of this is the regenerating braking system found in hybrid vehicles: When the driver brakes, the driveshaft is separated from the wheels and starts to rotate an electrical alternator that, while braking the car, recharges a battery and recovers some of the energy used to push the car in the first place. Also, institutional and government campaigns have started to offer different incentives to promote the use and installation of renewable energy systems in houses and manufacturing facilities throughout the country. Industrialized countries, in order to avoid energy dependence to third parties, are encouraging diversification of energy sources and trying to achieve the most energy-auto-efficiency possible with renewable energy sources and minimizing the use of traditional not-renewable ones.

With all this, is done to minimize the environmental costs, maintaining the same levels of "being made" in part by reducing pollution, and complies with international agreements to preserve the environment.

Nevertheless, they still do not solve the major outstanding issues of resource depletion, and the total suppression of acts that cause environmental problems. Just as obvious is the solution to address an inequality different energy between countries.

2011-12-01T12:24:00.001-08:00

Static electricity shock in your home

Kevin J Bergollo Lorenzo

When the cool and dry weather is around almost everything you touch made you feel an electric shock. This effects are very common for those how live in near to the north were the temperature are low then 50oC. Static electricity is refers to the buildup of electric charge on the surface of object, when electrons move from one surface to another through contact. All material is made of electrical charges in the material atoms. In the universe there are equal amount of positive charge and negative charge, these particles always try to stay in balance by Coulomb’s law F=(Q_1 Q_2)/(4πr^2 ε_0 ), forcing the same amount of particles to move from one side to another. When one object is in contact with another object some of the charges redistribute from one material to the other. The electric field is created when charges are moved by a force, E=F/q. If one of the charge materials touches a conductor, like a metal, the charge will neutralize itself, living positive charge on one object and the same amount in negative charge on the other, Gauss' law states that "the total electric flux through a closed surface is proportional to the total electric charge enclosed within the surface", so the potential difference is ΔV=∮_s^ ▒〖E*dA〗.

So, why you feel a static shock when you made contact with some metal, like the doorknob? Well, most of the people have insulator in their homes and in them self, like the rubber soles of a shoes or a wool carpet in the floor. When you walk on that wool carpet, your body builds up a charge it can’t get rid of because the insulator of the shoes. The air when it dry work like insulator, that why static electricity are more common in dry winter months, that so when you touch that metal doorknob feels el shock in it. Walking around is not the only way to generate electric static, some time sitting in a chair and creating contact between your clothes and the chair can generate a lot of static on your clothes. While the body stays on contact with the chair your body voltage stays low, if the body is separated from the chair, take the charge with it, rising up your body voltage. Not all people feel the same way with the same amount of charge in the body. Some people are more sensitive to shocks than others, for some people the range for feeling the electricity is 2.00V – 4.00V. In other cases some bodies store more static electricity, all depends on the size of the bodies, the size on the feet and the thickness of the shoe soles. Some of the remedies to lower the electrostatic in your home are raising the air humidity to a 40-50% with a humidifier. Also is prefer to use leather soles shoes, there are some antistatic sprays available to treat chair and other furniture. The spark can provoke fire or even worst can be extremely dangerous in combination of a combustion gas.

2011-12-01T11:38:00.001-08:00

Measuring the speed of light with a microwave oven

Moisés Montalvo Lafontaine

To measure the speed of an object we just need to know the time it takes the object to travel certain distance and use Newton’s law of motion. It sound simple and it is. But how the speed of light is measure using this technique? Well is hard to do it with accuracy because the speed of light is so high that the time it takes to travel some measurable distance is extremely small. So I wonder how it was measure. But most important to me is how I can measure it myself. Well it turns out to be easy to do and we all have the equipment to do it: the microwave oven.

First let’s explain the early attempts to measure the speed of light. Galileo tried to measure it using a lamp at a great distance but he concluded that the speed must be extremely high to be measure. To perform better measurements it was required a laboratory environment. Albert A. Michelson used the rotating mirror apparatus shown below. This had higher precision than previous ones and it gave Michelson a good value of the speed of light in the air. As we can see in the diagram the apparatus measurement was purely mechanical. But with this apparatus Albert A. Michelson performed measurements good to nearly one part in ten thousand.

(http://www.setterfield.org/assets/images/cx4_clip_image001.gif)

With the advances in technology, better measures were made at the National Institute of Standards and Technology (NIST). This new techniques reduced 100-times the uncertainty for the value of the speed of light. Of course is not a technique as simple and mechanical as the early ones because it’s based in the atomic/molecular measurements using a helium-neon laser. The speed of light is defined to be 299,792,458 m/s (or 3 X 10^8 m/s when high precision is not require). Because this value is constant the meter was redefine in terms of the speed of light using the relation c=νλ.

Like a mention before, we can calculate the speed of light using a microwave oven. We can do it theoretically or experimentally. The frequency v in a microwave oven is usually 2.45 gigahertz. At this frequency, water molecules resonates releasing heat. The distance from peak to peak of microwaves (wavelength λ) is almost 12.2 centimeters. So using the formula c=νλ we obtain c=(2.45X10^9 Hertz)*(0.122 m) = 2.989X10^8 m/s. This result was obtained using the theoretical values of the microwave oven operating frequency and wavelength. How can we determine this experimentally? First, and very important, we have to take out the rotating plate. What this plate does is rotate the food so it can be heat evenly because the microwaves are emitted “linearly”. Use cheese and microwave it for a couple of seconds. The cheese is going to melt but not uniformly. Is going to melt only in the spot were the microwave hits it. Measure the distance (in meters) between the centers of the spots. That distance is half the wavelength of the light so it has to be doubled in order to obtain λ = 0.122 m. Multiply that by the frequency of the microwave v = 2.45X10^9 Hertz and the velocity of light (in the air) is obtain.

http://www.scientificamerican.com/article.cfm?id=microwaves-and-the-speed

http://www.scientificamerican.com/article.cfm?id=how-the-microwave-works

http://www.scientificamerican.com/slideshow.cfm?id=how-the-microwave-works

2011-12-01T11:31:00.001-08:00

Interference and diffraction throughout physics

Luis A. Muñoz Torres

The sources are those that emit coherent light waves of the same wavelength or frequency which are always in phase with each other or have a constant phase difference. The two coherent sources can produce the phenomenon of interference. The colors that we see when sunlight falls on a soap bubble, a little oil or wet pavement, or a red hummingbird are caused by interference of light waves reflected from the front to the back of the surfaces of thin transparent films. This is because two beams of waves arriving at the same level if they add their effects in phase or counteract its effects if they date. Their combined effect is obtained by adding algebraically the displacements at the point to the sources individually. This is known as the principle of superposition.

Young's experiment seeking behavior or the nature of light. With a dual-slot grille experimentation was carried out very similar to this interference experiment which sought to show whether light consists of particles or waves passing through the dual grid. Was observed pattern formed on the white screen. If light consisted of particles have been observed two white stripes on the screen however, there was a distinct pattern on the screen which had a larger line in the center and smaller stripes on each side. This is due to the phenomenon of wave diffraction and interference the light passing through the diffraction gratings and then suffer the light of the grids interferes with light passing through the other grid and that is why it forms a most intense line in the center of the screen. There is constructive interference and destructive interference that is why we see dark spaces between each line and in the center look brighter light because there we have constructive interference.

Data obtained in the experiment shows the distance between the center of the peak and each peak. The light intensity as a function of linear position. The peaks represent locations where the bands are intense in the white screen (constructive interference) and represent the minimum destructive interference. As the number n peak distance increases and the peaks are decreasing intensity. The formula that relates the distance (Dx), the wavelength (λ), the separation between the slits (d) and the distance between the device and the sensor grid of light (L) is: dΔx / L = nλ.

We show the behavior of interference of light waves. It can be seen clearly as peaks and troughs are not defined very well. This is why the measure was taken away from the low near each side of the central peak. Constructive and destructive interference cannot be seen as clearly as when using the dual grid.

By observing the behavior of light diffracted as it passes through the interference grids shows that the laser passes through the grid divided into upper and lower those in the light sensor as points. This is because the light as it passes through the grating is diffracted simple. In the experiment of additional double grating diffraction, we observe the interference effect in which the peaks of the wave are altered as two waves intersect and cause interference.

2011-12-01T11:25:00.001-08:00

The Physical Formulation behind the Refrigerator

Omar R Diaz Rodriguez

After looking at the device closely, one is able to observe the physical formulation behind it. A refrigerator is a common household appliance that consists of a thermally insulated compartment and a heat pump that transfers heat from the inside of the fridge to its external environment so that the inside of the fridge is cooled to a temperature below the ambient temperature of the room. The purpose of the refrigerator is to keep whatever is put inside it cold. This device use an ingenious system to move hit from inside out by transferring heat. To create cold a fridge absorbs hot air and dumps it outside, furthermore for that it relays in a system of coils.

With this object, an aluminum coil inside the refrigeration chamber forms the evaporator. The cooper coil that snakes around the outside of the chamber, under the fridges metallic shell, is the condenser. Nevertheless, both sets of coils are responsible for the heat transfer. They move the heat from inside the fridge to the outside air, leaving cold air behind in the chamber.

For this purpose, once the heat is absorbed by the coils, the cold air left behind needs to be preserved; hence insulation surrounds the fridge chamber. To this end, every space and every crack is field from the air tight sealed of rubber stripping around the door to the polystyrene and insulating foam in its walls. As a result, the insulation keeps the cold air in, and the heat out. Furthermore, that includes the heat that is expelled by the fridge itself.

On the other hand, the evaporator coil is nestled between the fridge and the freezer. The coils are filled with refrigerant, a special mixture of chemicals called hydro floral carbons, which have the unique property of easily absorbing and releasing heat. Additionally, in order to achieve refrigeration the evaporator coil is strategically placed, since hot air rises it comes into contact with the evaporator coil that sucks up the heat leaving cold air behind. The condenser coil wraps around the extremities of the fridge getting rid of all the heat and expelling it into the cooler air around the fridge.

With this object, to fully understand the physical formulation behind the product it had to be dissected. With the use of a screw driver the door was extracted, in addition the shelves and the outside layer of the refrigerator were taken out in order to analyzed the inside of the device. It is important to mention that to carry out this procedure, one must use safety equipment.

In addition, is important to specify that the refrigerator that is being analyzed is a cabinet-depth refrigerator. With this purpose, the consumer has some pros and some cons when buying this type of refrigerator. Some advantages of buying this model are that this one sticks out only a bit farther than built-in models and that usually accept extra-panels for to achieve a custom look. On the other hand, some disadvantages are that this model has less space than the deeper freestanding models and cost more.

2011-12-01T11:20:00.001-08:00

Gravitation and dark energy

Francisco J vergara

If we look back at our principles of gravity it will be clear that objects tend to attract each other’s. If we apply that to the universe, knowing that the universe is full of matter the attractive force between matters will pull all matter together. If we know this we could say that in theory the expansion of the universe had to slow, to a point that it would stop and recollapse. But certainly that’s not happening. In fact recent studies prove that the universe has been accelerating. But what is causing the universe to accelerate it expansion? Maybe there is something wrong with the Einstein theory of gravity? We really don’t know but Theorists gives the solution a name ‘Dark energy’

But what is Dark energy after I make my research in this topic I realize that there is more unknown than know, the only know is that it’s affecting the universe expansion. In fact we could say that practically nothing is known and that’s what makes this topic so interesting. There are some theories about dark energy first we have Einstein theory that says that empty space can possess its own energy and as more universe come into existence there would be more energy and so on this continuous expansion and acquirement of energy will cause the universe to accelerate faster and faster but this is only a theory.

Another theory that I found pretty interesting is that dark energy could be a new form of energy fluid or field. But this is no normal energy at least not as we know it, this kind of new energy will have an effect on the universe expansion that is totally the opposite of that of normal matter and energy. If it it’s totally opposite that could perfectly explains why universe is accelerating. Matter and normal energy will cause the universe expansion to slow down but this kind of unknown energy will cause it to accelerate. If we take a look at the numbers we could see that there’s only 5% of normal matter in the universe 75% of dark energy and 25% of dark matter. Then it is obvious that there is more energy making the universe to expand that the energy that is making it to slow down. Theorist call this energy "quintessence," , but all this is a theory we don’t know if it really exist and if that was the case we don’t know why it’s there and so the mystery continues.

Maybe the only theory is that Einstein was wrong but this would affect the expansion of the universe as we know it. In fact this would lead to decide a solution to this dark energy problem. But what it would be? Another gravity theory? If another gravity theory would be the solution. What it would be? There are lot of theories but we can’t prove them at least not we the knowledge we have in our days. I am anxious that someday preferably not too far scientist could be able to solve this whole mystery once and for all, and came with a new theory of gravity if that is the case.

Here is a link to an article that I found interesting about a new method to see gravitation and dark energy: http://hubblesite.org/newscenter/archive/releases/2010/26/full/

2011-12-01T11:15:00.001-08:00

Topic of Magnetism

Kermelr Ruperto Justiniano

When we think about physic, we think about strength, we think the action of moving an object, dropping things, etc. In my studies of physics without doubt one of the issues but to draw attention to me as a kid I was curious is the subject of magnetism. When a child sees as certain materials are attracted to each other and one asks, "How that occur?" or "Why that occur?". And here where the physics helped me to understand part of why and how this phenomenon occurs that is so important in life on earth as in many of the artifacts that we use.

To give a simple definition of what we could say that magnetism is a fundamental force in our nature, which is one of the forces is used in many of the components used and an used such as the compass. Magnetism occurs when when certain charged particles set in motion. We see mostly, but do not know when certain materials attract or repel. There will be seen when they are two magnets, if you put glue on one side or else try to separade and try to unite them more than you do not. This is where true strength of attraction and repulsion. These issues go beyond simply paste or separate things. The magnetism able to help scientists understand atomic structures.

The area includes many magnetism such as electromagnetism that surrounds what is electricity. These areas were studied years ago simultaneously and noticed that there was a relationship between them. Behaviors were observed that when a magnet as it approached a induce cable is produced or an electric current in the cable (discovered by Michael Faraday). It was also noted that there were internal magnetic fields in materials such as iron (Ernst Weiss), among other things. With all this research is an able to do many simulations and research. Going back fully to the magnetism is a very interesting are the magnetic fields, which also involve electricity in some cases.Una bar magnet or current-carrying wire can influence other magnetic materials without touching them physically because magnetic objects produce a 'field magnetic'. Magnetic fields are usually represented by 'magnetic field lines' or 'lines of force'. At any point, the direction of the magnetic field is equal to the direction of the lines of force. After saying this, I explain the workings of one of the things that after seeing and learning in my class that I decided to take on the task of seeing how the compass works is that an object that looks simple but it is, we can see that is physically behind his invention.

The compass lets us know according to the place where we stand, to where is north, but, "How this happen?". The compass needle is a needle that magnetism and rotates about an axis. This indicates the direction north and south magnetic pole. The movement of the needle and the sense tell us that we must turn occurs internally and the earth has a magnetic field, where the South Pole of the field is in the North pole of the earth and the North Pole is in the field the South Pole of the earth. The needle and said that this magnet with the North Pole, opposite the South Pole of the earth's magnetic field. As explained earlier the opposite poles attract, for that reason the North pole of the compass is attracted the south pole of the earth's magnetic field which in turn is at the geographic North Pole. This is why we always tell the compass to where the North. Although I have to first admit that physics is not 100% mine, I must say it helps explain many of the situations that you are not even know why or how they occur.

2011-12-01T11:10:00.001-08:00

Is the Relativity’s theory of Einstein wrong?

Mileyska Rodriguez Roman

As students we have learned that all this time there does not exist any particle faster than the speed of light, because that was proved experimentally by Albert Einstein. Our studies in physics normally are based on Einstein’s theories; also our world is described and explained by him. The question is what happens if some scientists discover that the theories of Einstein can be wrong? That really there exists a particle faster than light. That's something that according to Einstein's 1905 special theory of relativity, the famous E = m equation, just doesn't happen. Let’s examine the experiment that some scientists are doing to prove that there exists a particle faster than light and what will happens if it is true.

Who was Einstein? Albert Einstein was a very recognized German physicist who developed the theory of general relativity, affecting a revolution in physics. He received the 1921 Nobel Prize in Physics for his services to theoretical physics, and especially for his discovery of the law of the photoelectric effect. The latter was pivotal in establishing quantum theory within physics. He realized the inadequacies of Newtonian mechanics and his special theory of relativity stemmed from an attempt to reconcile the laws of mechanics with the laws of the electromagnetic field. Those theories mentioned above are only a little part of all the things that Einstein discover and proved experimentally, he was a genius and for this achievement, Einstein is often regarded as the father of modern physics and one of the most prolific intellects in human history.

What is the theory of the relativity and how it works? The theory of relativity said that the speed of light in a vacuum is constant and an absolute physical boundary for motion. It states that objects will move slower and shorten in length from the point of view of an observer on Earth. This theory is divided in two parts. The first is the Special Theory of Relativity which states that motion and rest are relative. The second is the General Theory of Relativity which applies to particles that accelerate due to gravitation and states that objects continue to move in a straight line in space-time, but we observe the motion as acceleration because of the curved nature of space-time. This theory was confirmed when occur a solar eclipse in 1919 where the light of the stars was deflected by the sun as the light passes through the earth.

We have known all of the past centuries of physics, now it’s time to know what happened to disregard what have been proved in the past by Einstein. A few scientists from Italy made an experiment named OPERA with neutrinos where these particles appear to be faster than the light. Neutrinos are similar to electrons instead they do not have electric charge, they are neutral. Because of that they are not affected by electromagnetic forces. These particles are able to pass through great distances in matter without being affected by it. OPERA is a neutrino detector built in a cavern under the Gran Sasso mount in central Italy. It is called long baseline experiment, which receives neutrinos of the muon type produced by the interactions of 400 GeV protons with the CNGS neutrino beam facility at the CERN laboratory, 454 miles away. The study is based upon the transformation of the muon variety of neutrinos into the tau variety where they are trying to explain the result that the neutrinos appeared to travel faster than the speed of light.

No matter what the CERN prove the velocity of light is constant and is going to be 300,000 km/s every time because this is a natural characteristic. This is not the part of the theory affected because if it were then the experiment would find photons faster than light when that is not the case. Then, what is the case? What happened? The problem is that the speed of light supposed to be a limiting velocity, if the CERN disregard this then it could affect some mathematical computes. For example, a theory predicts that objects that move with a velocity v close to the speed of light c are contracted and their times become longer; the point is that the mathematics of the theory breaks down for values of v = c for instances where the movement of the object is equal to the speed of light. Moreover, it will occur a critical situation because if neutrinos are faster then theories of Einstein will be falsified.

I think that there are many different ways to analyze these particles. If we examine the trajectory of each particle, for example, the neutrino travels in a horizontal path and the light travels in a curvilinear path, then the neutrinos will be faster. It could be an error of Einstein or the CERN, so they have to keep analyzing all the possible variables experimentally and determine what makes more sense. If Einstein is wrong then it’s the beginning of a new revolutionary of physics.

2011-12-01T10:56:00.001-08:00

Plutonium-238 and RTG’s use on “Curiosity” and other NASA robots

Raquel I. Quiñones Acosta

Physics laws, ideas and discoveries started out as simple curiosity of a person or group of persons. A perfect match for my curiosity launched to Mars these past days (November 26, 2011) from Kennedy Space Center, FL. “Curiosity” as the Mars new rover was named, has been set to arrive Mars soil on August 6, 2012. The huge robot weighs five times what the rovers Spirit and Opportunity did. Its mission is to find out whether Mars has or had some sort of life. Studies made, arise the thought of Mars soils possibilities to have microbial life. Something as simple as a salt mixture can create a habitable place for microbial life to take part. This because the levels of deliquescence inside the salt mixtures increase, becoming a source for life on Mars soils as it has been proven to happen on the Atacama Desert and other Mars alike soils on Earth by NASA’s scientists Christopher P. McKay and Alfonso Dávila among others. This mission as many other NASA missions has the capability of arising new important discoveries for our generation and the generations to come.

Curiosity will have the capability to be a field geologist and a laboratory simultaneously. Another interesting fact would be the energy source for the rover. As the other NASA rovers, Curiosity will have solar panels to provide energy and a plutonium battery to maintain all parts of the robot working properly. NASA has employed plutonium material batteries to keep the robots warm and collect data for a longer period of time. Plutonium material batteries can make the robots work for years; and even after 10 years the battery produces 92% of its initial energy, making them a powerful tool on our engineering world. According to Michael Banks from Physics World; Curiosity will have enough energy to fire a laser with a 1067 nm wavelength and a power of 10 MW to deposit 15 mJ of energy onto a millimeter spot of rock to break it down. Then the robot will have the capacity of analyzing the data to determine chemical composition.

Focusing on the batteries as the source of energy, basic physics terms explain that a normal battery transforms chemical energy into electric energy. Plutonium material batteries are nuclear batteries that use thermal energy to produce electrical energy. Plutonium-238 has been used for decades in radioisotope thermal generators (RTG’s) and the heat energy or electrical energy produced by them maintains the products working for longer considerable periods of time. Plutonium-238 produces 1 kilowatt of energy per 2 kilograms of mass. In the case of the rover Curiosity this type of battery is indispensable for its proper functioning, but yet very expensive. Still alpha particles responsible for the energy on RTG’s are one of the highest energy sources employed by humanity on the military, space and heart pacemakers, because of the mentioned ability of longer-lasting useful life. Alpha particles are responsible for the high energy nuclear reactions necessary for the robots, landers, rovers and other devices prepared for space studies to last long enough for discoveries farther away from the sun than our planet Earth. Probably physicist Ernest Rutherford never imagined that his studies on alpha particles would have such a large and amazing impact on our actual studies for the search of life on other planets.

2011-12-01T10:52:00.000-08:00

DIGITAL CONTACT LENSES: THE EYES OF THE FUTURE

Yrret Maldonado Ortiz

Envision the idea of being constantly updated with the latest information. At the present time the possibilities are remarkable. An international team of researchers has developed the first working prototype for such a device. In a study published in the Journal of Micromechanics and Microengineering, the researchers from the University of Washington, Seattle, and Aalto University in Finland describe the construction of a computerized single pixel contact lens and demonstrated its safety by testing it on live eyes that showed no adverse side effects.

The prototype contact lens has the capacity of streaming real-time information across the field of vision; potentially providing the wearer with information updates. This device is an example of the integration of devices into miniaturization unconventional substrates. The lens display consists of an antenna to harvest power sent out by an external source, as well as an integrated circuit to store this energy and transfer it to a transparent sapphire chip containing a single blue LED.

One of the mayor challenges the researchers had to face in the design process of generating the contact lens was due to the required small size of the nature of the contact lens and that due to the fact that the human eye has a minimum focal distance which is at least several centimetre away, therefore objects on a contact lens cannot be resolved, making the information in the lens itself look blurry and out of focus. In order to resolve this problem researcher employed a set of a class of micro-lens known as micro-Fresnel lenses, which focus light by refraction in a set of concentric curved surfaces. Their design allows the construction of lenses of large aperture and short focal length without the mass and volume of material that would be required by a lens of conventional design. Compared to conventional bulky lenses, the Fresnel lens is much thinner, larger, flatter and have shorter focal lenghts, allowing it to focus the projected image onto the retina. Therefore the use of this Fresnel lenses in the design of the contact lens is ideal, because it does not only help solve the problem of the image projection on the retina, making the lens more biocompatible but it also fits the required measurements of volume needed in order to use it in the design of the contact lens.

In order for the lens to acquire the necessary energy for the system to operate without a wired connection, researchers had to developed an CMOS integrated circuit because it meet the terms of the limitation of the design of the lens. Since the strict low power consumption and small footprint requirements in the design of the contact lens prohibited the use of commercially available integrated circuits. Therefore the researchers had to design a custom IC to perform control and radio functions. In order to be able to incorporate the wireless electronics onto a contact lens. This chip design by the researcher has the ability as the lead researcher Babak Parviz from the university of Washington establish to perform the following tasks: “the conversion of RF power received by the on-lens antenna to a dc-supply voltage, on-chip energy storage sufficient to excite the micro-LED, and generation of an on-chip clock source to duty cycle an LED driver switch.”

Custom designed and fabricated power harvesting and LED driver circuit. (a) Schematic of the CMOS IC architecture and connectivity. (b) Photograph of assembled chip with rectiﬁer and storage capacitor outlined in white, viewed through the polymer substrate. Scale bar is 250μm.

The power management circuitry consists of a ring oscillator, a pulse generator and a passive level shifter. As established by the researchers, “the ring oscillator is powered from the second stage of an eight-stage cascaded rectiﬁer. Each inverter in the three-stage oscillator uses stacked high-threshold devices for low leakage and low-power operation.” As a result, (as the research should) the power consumption of the ring oscillator is less than 500 nW at 1.0 MHz.

The device could overlay computer-generated visual information making it easy to access information instantly from platforms such as mobile phones. The researchers claim that their device will have a wide range of uses; that goes from leisure in its use for gaming devices and navigation system as it can be employed for educational, health application, such as a biosensor and even as an aid to the hearing impaired. Signiﬁcant improvements are necessary to produce fully functional, remotely powered, high-resolution displays. However the research, data, results and design that wave been obtained by this group of researcher have establish a create stepping stone in the fundamental change of how people access and interact with visual information and how they see the world.

Reference:

A single-pixel wireless contact lens display

A R Lingley1, M Ali2, Y Liao1, R Mirjalili1, M Klonner2, M Sopanen2, S Suihkonen2, T Shen3, B P Otis1, H Lipsanen2 and B A Parviz1

Journal of Micromechanics and Microengineering, Vol.21, Num.12, 125014, 2011

1317_21_12_125014.pdf>

"Digital Contact Lenses Come into Focus." Physicsworld.com. Web. 30 Nov. 2011. .

Future Contact Lenses Can Put Pixels on Our Eyeballs

By Ross A. Lincoln - 12:00 AM - November 26, 2011

http://www.tomsguide.com/us/1-Pixel-Contact-Lens-HUD-implant,news- 13298.html

"Fresnel Lenses." Michigan. Web. 01 Dec. 2011. .

^ "Fresnel lens." Encyclopædia Britannica. 2005. Encyclopædia Britannica Online. 11 November 2005.

2011-11-30T19:05:00.001-08:00

EUV

Mauricio M. Ortega

When it comes to Physics, there is definitely a wide array of topics that come to mind. We’ve learned so much this semester and there’s still so much more to learn. I, personally, am interested a lot in radiation; so I set myself to find out how it’s being used in today’s world to better our technology. The answer was lithography. Optical exposure technology has already reached its limit. Extreme Ultraviolet lithography will hopefully take over, becoming the leading contender, establishing the new generation of lithography. One critical problem is to develop a source-emitting radiation with high power and life time at a short wavelength such as 13 to 14 nanometers. The production of EUV radiation includes two possible processes, the laser-produced plasma and the discharge-produced plasma. Oxygen, Lithium, Tin and Xenon were considered for the development of the source, but due to Xenon’s low conversion efficiency we might be able to produce a higher quantity of photons. Laser-Produced Plasma is focused on a Xenon beam which also presents some problems, for example, it is required an exact pulse duration with an exact power output. Additionally the difficulty to control this process is very high. Due to these LPP issues, interest in DPP has increased. But the biggest advantage of DPP it has to be its simplicity to control and its cost-effectiveness. With Z-pinch discharge the magnetic field compresses the plasma to a capillary of 3mm and 5mm diameter, for later production of EUV radiation. Xenon will emit EUV, which will flow through the discharge tubes of 3mm and 5mm.

The Z-pinch plasma is characterized by measurement of its temporal intensity. The discharge current is detected by a pick-up coil. The energy for this process will be provided by a magnetic pulse compressor exceeding a 90% of energy efficiency. The EUV energy is measured with a monitor that consists of a filters and diode tools. A pinhole camera, filter, a multichannel plate-image intensifier and a digital camera will be used to record time-resolved images of the discharge plasma around the EUV wavelength. The Z-pinch design and circuit pulsed-power excitation parameters will be optimized to achieve the required characteristics for the source-emitting radiation needed in the first place.

In today’s market, between laser-produced plasmas (LPP) and gas discharge-produced plasma (DPP), DPP is currently the most powerful EUV source. Despite its superiority to LPP, DPP still faces problems such as the thermal load on the components. This particular problem causes the degradation of the lifetime of the components, such as the electrodes, the insulator wall, and the light-handling mirrors. This problem was solved by shortening the discharge current pulses, reducing thermal problems and improving conversion efficiency from the discharge energy to the in-band EUV emission power (CE).

As for the monitoring of the DPP, the temporal development of the relative EUV emission intensity is monitored by a fast PIN photodiode (Hamamatsu, 3883, 300MHz) covered with a 150-nm-thick Zr filter Luxel). The intensity of the EUV radiation depends on the Xenon flow rate. These two are directly proportional. However, at a too large flow rate, EUV intensity tends to decrease and maximum emission is delayed. Moreover, the vacuum level in the discharge chamber changes with the xenon gas flow rate which absorbs, partially, the EUV radiation. Now, EUV emissions not only strongly depends upon discharge current (amplitude, duration), but also on the filling-gas pressure or xenon gas flow rate delivered to the discharge chamber. The emission spectrum of the radiation was measured with a reflection grating spectrograph including a flat-field grating and a charge-coupled device detector. For the amplitude of the current and the Xenon flow rate is influenced by the temperature. We find proof for this in several studies on the EUV spectra of DPPs reported that the 4d-4f transition of Xe¬11+ becomes stronger for higher electron temperature.

Lastly, and in general, the EUV emission energy from these pinched plasmas tends to be proportional to the square of the peak current amplitude. On the other hand, the increase in electrical energy input to the discharge causes the ablation of electrodes and insulator wall, which results in the generation of large amount of debris and the impurity contamination in the target plasmas. In order to increase EUV power without increasing energy input, a key issue is to improve the conversion efficiency for the discharge energy to the in-band CE. One is to use tin or lithium plasmas. The other is to optimize the plasma temperature and density for the 13.5 nm emission. The formation process of the high-energy-density plasmas in a DPP scheme is flexible compared with an LPP scheme and is dependent on the current waveform, electrode geometry, and the target gas, gas pressure, and gas initial ionization state.

So what do we make out of all of this? EUV is evidently the way of the future as far as lithography, for the time being. The ability to transfer a geometric pattern from a photomask to a light-sensitive chemical "photoresist", or simply "resist," on the substrate is a priceless for circuits. However, the smaller we can make these patterns, the better, and the more efficient. That’s what EUV is bringing to the table, the ability to do this at an even smaller scale than previous technologies such as photolithography, and allow us to create smaller electronics. Paving the way for nanotechnology.

Works Cited

Zhang, C. H., P. Lv, Y. P. Zhao, Q. Wang, S. Katsuki, T. Namihira, H. Horta, H. Imamura, Y. Kondo, and H. Akiyama. "Xenon Discharge-Produced Plasma Radiation Source for EUV Lithography." IEEE Transactions on Industry Applications 46.4 (2010): 1661-666. Print.

2011-11-30T18:42:00.001-08:00

Electric Forces in Deoxyribonucleic Acid (DNA)

Iliane Miranda Fonseca

The concept of electric force studied in Physics II can be applied to other science fields such as Biology, specifically Molecular Biology. Our body is compound of billions of cells and each one has many molecules that interact with each other to perform a specific function. These interactions occur in water, because this is the main component inside the cell. Water is a polar molecule which has a dipole moment and can interact with other water molecules forming hydrogen bonds, or also can be able to interact with other molecules such as DNA, RNA, and proteins. The electrons in water spend more time around the oxygen atom than around the two hydrogen atoms making the oxygen more negatively charge.

In the case of the proteins, biochemical compounds consisting of one or more polypeptides, there are six forces or bonds that stabilized its tridimensional structure. These are the following: ionic bond, covalent bond, Van de Walls forces, hydrogen bond, electrostatic forces, and intermolecular forces. One example is the ionic bond which is form when a positive atom (cation) and a negative atom (anion) can hold together under electrostatic attraction because of the opposite charges. As we learned in physics II, “unlike charges attract; like charges repel”. Another example is the intermolecular forces due to molecules with dipolar moment that are attracted with others dipolar molecules electrostatically.

The DNA contains the hereditary material or genetic information that is passed from one generation to other. This molecule is made up of nucleotides, and each nucleotide is composed of one nitrogenous base, a deoxyribose, and a phosphate group. Adenine (A), guanine (G), cytosine (C), and thymine (T) are the four nitrogenous bases. The DNA consists of 2 strands that are wrapped forming a double helix. The two strands are attracted because of the electrostatic forces between the nitrogenous bases which are positively or negatively charged forming a hydrogen bond. This electrostatic attraction is very important to transmit the genetic information with precision to the other generation. As we can see in the following picture, adenine is always attracted to thymine and guanines to cytosine because this is the most stable form.

The concept of the Coulomb force acting at a distance can be applied to the DNA using gel electrophoresis. This is a technique in where the DNA fragments or other molecules can be separate based on the mobility of ions in an electric field. Since the DNA is negatively charged when dissolved in water, the electrophoresis will separate the DNA by size. This is because small molecules migrate more easily through the gel matrix while bigger molecules experience a larger resistance. The DNA is placed in a side of the gel and by applying an external electric field it will move to the positive side. The picture at the left is how this technique works and the one at the right is a result of the DNA gel electrophoresis.

As we can see, Physics is everywhere including our own body. The laws of Physics can apply to almost all other science and engineering fields and for this reason is very important to understand and learn more about Physics.

References:

1. Deoxyribo Nucleic Acid

http://mrsec.wisc.edu/Edetc/background/DNA/DNAintro.htm (Acceded November 23, 2011)

2. Electric Fields – Coulomb Force at a Distance. http://www.physics.udel.edu/~bcwalker/phys208/lab2.pdf (Acceded November 23, 2011)

3. Giancoli, Douglas C. Physics for Scientists and Engineers with Modern Physics. 4th ed. Vol. II. Upper Saddle River, N.J: Prentice Hall, 2009. Print.

2011-11-30T18:37:00.001-08:00

Are Neutrinos Faster than Light?  

Kevin J Soto Villanueva

Several days ago, there was a commotion in the Physics world. Scientists of the CERN discovered that a previously known particle called neutrino travels faster than light. But, is this phenomenon possible? According to the special relativity theory that we learned in Physics, which in part states that light is always propagated in empty space with a definite velocity c (one of the fundamental constant of nature), which is independent of the state of motion of the emitting body, it cannot be.

Neutrinos are particles that emerge in nuclear reactions, radioactive decay, nuclear bomb explosions and death of stars exploding in supernova. They are uncharged particle, fermionic type with half a spin. These particles have mass, but very small, and it is very difficult to measure it, which implies that they are not affected by electromagnetic forces, and gravity has little influence on them.

We know that to accelerate a body, you have to apply an energy, bodies with greater mass, the greater the energy that should be applied. As we approach the speed of light (c), the mass of the moving body increases more rapidly, so that to continue accelerating, and as we get closer to "c", the mass of the object gets closer to infinite magnitudes. This would be absurd because it is not possible to apply such energy, as well that is impossible the existence of a body of infinite mass. This is the reason nothing can travel faster than light. In advance, we can deduce that to accelerate a neutrino at speeds approaching that of light is much easier than to accelerate a proton, since it has less than a billionth of the mass of it. However, despite this apparent ease to accelerate it, the theory of relativity demonstrates that even the very small mass of neutrino, in order to accelerate it, will increase the more it approaches "c". Then by the theory, there is no place for the neutrino; if it wants to travel at the speed of light it'll require infinite energy.

What this phenomenon could change is variable. From the size and age of the Universe to the distance of the stars and galaxies. All of them would be miscalculated and would need to be done again. Also one such possibility is to look again at the 'mass' of photons, because they may have it and are beyond the limits of detection, thus traveling at the speed of light does not alter the principles of relativity. Either Einsteinium physics are right and nothing travels faster than the speed light or it is wrong, maybe incomplete and scientists will need to rebuild the theory of relativity from the start up. Neutrinos have been a difficult particle to study, unreactive, illusive and even ghostly. They can pass through the heart of a star and not interact with a single particle of matter. It's more likely that this discovery may finally answer why neutrinos are so hard to detect or interact with. Maybe they are able to burrow in and out to different dimensions. It would allow them to travel faster than light not by exceeding light speed itself, but by taking what we can call “shortcuts”. How they do that though will be an interesting process of discovery.

2011-11-30T18:11:00.001-08:00

How do Cameras relate to our Physics Class

Adriana C. Santos-Rodríguez

Have you ever wondered how a camera works? It’s pretty amazing to see what it can do, but how does it do it? This very popular device used in the 21st century, were even cell phones have tiny ones. The basic principles on how a camera works are learned in our very own Physics class. A digital camera takes light and focuses it via the lens onto a sensor made out of silicon. It produces the photos by converting light particles into electricity. The basic technology that makes all of this possible is not very complicated. A camera is basically made of three basic elements: an optical element, a chemical element and a mechanical element. As you can see the only trick to making a camera is combining these elements to create this wonderful device. In this article, we will restrict our information on the optical element, because it is of more relevance to the class. The optical component of the camera is the lens. Like we studied in class, a lens is an optical device with perfect or approximate axial symmetry which transmits and refracts light, converging or diverging the beam. At its simplest, a lens is just a curved piece of glass or plastic. Its job is to take the beams of light bouncing off of an object and redirect them so they come together to form a real image, an image that looks like you can see on the lens. The lens slows down the light, as we know light travels at different speeds depending on the medium, in the air it travels faster than when it reaches the glass of the lense, therefore helping us capture the image. The light waves enter the lens at an angle, and slowly the wave will reduce it speed. This angle causes the light to bend in one direction, and it causes it to bend again when exiting the lens. This causes that parts of the light wave enter the air and speed up before other parts. In a double convex lens, the light will bend when it exits as well as when it enters. The convex lens takes the light rays and redirects them to the light source, creating a real image where the light rays converge. The nature of this real image varies depending on how the light travels through the lens. As we learned in class, and like we proved in the physics lab, the angle of light entry changes depending on how far or how close the object is from the lens. But we need to remember that the lens can only bend the light beam to a certain degree, no matter how it enters. Also, we need to remember that from a closer point a light beam converges at longer distance from the lens. To make more clear, the real image of a close object forms farther away, than the one of an object that is at a longer distance. This is what we cause when we turn to zoom in and out with the lens of our cameras to focus on a specific object. Then to capture the image the camera creates a chemical reaction using the film (old cameras) or by using electricity (digital cameras).

2011-11-30T17:59:00.001-08:00

Superconductivity

Kyshalee Vázquez

In most futuristic movies we see objects or transportation devices that hover over the ground, such as trains, cars and even skateboards. This was thought as one of the impossible creations of science fiction; nonetheless this could be made possible through the superconductivity phenomenon. However these are not the only cases in which superconductivity can improve our daily lives. But first let us discuss what superconductivity is.

Nobel Prize winner, Heike Kamerlingh Onnes in 1911 was first to observe the phenomenon in which the electrical resistance of numerous metals and ceramic materials dramatically drops to cero, when its temperature reaches its critical points. This phenomenon was named superconductivity, most probably for its lack of resistance to electrical conductivity. This happened when Onnes cooled mercury to the temperature of liquid helium, four degrees Kelvin, and its resistance disappeared unexpectedly. Later in 1933, Walther Meissner along with Robert Ochsenfeld noticed that materials in their superconductive states will repel magnetic fields and thus repelling the magnet. This effect was named the Meissner effect. Therefore the loss of all electrical resistance is not the only feature that distinguishes the phenomenon, for the Meissner effect also characterizes superconductivity. The Meissner effect happens when a material does not interact or excludes magnetic fields from its interior, behaving like a perfect diamagnet. Because of this effect, if you were to put a magnet on a material in its superconductive state, the magnet would hover over the material without falling until the material is no longer in its superconductive state. This happens because the magnetic field of the magnet is not able to interact with the inside of the material, expulsing it outward and thus making it hover. As a result from this vehicles of transportation can be optimized in ways we thought impossible or too far away from our technology, just by applying this phenomena.

The problematic part of this wonderful discovery is that the material’s temperature has to reach its critical point, which is usually very low. This is usually achieved by the use of liquid nitrogen, which is quite accessible, but a slight disturbance of the process; clearly because it would be ideally best to reach super conductivity at room temperature. Some critical points are extremely low temperatures such as less than 1 K and others can be as high as 125 K. Superconductors have been categorized in type I and type II, mostly depending in the critical point’s temperature of the material. Type I superconductors are pure metals characterized by no electrical resistivity, no internal magnetic fields and can be explained by the BCS theory, named after John Bardeen, Leon Cooper and Robert Schrieffer, which describes the act of electron pairs as bosons. On the other hand, type II superconductors are made from alloys, mechanically harder and depict much higher critical magnetic fields.

Many technological advances and discoveries have been made during the last century, but there is so much more left to uncover. The future of superconductivity lies in the simplification of the application of this phenomenon in our daily lives. To achieve the upmost simplification it would be ideal to find another way to cool the material or a material which can be superconductive without cooling it. If this were to happen, the electrical systems in houses and cities would be even more efficient. Our mediums of transportation could be completely revolutionized, by the decrease of our dependence of petroleum.

Bibliography

"Superconductivity." Hyper physics. Web. 15 November 2011.

"Superconductivity." The teacher’s web. Web. 20 November 2011.

"What is superconductivity?" Howstuffworks. 7 May 2009.Web. 17 November 2011.

2011-11-30T17:39:00.001-08:00

How the Aurora Borealis is formed and why it occurs in diurnal period?

Amarillys Avilés Miranda

The aurora borealis is produced by of the oscillations and disturbances of terrestrial magnetism. It is caused by the collision of energetic charge particles with atoms in the high altitude atmosphere (Arctic and Antarctic regions). The sun, which has a lot of particles at 40,000 ⁰C and enormous pressure make the aurora effect. The light makes the particles inside of the sun to move to the surface creating the electrical current charged gas that makes a magnetic field inside. In some places strong magnetic field pushes the wave trough the surface making a band. When the band breaks, causes a solar storm. This storm travels until it arrives to the planet Earth where the aurora effect is created when the particulate collide with terrestrial magnetism. This effect makes a wonderful spectrum of colors in the sky.

Our magnetic field is originated by the liquid metal movement and it extends a lot of miles far away from Earth. It's movement is undulated through the meridian line with South and North dipole like it is shown in the figure in the left. The solar storm tries to enter the surface but the magnetic field of the Earth breaks it. At this breaking point the particles collide with different gases of the atmosphere and create the colors that we observe. The effect is frequently produce at the Earth's poles because the rays of the aurora are oriented along the line of the force of the magnetic field.

A previous study of the cathodic phenomena tries to explain the diurnal period of the aurora borealis. The author thinks that the aurora borealis: is caused by cathodic phenomena produced in the atmosphere under the action of the Hertzian wave emanating from the sun. This is because the greatest frequency of the aurora coincides with the greatest frequency of the sun spots in one decennial period, which seems to correspond with the period of synodical rotation of the sun (regions of maximum activity of the sun). This theory explains that the diurnal period of the phenomenon that occurs by the maximum production should correspond with the maximum of solar radiation in a given point. The apparent maximum of the aurora cannot be observed until the early hours of the evening, in accordance with experimental facts, this is because the brilliancy of daylight at the instant of the real maximum will hide the phenomenon.

2011-11-30T17:32:00.001-08:00

Rotational Doppler Effect

Angelica M. Cortes Velez

The article “Like a speeding watch” is about the rotation in lights electric field vector, that can alter the lights frequency. It has been spotted in the laboratory, that this rotational is the equivalent of the Doppler effect. The author of the article was, Miles Padgett, his report

“Physical Review Letter”, with Barreiro and colleagues have measured the broadening of a spectral line caused by an effect analogous to the conventional Doppler Effect.

Talking more about Miles Padgett, him is a Professor of Optics in the Department of Physics and Astronomy in the University of Glasgow. He heads a 15-person team covering a wide spectrum from blue-sky research to applied commercial development, funded by a combination of government charity and industry. In 2009 Padgett was awarded the Institute of Physics, Young Medal "for pioneering work on optical angular momentum".

Padgett has an international reputation for his contribution to the fundamental understanding of light's momentum, including conversion of optical tweezers to optical spanners, observation of a rotational form of the Doppler shift and an angular form of Heisenberg's uncertainty principle.

The Doppler shift or Doppler effect is the change in frequency of a wave for an observer moving relative to the source of the wave. Doppler first proposed the effect in 1842 in his treatise “ On the coloured light of the binary stars and some other stars of the heaven”. The hypothesis was tested for sound waves by Buys Ballot in 1845. The Doppler effect is used in some types of radar, to measure the velocity of detected objects.

The shift in frequency of this case arises from rotation. The effect was observed in terms of Jones polarization matrices, wich describe this effect in a medium with an orientation of the electric field. The electric field depicts the force exerted on other electrically charged objects by the electrically charged particle the field is surrounding.

Polarization (also polarisation) is a property of certain types of waves that describes the orientation of their oscillations. Electromagnetic waves, such as light, and gravitational waves exhibit polarization; acoustic waves (sound waves) in a gas or liquid do not have polarization because the direction of vibration and direction of propagation are the same. By convention, the polarization of light is described by specifying the orientation of the wave's electric field at a point in space over one period of the oscillation. When light travels in free space, in most cases it propagates as a transverse wave—the polarization is perpendicular to the wave's direction of travel. In this case, the electric field may be oriented in a single direction (linear polarization), or it may rotate as the wave travels (circular or elliptical polarization). In the latter cases, the oscillations can rotate either towards the right or towards the left in the direction of travel. Depending on which rotation is present in a given wave it is called the wave's chirality or handedness. In general the polarization of an electromagnetic (EM) wave is a complex issue. For instance in a waveguide such as an optical fiber, or for radially polarized beams in free space, the description of the wave's polarization is more complicated, as the fields can have longitudinal as well as transverse components. Such EM waves are either TM or hybrid modes.

In many areas of astronomy, the study of polarized electromagnetic radiation from outer space is of great importance. Although not usually a factor in the thermal radiation of stars, polarization is also present in radiation from coherent astronomical sources (e.g. hydroxyl or methanol masers), and incoherent sources such as the large radio lobes in active galaxies, and pulsar radio radiation (which may, it is speculated, sometimes be coherent), and is also imposed upon starlight by scattering from interstellar dust. Apart from providing information on sources of radiation and scattering, polarization also probes the interstellar magnetic field via Faraday rotation. The polarization of the cosmic microwave background is being used to study the physics of the very early universe. Synchrotron radiation is inherently polarised. It has been suggested that astronomical sources caused the chirality of biological molecules on Earth. The rotational Doppler effect is interesting because here the spin and orbital components are indistinguishable. Instead the total angular momentum of the light beam, that is crucial.

2011-11-30T17:29:00.001-08:00

A Life Without Gravity

Alexander Rivera

Do you ever think what could happen if we woke up one day and were no gravity? Before start, we must understand what gravity is. Gravity is an attractive force between any two atoms. The more matter, the more gravity. Things that have a lot of matter such as planets and moons and stars pull more strongly. Mass is how we measure the amount of matter in something. The more massive something is, the more of a gravitational pull it exerts. The perfect example for this is when we walk on the surface of the Earth, it pulls on us, and we pull back. But since the Earth is so much more massive than we are, the pull from us is not strong enough to move the Earth, while the pull from the Earth can make us fall flat on our faces. In addition to depending on the amount of mass, gravity also depends on how far you are from something. This is why we are stuck to the surface of the Earth instead of being pulled off into the Sun, which has many more times the gravity of the Earth.

Knowing the definition of gravity, we may ask what if doesn’t exist? A lot of people when first think if there were no gravity, the first thing in their minds is that everything including us is going to float. That’s true but the thing is that imagine cars, humans, animals, furniture and many others floating, is going to be a mess. But that’s not all, two essentially things in our life are going to disappear: water and air. The air depends of our atmosphere, and the atmosphere depends of gravity, what means that in a life without gravity there was no atmosphere. The air will escape into the space leaving us without oxygen. Like the air, the water of the earth is going to be boiling in the space. We were living in a world without air to breath and no water to hydrate. Without gravity no one can live. If it were possible to adapt ourselves to an environment without gravity it is going to be a boring one. We cannot exercise ourselves, there were no sports, no nothing. Another thing is that we are going to be skinniest. Our muscles and bones will deteriorate, they are going to be useless.

Never can we ask a life without gravity because it can’t be possible and can be dangerous for each living thing on the planet. So when you think that this constant (g= 9.81m/s^2) bothers you because makes you slower and lazy, and sometimes limits you to do such things, think that this constant is essentially in our lives. We cannot live without it, and we can't afford to have it change. Gravity is a very important constant in physics, but it is an essentially true constant of our lives that will be with us for our rest of our lives. No better life than a life with gravity.

2011-11-30T17:12:00.001-08:00

How a Physics Class changed the way I See Things

Victor M. Estremera

I’ve always been curious to know how things are made or how they work, which is why I decided to study Mechanical Engineering. When I started College, I was looking forward to my Major Courses, but wasn’t too thrilled about Physics I & II because I couldn’t find a relation between Physics and Engineering.

As much as I enjoyed watching TV shows that explain how machines and Manufacturing Plants operate from an Engineering point of view, I couldn’t understand why Physics I & II were so important in my curriculum. It wasn’t until I started taking Major Courses such as Thermodynamics, Electric Circuits and Fluid Mechanics that I understood how Physics is associated with Engineering. Physics is the base to Engineering, regardless of the Engineering Specialization.

For example, Civil Engineers couldn’t design a bridge without understanding Newton’s Laws of Motion from Physics I. The Second Law states that F = ma. The Third Law states that the mutual forces of action and reaction between two bodies are equal and opposite. That’s why in Statics, combining these two laws, the sum of the forces acting on the bridge must be zero in order to stay fixed. Chemical Engineers wouldn’t be able to solve problems of Physical Chemistry and Thermodynamics without understanding topics from Physics I such as the Ideal Gas Law or The Kinetic Theory of Gases.

Electrical Engineers could never design an integrated circuit without the combination of Ohm’s Law and Kirchhoff’s Voltage and/or Current Laws from Physics II. Kirchhoff’s Current Law states that the algebraic sum of currents in a network of conductors meeting at a point is zero. This is the principle of Conservation of Electric Charge. Kirchhoff’s Voltage Law states that the algebraic sum of voltages in a closed loop is zero. This is the principle of Conservation of Energy.

Mechanical Engineering is perhaps the widest branch of Engineering and contains endless principles from Physics I. Designing an Internal Combustion Engine wouldn’t be possible without the Laws of Thermodynamics and the Ideal Gas Law. Improving the efficiency of the engine couldn’t be done without the model of the Carnot Cycle.

Designing a submarine wouldn’t be possible without Archimedes’ Principle. This principle states that any object, wholly or partially immersed in a fluid, is buoyed up by a force equal to the weight of the fluid displaced by the object. In other words, the Buoyancy exerted on the submarine = the displacement of the water. And once again, Newton’s Laws of Motion come in to play. When it comes to the Design of a Mechanical System or Machine Component, the Second Law is used to analyze dynamic loading. The list goes on.

We can see that the most basic equations of Physics are responsible for some of the most incredible achievements in Engineering. From this perspective, we could say that Engineering is a branch of Physics or, furthermore, an application of Physics, because Engineering wouldn’t exist without Physics.

2011-11-30T17:03:00.001-08:00

Capillary Action

Angel Lugo Lugo

I would like to discuss something that was not explained in our course but always had my attention. Since I was a kid I had a lot of curiosity about why when I had a straw in a glass with liquid I always observed that the level of the liquid was a little higher inside the straw. Now that I studied physics and as a university student I am able to do research and learn about why of the phenomena I know this is called capillary action.

The capillary action can be observed first of all in a capillary tube and laboratory glassware forming a meniscus. This is caused by adhesion, which is the attraction between different molecular species, when it pulls the liquid column up until there is a sufficient mass of liquid for gravitational forces to overcome the intermolecular forces. After some research I learned that the capillary action is not only present in tubes, I did learned that this is the way tears comes out when we cry. This is because inside our eyelids we have the lacrimal ducts which are of very tiny diameter, then acting as capillary tubes. This is also observed in paper towels, sponges, fabrics, well in most of the material which are sufficient porous to absorb liquids. This characteristic of the materials is even used for chromatographical separations of liquid and gases in chemistry and physics laboratories.

But then I asked myself: It has to be physical explanations which allow me by some sort of equation describe the capillary action. Well I founded an explanation for my beloved liquid inside the straw and why depending the wide of the straw varies the level of the liquid inside it. The height h of a liquid column is given by:

where gamma is the liquid-air surface tension (force/unit length), θ is the contact angle, ρ is the density of liquid (mass/volume), g is local gravitational field strength(force/unit mass), and r is radius of tube (length). Another thing I really found as a curious detail when I got in a chemistry laboratory is the upside down meniscus of the mercury. After researching about it I found it was because of the polar surface in contact with.

As for the another applications of capillary action that I mentioned before I founded that there is also a physical description of the volume of liquid absorbed by the porous material. A porous material absorbs liquid by a rate that decreases over time, in other words as more time passes less liquid will be absorbed due saturation of the media. The volume absorbed is described by the following equation

where S is the sorptivity of the medium, with dimensions m/s1/2 or mm/min1/2 , A is the area of the porous object and V is the cumulative volume. The sorptivity of the material is mainly given by tables. So if you can do some research of the porous material you are using, calculate the area of the piece of material being used you will be able to know how much liquid will by absorbed by it.

I found this topic quite interesting and useful in the today’s industry, and very practical and favorable in laboratories technology.

2011-11-30T16:50:00.001-08:00

Through the Wormholes

Jonathan A. Varela Escapa

One night I was seeing a program on T.V. of the wormhole and I became so intrigued of it to learn more about it. The wormhole definition is a theoretical entity allowed by the Einstein’s theory of general relativity in which space time curvature connects two distant locations.

The Einstein’s theory of general relativity also known as the Einstein-Rosen bridges, described by the formula:

In which it describes that the wormhole connects in different parts of space in time.

The Einstein-Rosen mathematically wormhole was derived by the study of black holes, in which a black hole is a region of space time from which nothing, not even the light can escape from it. Einstein’s theory for the wormhole was never intended as a tool for space travel, it was theoretically created at some moment of time in which it will open up briefly then it will close, and anything that tries to pass through it will get crushed when it squeezes apart, so therefore this is not a traversable wormhole, and what we are looking is for a traversable wormhole.

The typically of wormhole that a scientist writes down in equations and studies is very unstable and will vanish in an incredibly short amount of time, and what we want that it stays open so we can theoretically travel through time, therefore we need something to let it open. For a wormhole to be kept open, it requires something called exotic matter or negative matter, we have never seen negative matter before, and this type of matter will have anti gravitational properties. The possibility of a traversable wormhole was first demonstrated by Kip Thorne and his graduate student Mike Morris in 1988, the type of traversable wormhole that they proposed, was held open by a spherical shell of negative matter, and it is referred as the Morris-Thorne wormhole. There have been other theories such as the Matt Visser and the Gauss-Bonnet theory.

The theory of general relativity predicts that if a traversable wormhole exists, this would allow travel in time and space, because the wormhole connects two points in space-time. A traversable wormhole could be used as a time travel machine, and this could be accomplished by accelerating one end of the wormhole to a high velocity relative to the other, and then sometime later bringing it back, this would cause a relativistic time dilation and would result in the accelerated wormhole mouth aging less than the stationary one, but time connects differently through the wormhole than outside it. Therefore synchronized clocks at each mouth will remain synchronized to someone traveling through the wormhole itself, no matter how the mouths move around. This means that anything entering the accelerated wormhole mouth would exit the stationary wormhole mouth at appoint in time prior to its entry or the same age that the accelerated end had been at the moment before entry.

There is still much speculation on whether it is possible for wormholes to actually exist and, if so, what properties they would actually possess. In conclusion, we can say that the wormhole is a system in which something can travel through time and space; in a very distant future we may really discover the facts about the wormhole, and it may be used as a time travel subway through the universe.

2011-11-29T17:34:00.001-08:00

Quantum dots, a New World of Study

Emmanuel J. Chamorro Rivera

In chemistry there are new discoveries, among them is the existence of quantum dots, they are semiconductor compounds too large to be atomic and too small to be colloids. These compounds are unique in their use, from optical wavelength change to sensitization of stable and high-speed lasers. For many scientists the study of these compounds is vital to discover new possibilities in many field of study. These are capable to change the color that they have when they are shot with an Ultraviolet light, the colors depend on the quantity of the particles in a given solution. As we may know from physics when light passes from one medium to another the characteristic of wavelength and speed change but never does the frequency, but what happens with the quantum dots? Because of their characteristics they can change which type of frequency they absorb, and which they leave untouched; a property that we have seen in the sleet experiments, but in a quantum scale, this causes the solution to change the color, in other words, the frequency, leaving the wavelength intact. This causes the brightness of the color to be the same but the color to be different.

Now many would think that this is unimportant to fields like physics, but if we were to analyze what it means to be able to chose a wavelength and maintain it through a medium, means that we could break the principle that the frequency may not be changed. As many know the frequency is one of the properties of light that remains constant, but quantum dots can change this. This means being able to build a laser that can emit the wavelength in a stable manner, chosen by the scientist. The only thing to be change is the array of quantum dots used to change the wavelength. Why is this important in physics? This means that if a laser with incredibly high energy, a respective quantum dot can be used to manipulate the levels of energy when changing the wavelength. This small particles act as wavelength manipulators, because it is easy to change the wavelength by only changing the quantity and array of quantum dots.

The characteristics that make this effect of quantum dots possible have to do with something physics study, charges and electric fields. It is well known that atoms have both positive and negative charges; a quantum dot has an array of two elements bonded into each other. The electrostatic forces between them cause many sub-atomic particles to move, and to cause partial charges from time to time. When more quantum dots are added, they interact because of the partial charges, then the particles arrange themselves in different patterns, these patters change the properties of light entering this medium.

In science discoveries are found every day, these discoveries may change our perspective of how the world works. Quantum dots have created a new field to be studied; many are trying to discover the hidden potential of these particles. Even small particles can create change, and worlds to be discovered.

2011-11-29T17:19:00.001-08:00

Magnetic Monopoles, Theory or Truth?

Paul Feliciano Abreu

We live in a world surrounded by enigmatic phenomena. One of the most present phenomena is the asymmetry that we find it in the magnetism and in the electricity, by that; there are no magnetic charges that can be compare to electric charges. A thing that is always there around us is the electrically charged particles like protons and electrons but nobody talks about an isolated magnetic charge, if something would have this charge will be the magnetic monopole. For this idea we will use a magnetic bar with a north pole and a south pole and cut it by half, next we will have two poles isolated but this thing will never be possible or if its possible is in just a rare occasion because the nature does not create magnetic monopoles, they can just be imagine and related to some idea like comparison, but this would not be a thing to stop studying or investigate them, because I think this could be found sooner or later.

Picture of how should be form the magnetic monopoles

By other hand, we have electric monopoles that are electric charge particles very abundant in matter because every piece of it has a big number of electrons and protons that are authentic monopoles. But in the magnetism we cannot see this phenomenon because there do not exist nothing similar to electric monopoles but it should be interesting to find a case. The electromagnetic theory unifies the electric force and the magnetic force, because the electric charges work for both forces, in the electric force they generate the force and in the magnetic with the movement of the particles the magnetic force arises. An example of what could be a magnetic monopole is if we took a magnet bar really thin and about 1 kilometer of distance with a magnetic field at each end of the bar, because the ends are really separated and the bar is so thin that the lines of the magnetic field don’t surround the end of the magnet the unify in the bar creating a way back to the other end or creating a cord with a radial field (Dirac’s cord) or something like it. Going to Dirac’s theory he just wanted to explain the behavior of the relativistically moving electron, and so to allow the atom to be treated in a manner consistent with relativity. And for this theory he apply the next equation:

where

m is the rest mass of the electron,

c is the speed of light,

p is the momentum, understood to be an operator in the sense of the Schrödinger theory,

x and t are the space and time coordinates,

ħ is the reduced Planck constant, h divided by 2π.

Dirac strings or cords

After Dirac’s theory was proposed, physics accept the possible existance of magnetic monopoles. If these magnetic monopoles exist they will be producing a magnetic force, and also by their movements they could gain electric force. As a matter of fact these monopoles could be a great help to the universe density.

News of magnetic monopoles detected in a real magnet:

From: Science Daily webpage in Sep 03 2009 http://www.sciencedaily.com/releases/2009/09/090903163725.htm

2011-11-29T11:53:00.001-08:00

Usefulness of Magnets

Arnaldo López Rivera

When I was younger I was intrigued by magnets, even though I never understood how they worked in a deeper level. All I knew was that magnets attract each other based on their polarities, in that opposites attract while same polarities repel. After reading and taking a few physics and engineering courses I have found many diverse uses for magnets, besides hanging up papers in the refrigerator. You may wonder. What are magnets useful for? The answer is magnets are useful in a wide variety of areas, such as medical equipment, electronics, and transportation.

For starters in the medicine field, most magnets are used for the diagnosis of medical problems, such as physical and organ function. Some of the equipment that use magnets are MRI, hearing aids, x-rays, and VCD. In MRI (Magnetic Resonance Imaging), uses superconducting magnets to form images of the inside of a human body. While hearing aids use magnetic fields to increase the ears ability to hear. And finally there’s a VCD which uses a magnetic rotor, in order to pump blood and aid those with failing hearts who cannot afford a heart transplant.

However the are where magnets truly shine is in electronics. First, without them televisions would not work. The reason for this is because there are magnets inside the cathode ray tubes, which deflect electrons towards any region allowing us to see the images on the screen. Secondly without them all of our media carrying devices would have nowhere to store the information, such as IPODS, PS3, XBOX, PSP, computers, etc. The reason for this is because hard drives use magnetic fields in order to read and/or write data (which is also known as magnetic reading). It is possible to see the effects of magnets on electronics, for example if you put a magnet against an old computer, the screen would crash or if you’d put it against a floppy disk, all the information would be erased.

And lastly magnets can be used in the transportation industry. For example in cars magnets can be found throughout the whole car, such as in the motors, the electric window motors, are in the alternator. The alternator uses a magnetic field in order to convert the mechanical energy put into the motor into electrical energy. Another example of transportation, is in roller coasters, magnets are used to cause a propulsion at the start of a ride usually; and they’re also used to gradually slow down a roller coaster, making them a cost effective method for brakes.

Magnets have a wide variety of uses, ranging from a refrigerator magnet to a motor, and a media storage device. They are of high importance in today’s society, which relies heavily on technology. Without magnets we would not have a means for transportation, since most motors, if not all use magnets. We would also not have many of the electronics we use in our home every day, such as computers, and gaming devices, because we would have no way to store all the programs in order to make the device work efficiently. In retrospect today’s society has come a long way thanks to the usefulness of magnets.

2011-11-29T11:38:00.001-08:00

Neutrino: Faster Than Light?

Rubén D. García Avilés

When I heard the news that there was a particle that runs faster than light and that Einstein may be wrong I was shocked. A group of physicists were doing some measurement with neutrinos and developed then using a particle accelerator at CERN.

This has been widely reported as being the end of relativity, but this is not the case at all. Neutrinos are interesting little neutral particles according to literature that have almost a mass of zero. Knowing their nature, they can go through matter without being absorbed, going faster. The time of traveling of the neutrinos was measured with extreme precision and caution using GPS timing signals and a cesium atomic clock.

The speed of neutrinos was measured and compared to the speed of light by simply subtracting the expected time of light to travel with the distance from the time that the neutrinos need to travel the same distance. The expected was zero for traveling at speed of light and a negative value for any below speed of light, but it presented a positive value of 60.7 nanoseconds causing some intrigue in the science world. The final paragraph of the report shows:

This is very important because the physicists established that no conclusion could be drawn without more experimentation. The shocking part is that the measurements were using some of the most amazing and precise instruments and techniques ever created. No matter what is found to be the actual cause of this 60.7 nanoseconds variation, the conclusion that you can draw is that it’s an amazing time in history were such measurements can be made, and an exciting time to be a practitioner or admirer of science.

As discussed in class Einstein is one of the greatest minds in history. He developed the equation E=mc2 and established that nothing could travel faster than light which has a speed of 3.00 x 108 m/s. All of this was established around 1904, Would be true that 107 years later in our world history recent scientists demonstrated that the Einstein, Newton, Volta and others were wrong on their postulates? The answer is No, because these great people established their thoughts with the knowledge of the era, they developed theories that transformed human history, having in mind that it’s not for the little error that some men believe but maybe they forgot to create an equation able to classify everything. Our world is a world of changes that will be responsible of transforming the laws of some of the world’s greatest men in history.

The future generations of young scientists who are sitting on a classroom with many ideas running through their minds and the interesting’s findings that they will had to contribute and make a world better. “Einstein wouldn’t be disappointed by these findings; he would be intrigued and proud to see the legacy of great science continuing forward’’ leading a group of scientist to appreciate his findings make a revolution in world.

Bibliography:

¿Puede un neutrino acelerado refutar a Einstein? - WSJ.com. (n.d.). Retrieved November 27, 2011,from http://online.wsj.com/article/SB10001424052970204831304576596823787257198.html

Neutrinos and the Speed of Light — A Primer on the CERN Study | GeekDad | Wired.com. (n.d.). Retrieved November 24, 2011, from http://www.wired.com/geekdad/2011/09/neutrinos-and-the-speed-of-light-a-primer-on-the-cern-study/

Physics shocker! Neutrinos clocked faster than light | Deep Tech - CNET News. (n.d.). Retrieved November 24, 2011, from http://news.cnet.com/8301-30685_3-20110594-264/physics-shocker-neutrinos-clocked-faster-than-light/

What’s a Neutrino? (n.d.). Retrieved November 24, 2011, from http://www.ps.uci.edu/~superk/neutrino.html

2011-11-29T11:30:00.001-08:00

An Introduction to Antimatter

Benedict D Newball Diez

In my article I would like to talk about a subject that has not been discussed in our course of FISI 3172. I would like to talk about antimatter, some of its potential uses and give some opinion as to how it could be used and why we are not using it right now.

I should start by giving a brief description of what antimatter really is. We could start by remembering solving a quadratic equation you always would get two answers a negative and a positive. Well antimatter is precisely the exact opposite of matter. A funny way to look at it would be taking matter and multiplying it by negative one. What this means is that the anti-proton would have a charge of –e and the anti-neutron has a charge of e. Everything with the same mass. There is very little antimatter in the universe; this is known because when it comes into contact with regular matter they annihilate each other, releasing a lot of energy sometimes in the form of gamma rays that would be detectable. Because of this the formation of antimatter requires vast amounts of energy.

Antimatter is made where there are high-energy particle collisions. Artificially these can also be produced with highly advanced equipment that requires a vast amount of energy and even more funding. One of the most important creations related to antimatter would have to be the anti-hydrogen atom which was created in an experiment using a Low Energy Anti-Proton Ring (LEAR). This was an experiment designed to decelerate and store the precious antimatter, study the properties of it and create antihydrogen atoms. This experiment was made in 1982 and in1996 was converted into the Low Energy Ion Ring (LEIR).

Antimatter has the potential to be the primarily energy source in the world. One of the most extraordinary uses would have to be its ability to provide fuel for interplanetary travel for space ships. It would be called antimatter catalyzed nuclear pulse propulsion. This type of energy would be a lot more useful than regular energy. Studies have shown that antimatter has ten times the energy per unit mass that the conventional chemical energy that is typically used is space travel. Another amazing fact about antimatter energy is that it is not only more efficient than chemical energy but it has been calculated that the use of this energy source has about 3 times more energy per unit mass than the energy that would be produced by a nuclear fission and 2 times as much energy as a nuclear fusion!

As a mechanical engineer major I must admit I get blown away by all the potential this type of energy has. It is said that a very small amount of antimatter could power a city for a very long time and that a gram of it could run your car for 100,000 years! This has the potential to grant us victory over the long fought light-speed battle we faced when traveling in space. It is obvious to say that this type of energy represents the future and in my opinion should be dealt a lot more importance in the research and development programs.

On the down side with our technology as it is we might be very far away from achieving this utopian idea. The cost of development alone has put a stomp on the research and development of this energy. Another pessimist way to look at this situation is the corruption of man-kind and the fear of this energy being used for bad and not peaceful porpoises. Exactly what happened with nuclear technology.

I for one choose to stay on the optimist side of the situation hoping for one day in which I will be dealing myself with this type of technology. Because with modern advances these days you’ll never know what will happen tomorrow. That is my take on antimatter I hope that you have enjoyed it.

2011-11-26T18:01:00.001-08:00

Superconductivity

Juan G Perez Narvaez

Not so much ago I saw a video of quantum levitation. The video was very interesting and I wanted to know how that was possible. When I looked this was possible by a phenomenon known as superconductivity. Superconductivity is a quantum mechanical phenomenon in which there is exactly zero electrical resistance. This was discovered by Heike Kamerlingh Onnes.

What happens is that when a superconductor is cooled below its critical temperature is resistance drops to zero. This means that if we put an electric current in a loop of superconductive wire in a temperature lower than its critical temperature the current will continue flowing indefinitely with no power source. For normal conductor even when the temperature is near absolute zero there exists some resistance in them. In superconductor there is none at all. But the part that I want understand is why do the material levitate and stay locked in an specific point in space. And for that we look at one of the things that characterize superconductivity, and that is the Meissner effect.

The Meissner effect is the expulsion of a magnetic field from a superconductor during its transition to the superconducting state. In a superconductor above its critical temperature the magnetic field goes completely through them, but in a superconductor below its critical temperature the magnetic field does not go through it. It surrounds it and locks it in space.

In the pictures above we can see how the magnetic field distributes when the superconductor is above or below its critical temperature. We see that the field won’t let the superconductor move from where it is, unless we apply a force greater than the one generated by the field.

But what would be some uses for this discovery? In the field of levitation the superconductors are very useful. For example in transportation like trains extremely powerful conductors may be used to make train practically float and therefore eliminate friction between the wheels and the track. In medicine they use superconductors in MRI (Magnetic Resonance Imaging) for example. In Korea they have developed the Superconducting QUantum Interference Device that is capable of sensing a change in a magneticfield overa a million time weaker than in a needle in a compass. That is as little as e-14T. This means that people would not have to be exposed to strong magnetic fields. Also superconductor a can be used in generators instead of using copper wire and other materials. This way the efficiency of the generator would be 99% more than the generator of copper wire, etc. In the military one of the uses of superconductor are in the deployment of “E-Bombs”. These bombs use superconductor to create a high intensity electromagnetic pulse to destroy enemy electrical equipment. These is better known as an EMP.

There are a lot of other uses for superconductors and with time there will be development of the uses of a superconductor. At first I only knew that the superconductor only where user to levitate, but know I know that there are a lot of uses for this phenomenon. And the uses help a lot the entire humanity.

2011-11-26T17:16:00.001-08:00

Our Big Problems, Solved by Small Atomic Structures

Alexander Millet Ayala

We currently have a worldwide problem with our energy usage making the earth taking more contaminants in the atmosphere, contributing to what we call global warming. We depend on power plants to power our houses and household appliances to make our lives simplified. Power plants may be a thing of the past with recent inventions in nanotechnology. Solving the problem requires different types of materials with different uses. Let’s start with the carbon nanotube polymer, which acts like a polarizer when the person needs it. The material is done by vaporizing graphite, turning it into a mesh nanotube and then adding it into a flexible plastic that can be normally seen through, and the light will pass through. The special thing about this material, is that with a minimal electrical charge (2 volts), it will turn colored, and reflect the light trying to cross over the material. Some applications for this is the difference of sun intake on different seasons, turning it on to make the room colder on summer, off when you need the room warmer on winter, and it would also work as a privacy filter. This would save energy in winters by efficiently changing the light and heat into the room, and not the thermostat.

An illustration of the mesh nanotube that would be used.

But what about the energy, how can we get clean and easy energy? The answer is also in nanotechnology, by combining two different kinds of nanomaterials, a detector and imager that turns infrared waves at day, or night, and turns into electrons, which can be stored or used at the moment. Electrons, as discussed in class, are the elemental particle which makes electricity possible when it flows through a medium. This makes obtaining energy in a continuous way, even at regions with low sunlight. The great thing about this material is that it is also a transparent material that can be used with the carbon nanotube polarizer. Combining these two materials can make any window be an efficient energy generator, and energy saver. So, now what is missing is a battery to hold the electrons, which are now being built and tested with various nanomaterials in the University of Texas. These batteries are the last component to the plan, because what’s the use of energy if you cannot store it for when it is needed? These are needed to hold those electrons obtained by the nanomaterials, and release them when needed in the most efficient manner, while occupying a relatively small space.

A sheet of the nanomaterials in a flexible plastic polymer.

This can change everything and eliminate our dependence on fossil fuels. We could power cars, planes, houses, buildings, etc. with the stored energy in the batteries. This also solves problems in third world countries that need electricity, and clean water. Animals also could benefit too, since the other clean renewable methods of energy have the problem that it could destroy their ecosystems. Examples with this are natural gas, which can poison water or even explode in the event of a leak, and eolic energy windmills that could destroy bird nests. With free energy, the next generations could have the opportunity to have better human conditions and a cleaner world.

References:

“The Future of Nano-Electric Power Generation”. Sunlitepower.org. Web. November 11, 2011. November 24, 2011.

Additional resources:

http://www.ted.com/talks/justin_hall_tipping_freeing_energy_from_the_grid.html

2011-11-22T18:18:00.001-08:00

Magnetic Monopoles: A feat yet to be reached

Jan K Huertas de la Cruz

Magnets are one of the earths most studied phenomena. Why? Is one of those natural marvels that make our twentieth first century what it is today, a marvelous age in the advancement of technology. And even more, it is an occurrence that helps the earth to be habitable, it produces a magnetic field which without it we couldn’t live on earth and just for us to enjoy it is thanks to it that the beautiful Aurora happens. But why from a most studied phenomenon, the magnets, can’t we get monopoles? This question has baffled the minds of geniuses for centuries and it is the main argument in this essay.

According to different researchers and scientists a magnetic monopole is “a hypothetical physics particle with only one magnetic pole.” In other words, when we have a magnet we normally have two "charges", a north pole and a south pole, which means that overall, the magnetic charge of the magnet cancels out. To better understand the magnetic charges of a magnet we can use the magnetic field as an example and here is a diagram.

In the pictures above we can see a magnet bar with both its north and south poles, and the diagram of the magnetic field it produces.

Everyone knows that the north and south poles are attracted, but why is the question many people have in their minds. When the magnetic force exits from the north pole it begins to weaken, so naturally when it starts weakening it feels attracted and controlled by a stronger force which is the south pole, so eventually this force starts to deviate from its straight course and starts moving to the south pole. This is what we can see in the picture in the right.

But the question we want to answer is why we can’t have magnetic monopoles. There are many theories as to why, and what I’m going to do is explain the why as I understood it. Let’s begin the explanation by making an analogy. Let’s say that the bar magnet is a water hose and that the water is the magnetic field it produces. Looking at the picture, and knowing how a water hose works, we can say that the water enters from the south pole and exits the north pole. But what would happen if we cut a hose in half, one of those halves is going to stop throwing water since by basics physics we know that for water to exit the hose first water must enter the hose. One can’t just cut the hose in half and expect it to keep throwing water from the 2 halves.

Well, this basic understanding can also be applied to magnets, if we cut a magnet in half, the “force” must exit from one side and enter from the other one. One can’t just cut it in half and expect a constant force to keep acting by its own, like the water hose. Many scientists have conducted many experiments and researches such as the string theory trying to explain the possible existence of magnetic monopoles, but we are yet to see such thing.

This is a basic explanation as to why magnetic monopoles can’t be produce nowadays. Even though we have many theorists claiming that they can be manufactured we are yet to see this happening. But as for now let’s keep in mind that magnets are here for a reason, and the main reason I can think of as to why they exist, is that without them we wouldn’t be able to live on earth, so as for now let’s just keep enjoying their benefits.

References:

• Giancoli, Douglas C. Physics for Scientists & Engineers with Modern Physics. 4th ed. Vol. 1. Upper Saddle River, N.J: Prentice Hall, 2009. Print.

• "Magnetic Principles” Magnetic Research and Development. (Physics)Network. Web. 22 Nov. 2011

2011-11-19T13:33:00.001-08:00

Life without Electric Current

Natalie J. Aponte Méndez

Today our lives are based in technology, electric devices, internet and others sources that simplify and gives to the human race the ability to control and adapt to their natural environments. The global economy depends of technology and countries around the world use spaceships and some other technological devices to investigate new alternatives and to discover new physics laws. Think about how much we all depend on technological products and the times you use technology each day. In the past Newton discover important laws and in the 1800 Alessandro Volta invented the first electric battery and produced the electric current without technology. How we can reduce this terrible dependence of technology?, What happened if we reduce the amount of electric current consumption? Thomas Alva Edison in 1879 invented the light bulb a historical important device that uses electric current to maintain our houses illuminate in the night. The light bulb is an electric lamp in which a filament is heated to incandescence by an electric current. It is possible to create a light bulb without electric current passing through it?

We learn about circuits to complete the charge flow and the different forms to connect a light bulb or any other device. But it is time to create a new alternative to illuminate our world, a new light bulb that reduce or eliminate the current consumption, light bulb created by WATER. Water covers 70.9% of the Earth’s surface and is a natural source. This is why a group of students from the Massachusetts Institute of Technology installed 10,000 light bulbs made form water in Philippines. This light bulb is composed of nothing more than one-liter plastic bottle, water, and bleach. The installation process is easy and can be installed in less than an hour. They have never needed to be replaced. They are maintenance free. To turn them off on the day time, they can be covered by a solid bucket. The light bulb lasts for five years, and is equivalent to a 60-watt bulb. The principal inventor was the mechanic Mr. Alfredo Moser and now the solar bottle bulb is illuminating poor settlements across the Philippines.

Figure 1: Water light bulbs installed in Philippines houses

This new creation gives us an idea of the power of water. Water can be used for everything and now is used to replace electric current. This water bulb works simply because the water diffracts the light, letting it spread throughout the house instead of focusing on one point and the bleach function is to keeps the water clear and microbe free. If this new invention reduces the consumption of normal light bulbs what happened if we try to reduce the overall consumption of electricity? Is a new alternative an is possible with some other experimentations, we want to grow and to invent technology but sometimes the simplicity and the natural resources like water give us more energetic and viable possibilities to create the new future. Is life without electric current possible? We don’t know but if we continue with experimentations like this we can create a different life style and a better future free of technology dependence.

References:

Reach Michael J. Coren, The World’s Cheapest Light bulb Is Made Of Just a Plastic Bottle. November 10, 2011.

Water Light Bulbs. Sustainable Times. October 8, 2008, November 10, 2011.

Additional resources:

http://www.boreme.com/posting.php?id=28861

2011-11-19T13:15:00.001-08:00

Applying physics to my everyday life: Human eye and corrective lens

Verónica Marie Cruz González

In the course FISI 3172 we have studied many different topics, but there was one that caught my attention. I could apply this topic to my life and I could finally understand how things work using physics. The topic I am talking about is Lenses and Optical Instruments. I’ve used eyeglasses since I was six months old because I have multiple eye defects. I never understood the prescription or which types of lenses I use, but now that we have studied this topic in class I can understand a little better how my prescription and glasses work.

The development of optical devices using lenses dates to the sixteenth and seventeenth centuries, although the earliest record of eyeglasses dates from the late thirteenth century. To be a little more specific, history records state that the first spectacles were made between 1268 and 1289.[1] Around 1284 in Italy, Salvino D'Armate is credited with inventing the first wearable eye glasses.[2]

There are two types of lenses; converging and diverging lenses. The converging lens is thicker in the center than in the edges and makes parallel rays converge to a point. On the other hand, the diverging lens is thinner in the center than at the edges and makes parallel light diverge. These lenses are used for many purposes but are very useful as corrective lenses for humans with eye defects.

Some of the eye defects discussed in class were; myopia, hyperopia, presbyopia, and astigmatism. Myopia, also known as nearsightedness, is when the eye can focus only on nearby objects. It is usually caused by an eyeball that is too long or that the curvature of the cornea is too great. In either case, the images of distant objects are focused in front of the retina (Figure 1 a.). The lens used to correct this defect is a divergent lens because it allows the rays to be focused at the retina (Figure 1 b.).

Figure 1: Nearsighted eye (a) Image is focused in front of the retina; (b) image is located on the retina with the use of a divergent lens

Hyperopia, also known as farsightedness, is when the eye cannot focus on nearby objects because the near point is greater than the “normal” (25 cm). It is usually caused by an eyeball that is too short or by a cornea that is not sufficiently cureved (Figure 2 a.). The lens used to correct this defect is a converging lens. Presbyopia is similar to farsightedness. It refers to the lessening ability of the eye to accommodate as a person ages, and the near point mores out. It is also corrected by a converging lens (for older people, bifocals are used.

Figure 2: Farsighted eye (a) Image is focused behind the retina; (b) image is located on the retina with the use of a convergent lens

Finally we have astigmatism which is usually caused by an out-of round- cornea or lens so that the objects are focused as short lines, which blurs the image. An astigmatic eye may focus on rays in one plane. Astigmatism is corrected with the use of a compensating cylindrical lens. Lenses for eyes that are nearsighted or farsighted as well as astigmatic are ground with superimposed spherical and cylindrical surfaces, so that the radius of curvature of the correcting lens is different in different planes.

Like I mentioned before, my eyes have multiple defects. These are; myopia, hyperopia, presbyopia, astigmatism, strabismus, and nystagmus. As you can see, I have all the defects discussed in class. But, how can one person be near and farsighted at the same time? Easy, I am nearsighted on the right side and farsighted on the left side. I always got these confused and never knew which one was which, but with the description in class and the book I was able to determine this. So with this we can conclude that I use a divergent lens on the right side and a convergent lens on the left side with superimposed spherical or cylindrical surfaces on each because I also have astigmatism.

Now, when I read my prescription I know what things mean. The plus sign (+) is for my left side because that is the convergent lens that corrects my hyperopia. The minus sign (-) is for my right side because that corrects my myopia. Even though this topic was only one section on the book, I now understand how to read my prescription and what types of lenses correct each defect.

[1] What man devised that he might see; Drewry R.D. Accessed on November 12, 2011.

[2] The History of Eye Glasses or Spectacles; Bellis, B. Accessed on November 12, 2011

Other Resources: Giancoli D. (2008); Physics for Scientists & Engineers Fourth Edition p. 882-884

2011-11-19T12:57:00.001-08:00

Logical Meaning through Complex Reasoning

César A. Rivera Collazo

What if? This question had been the reason for humanity to break the schemes and let creativity flow. This question had also been the responsible for many discoveries and improvements. Many people often ask themselves this question when they are up to something or when they are learning something. Students can be identified with this last one. During the semester we had learned how electrons and protons behaves in other words how electricity behaves and also how electricity and magnetisms relates with each other. Here is where the question comes from. What if? As a student I asked myself this question in order to understand and analyze what I have learned. Then creativity and ideas began to appear. When I was studying the topic about how current can be produced by magnetic field I asked myself, “If we know that current can be created from a magnetic field (change in magnetic field or change in area or change in the angle between both), What if we can power spaceships with magnetic field?”

This idea sound a little extreme and illogical but if we analyze how current is created from a magnetic field it would not sound that extreme at it appears. In order to create a current from a magnetic field we know that we need a loop of wire and a magnet. The current then will be induced on the wire by the change in magnetic flux. The magnetic flux is ∅_B=BAcos(θ) (B=magnetic field, A=area) so the only way to change the flux is to change the magnetic field, the area of the loop(s) of wire, the angle between them or simply all of them at the same time. With this in mind the idea of creating current from a magnetic field could sound reasonable.

The only question is: how the current will be transported to the spaceship? The current will not be transported to the spaceship it will be created in a recharge station on the orbit of the earth. We know that magnetic field can create and induce current. So what if we install a large magnets somewhere on earth and a recharge station somewhere on the earth orbit so the magnetic field could direct this field to the recharge station where a large wire with many loops will be nourished from this magnetic field. Now there are two problems one concerning the way magnetic field will be created on earth and the other regarding the way we will create a change in flux so an induce current would be created on the loop of wire at the recharge station.

To answer the first problem we need to know that magnetic field can be produced by a change in electric field (change in charge) in other words by a current. This current can come from a power plant or if we what to keep things clean we can produce this current from renewable energy (solar, wind, geothermal, etc). We also know that if the recharge station will be orbiting earth we need to install those large magnets on strategic areas around the world.

With this in mind we can answer the second problem, the way we will create a change in flux. In order to do that we know that we have to change the magnetic field, the area of the loop of wire or the angle between them. If the recharge station will be orbiting the earth the angle between them will be changing. Also we can manipulate the magnitude of the magnetic field by changing the current.

This idea of powering a spaceship with a magnet can be seen illogical for many, or can be seen as something taken from a Scifi movie. As a recall is only an idea and every idea has its restrictions at first when they are analyzed scientifically. We have to realize also that discoveries and improvements were born from ideas and is the work of engineers, scientist, physicist, etc to analyze the idea. They are the ones that are able to find a logical meaning by complex reasoning.

2011-11-11T20:00:00.000-08:00

Convert an AC voltage into a nearly constant DC voltage

Reimanuel Cruz Santiago

Often we use AC voltage to use electronic devices that need to function a nearly constant DC voltage. So, we want to convert an AC voltage into a nearly constant DC voltage to be used as a power supply for electronic circuits.

As studied in FISI3172 the AC voltage is sinusoidal but we need to convert it into a nearly constant like DC voltage so, we need to redesign a new circuit that can give me an a control of the voltage to convert it nearly constant. One option is to add in the circuit a diode, the diode is a very important device that has two terminals, the anode and the cathode the voltage across the diode is referenced positive at the anode and negative at the cathode. Similarly, the diode current is referenced positive from the anode to cathode. The characteristic of the Diode is if the voltage applied to the diode is positive, relative a large amounts of current flow for small voltages named this condition forward bias but for the other hand, for moderate negative values of voltage the current that pass for the diode is very small or cero called this condition revers-bias region. This property is very useful for example in automobile, diodes allow current from the alternator to charge the battery when engine is running but when engine stops, the diodes prevent the battery from discharging through the alternator. The diodes consist of a junction between two types of semiconducting materials with one side of the junction with impurities create n-type material in wish large numbers of electrons move freely and in the other side of the junction different impurities are employed to create a positively charged particles known as holes. If a voltage is applied with positive polarity on the n-side the barrier is enchanced and the charge carriers cannot cross the junction. On the other hand, if a voltage is applied with positive polarity on the p-side the barrier is reduced and large currents cross the junction.

Figure 1 Example of a Diode

To rectifier the circuit for charging a battery we can use a half-wave rectifier that when we connect to a source voltage if the voltage is positive, the diode is in the forward-bias region and when the voltage is negative the diode is in reverse biased and no current flow.

Figure 2 Example of a half-wave rectifier

Finally, a circuit that can be used to convert an AC voltage into a nearl constat DC voltage to be used as a power supply for electronic circuits is the Half-wave rectifier but with a capacitor. It function in the form that when the AC source reaches a positive peak, the capacitor is charged to the peak voltage and when the source voltage drops below the voltage stored on the capacitor, the diode is reverse biased and no current flow through the diode and the capacitor continues to supply current to the load, slowly discharging until the next positive peak of the ac input. As show in the Figure 3, current flows through the diode in pulses that recharge the capacitor.

Figure 3 Half-wave rectifiers with capacitor

Reference:

Electrical Engineering Principles and application 5th Hamley

2011-05-08T12:38:00.000-07:00

What The Universes Behold

Catalina M Ramirez Nazario

The universe we have learned about since we were little in school is very limited. It expands to horizons and immensities that we might have never imagines. Recently the thought has been present that, what if it is not just one universe… What if there is a multiverse! A lot of people haven’t even heard of concepts of black matter, black energy or about a false vacuum, which are concepts that are needed to understand the different theories and thoughts on parallel worlds and multiverses. This is a reason that may lead people to think that they are not well prepared or not capable enough to learn about the new thrills and discoveries of the Physics community. On the book Parallel Worlds, Michio Kaku takes readers by the hand into a tour of several theories, history and physics concepts that will make the reader be able to grasp an understanding of the out coming theories on the multiverse.

The book divides all the information into three major categories: the universe, the multiverse and escaping into hyperspace. In the first part, Kaku explains to readers about theories on how the universe was created, like the big bang, things that can make up the universe, new discoveries and also specifies the phases of the universe throughout its creation up to now. In the second part of the book we go into depth about the concept of a multiverse and all its meaning. This is a good transition because we are aware of what makes up and important concepts of our universe in specific, so we can truly appreciate and understand a bigger picture where there are more universes besides the one we live in. Here, Kaku introduces the concepts of super symmetry, time traveling, String Theory, M-Theory, among other concepts. In the third and last division of the book, Kaku discusses and escape to hyperspace. This consists of utilizing the concepts discussed earlier in the book which say that in a distant future our universe might end to be as we know it, and so, a future generation of society will have to device a way of surviving, and Kaku discusses the possibilities of using parallel universes as the solution.

The concepts in this book may not be the easiest to understand for someone with a minimum background in Physics, but the way that Kaku lays it out and explains the concepts is easier to grasp. He makes it simple because he explains basic concepts that make it easier to understand the main concept that he wants to make accessible to people. Even if you do not have an immense knowledge in Physics, you will be able to understand what Kaku wants us to learn through his books. This is a book that I would recommend for anyone who has a striving curiosity to expand their universe to a possibility of many universes After you have read it, you will be aware of a world of theoretical physics that will stimulate your curiosity, knowledge and imagination to the fullest extent.

Reference:

Kaku, Michio. Parallel Worlds: A Journey Through Creation, Higher Dimensions, and the Future of the Cosmos. New York: Anchor Books, 2006. Print.

2011-05-08T12:34:00.000-07:00

Transformers: From dream to reality?

Catalina M Ramirez Nazario

The generation that is cursing the university right now, has possibly grown with the image of cars and planes transform into alien robots and fighting to protect the human race. The transformers TV series, had most kids I know go crazy with the changes and the fights; but what is it that keeps this series alive? Even when you grow up, you still have that excitement and thrill when you see Transformers. Now, the real question is: how possible is it really to have transformers that resemble the one in the series and the movies? It is possible! A transformer in the series is an alien robot that resembles humans, but can change its shape from a car into this giant robot. If we were to turn this into a more realistic term of calling a robot a “transformer, then we could say that it is a robot that can change its shape to perform different tasks.

In actuality, building a transformer would not be impossible, but it would be highly improbable. We first have to define that there are three factors to consider as basics to the possibility of building a transformer robot like in the movies: size, energy and biped walking. We will first start of by explaining the size factor. Making a robot just as big as the ones we see in the movie is one of the challenges of design, but it is also a design to their wallets. Constructing a plan just for them is not a bad idea, they just need more men to execute and a little more of planification. Another aspect to be considered is how to provide energy to such a big object. There are many different ways to obtain energy: coal, gas, wind, tidal, etc. This all need to be considered thinking specifically which can produce enough energy for a 16 feet or 28 feet transformer robot? A good option to answer this question is to utilize hydraulic energy. This source of energy can be powerful enough for a robot of this magnitude, but there are several complications to implementing the systems such as tubes and pumps that will move the water throughout the robot. One very big complication is that the hydraulic systems will have to be implemented alongside the electrical wiring and pieces, without having the water damage them, even when the robot transforms and moves all of its parts to adapt to its shapes. This is not a problem for the movie characters because they have their own alien power source that gives them “life” and energy; which is called the cube. Another fact to consider is how to make a robot walk like a biped for a prolonged period of time. Experts in engineering and physics have been trying to work out this problem, with several prototypes; but the farthest they have gone has been Honda with a robot called ASIMO. This is a robot that walks like a biped, but his approximate height is 4.3 feet and his walking speed is 2.7km/hr and can run up to a speed of 6 km/hr. This is the farthest technology has gone in creating a biped robot, and it can only function for a time of 40 minutes to 1 hour. If we compare this to the size of a Transformer, we see that our actual technology is far from making this a possibility in a near future.

Figure 1: Honda’s ASIMO robot, walking down the stairs.

Although making a Transformer of the magnitude of those in the movies and the series is, at the present time, very difficult; there are several robots in science which are designed to transform to perform several functions or to adapt to their surroundings. These types of robots are divided into three main areas: self-configuring robot, chain robots, and lattice robots. Describing a self-configuring robot, we see that the robot is made up of a lot of small modules that move together to form a robot that adapts to different surroundings, but their usually only program to be good at doing specific tasks. A good example for this type of robot is the concept used for the Mars Rovers. Chain robots are a series of modules or robots which are joined together; they look mostly like a spider or a snake. An example of this type of robot is NASA’s Snakebot.

Figure 2: NASA’s Snakebot

Now, for the last classification for robots, we have the Lattice robots. This type is composed of a lot of small robots that have their own way of functioning, but combine to work as a bigger robot. An example of this is more of a Terminator T-1000 or a bank of fish uniting to form a big arrow in the Nemo movie; it is not so much seen as a Transformer like in the movie, but it does fulfill the purpose of the transformer.

Transformers are a child’s dream for a lot of people. While scientists have contemplated the different ways to make Transformer, it is not viable or it does not have a greater reason to spend the kind of money it needs to be done. Transforming robots exist already and are definitely possible! It is up to tomorrow’s physicists and engineers to turn some kids dream into a reality.

References:

Wilson, Tracy V. How Real Transformers Work. How Stuff Works; A Discovery Company. Internet. http://science.howstuffworks.com/real-transformer2.htm

HSU, Jeremy. NASA’s Shape-Shifting Robot Is “Real” Transformer. LiveScience. June 25, 2009. Internet. http://www.foxnews.com/story/0,2933,529059,00.html

2011-05-08T12:22:00.000-07:00

Claytronics: Programmable Matter

Omar A. De La Rosa Oliveras

Imagine holding your common portable phone which fits perfectly into the palm of your hand, and being able to transform it at will, within seconds, into a fully functional 20 inch portable computer, or turn your car into a motorcycle at will. Seems highly improbable right? Well, in theory, all this and more will be possible with the development and research of a new technology known as programmable matter. The main Idea is based on creating individual nanometer-scale building units which can be arranged and rearranged at one’s will.

These building units would actually be tiny computers, or micro robots, called Claytronic atoms or “catoms” which will be able to interact with one another. They will act sort of like atoms in the sense that they will be the basic building units of the object which will be formed from them. The position arrangement of these catoms will be controlled by programming, in theory, making it possible for the object composed from them to take any shape desired. Catoms will move in three dimensions in relation to other catoms, adhere to other catoms to maintain a 3D shape, emit variable color and intensity of light, communicate with other catoms in an ensemble, and compute state information with possible assistance from other catoms in the ensemble. The current state of this technology is a bit bulky compared to the final vision of the initial concept.

The current catom is a 44 millimeter diameter cylinder equipped with 24 electromagnets arranged in a pair of stacked rings. These electromagnets are the ones which make possible the interaction between the catoms. In the current design, these can only move in two dimensions relative to each other. To move, a pair of catoms must first be in contact with another pair. Then, they must appropriately energize the next set of magnets along each of their circumferences. These current models can beat the horizontal force due to friction while in movement with no problem, but downscaling will result in less force having to be applied by each catom to lift its weight and that of the others around it within an ensemble. A future model of less complexity is being developed to lower manufacturing cost and make it easier for mass production. These new models will only have the essentials for working within the ensemble which means they must work cooperatively with others in the ensemble to move, communicate, and obtain power. Today, extensive research and experiments with claytronics are being conducted at Carnegie Mellon University in Pittsburgh, Pennsylvania by a team of researchers. Reseachers believe this technology will be on its final stages within the next four decades.

Some current ideas for uses of programmable matter are for being able to display and reproduce moving three-dimensional scenes or images like the one seen in the picture above and for aircrafts to be able to change the shape and profile of their wings according to the different flight conditions. The phone and the car examples I gave at the beginning of the article may be ideas a bit too complex for the time being considering they consist of many complex internal mechanisms, but as this technology is being developed we will be getting closer and closer to making these ideas into possibilities.

Zakin, Mitchell. “Programmable Matter - The Next Revolution in Materials.” Military Technology, 32.5 (2008): 98-100. Academic Search Complete. EBSCO. Web. 28 Apr. 2011.

Goldstein, Seth. Campbell, Jason. Mowry, Todd. “Programmable Matter” Invisible Computing, June(2005):99-101.Web.27 Apr. 2011.

Flaherty, Joseph. "Claytronics – Programmable Matter." Replicator. N.p., 26 July 2009. Web. 27 Apr. 2011.

2011-05-08T12:10:00.000-07:00

Maglev trains revolutionizing 21st transportation

Yrret Marie Maldonado

Can you imagine traveling in a train that is suspended in a cushion of air and that can reach speeds that are up to twice as fast as those of a traditional engine powered train? Well thanks to the principles of electromagnetism, such a train exists and is called the Maglev train, which names mean magnetic levitation that refers to the ability of this train to suspend over a guideway using the basic principles of magnets. The powerful and innovative use of magnets and electromagnetic physics knowledge enables the Maglev train to become a high speed train, capable of revolutionizing transportation in the 21st century.

The basic physic principle behind the Maglev train is electromagnetism which is considered the branch of physics that deals with electricity and magnetism and the interaction between them and it was first discovered in the 19th century. Electromagnetism which is defines as the force that causes the interaction between electrically charges particles, and the areas in which such interaction occurs is called electromagnetic fields. There are two types of electromagnetic fields: electric field and magnetic fields, however, they are both manifestation of different aspect of electromagnetism and therefore are intrinsically related. In the way, that a changing electric field generates a magnetic field; conversely a changing magnetic fields generates an electric field. This effect is called electromagnetic induction. Also, Electric fields are the cause by electric potential and electric current and magnetic fields are the cause of the force associated with magnets. This knowledge of one of the most fundamental physical forces at work, the electromagnetic force gives way to the use of electromagnets like the ones that can be found in Maglev trains.

The underlying principle behind the working of the electromagnet is the use of electromagnetic induction. The basic idea is to create a magnet by running electric current through a conductor medium (like a wire), creating a magnetic field. Like regular or “permanent” magnets, the electromagnet attracts things made of iron or steel and fallows the fundamental law of all magnets: Opposite attracts and likes repel. The only difference is that electromagnets are temporary; they will exist only if electric current is flowing. The most conventional way to generate high intensity electromagnets is to wind a core substance, usually a ferromagnetic material like iron, nickel or cobalt with many coils of wire. Once this is done, electric current is passed through the magnets, which induces a magnetic field in the ferromagnetic core and is the basis of operation for marvel trains and electrical generators, induction motors, and transformers.

The concept of electromagnetism is used in high speed maglev trains. They use power full electromagnetic force to provide both magnetic levitation of the train and propulsion. The Maglev Train system consists of tree important components: a large electric power source, metal coils coating the guideway (or track) and a large guidance magnet attached to the underside of the train. The electromagnets which are fixed in the tracks magnetically levitate the train with no support other than magnetic fields and also helps move the train by magnetic force. This is done because the magnetized coil running along the guideway repels the large magnets on the train's undercarriage, allowing the train to levitate between 1 to 10 cm above the guideway. Once the train is levitated, power is supplied to the coils within the guideway walls to create a unique system of magnetic fields that pull and push the train along the guideway. The electric current supplied to the coils in the guideway walls is constantly alternating to change the polarity of the magnetized coils. This change in polarity causes the magnetic field in front of the train to pull the vehicle forward, while the magnetic field behind the train adds more forward thrust. The magnetic pressure is used to neutralize the forces and effect on gravity.

There are two types of Maglev trains: the German engineered electrodynamics suspension (EMS) and the Japanese engineered electromagnetic suspension (EDS), however both methods are based on the same concept, but differ in the approach as to what type of magnetic elevation used. As the EDS uses the repulsive force between the magnets, in the guideway and beneath the vehicle, makes the train levitate and move. On the other hand, the (EMS) uses the attractive force of magnets, in the guideway and beneath the vehicle, makes the train move. The EMS is faster than the EDS, because EDS train must roll on rubber wheels until they reach a lift-off speed of about 100km/h which causes resistance. However having these wheels is an advantage during a power outage, it allows the train can come to a smooth and safe stop. This fact makes the EDS safer, but also more expensive.

What makes the Maglev train such and innovation and revolutionary train it’s precisely the benefits this train offers in comparison to its more traditional counterparts. Being one of the biggest advantages that the Maglev train system does not use Fossil fuels like a traditional train engine, but instead is totally based on magnetism as the magnetic field created by the electrified coils in the guideway walls and the track combined to propel the train. Therefore, being more environmental friendly and reducing the dependence on fossil fuel. More so, the noise pollution is reduced to a significant level and air pollution is virtually absent. Also, the fact that Maglev train is able to levitate on a cushion of air has the effect of eliminating the negative effect of frictional force, this in combination with is aerodynamic design, increases the trains speed. The train can reach unprecedented ground transportation speeds of more than 310 mph, being twice as fast as the Amtrak’s fasts commuter train. Therefore, such a revolutionary train is a faster alternative to heavy air traffic when traveling. This and many other facts of the maglev train make this new form of terrestrial transportation a revolutionize 21st century transportation.

References:

http://science.howstuffworks.com/transport/engines-equipment/maglev-train1.htm

http://www.essortment.com/maglev-trains-work-40054.html

http://ninpope-physics.comuv.com/maglev/howitworks.php

http://www.buzzle.com/articles/maglev-trains-how-do-they-work.html

http://www.brighthub.com/engineering/electrical/articles/72138.aspx?p=2

http://science.howstuffworks.com/electromagnet.htm

http://www.brighthub.com/engineering/electrical/articles/62105.aspx#ixzz1L0tHLbGE

2011-05-08T11:42:00.000-07:00

Another Day, Another Glimpse at Air

Arnaldo Cruz Betancourt

The other day, a thought came to my head. This thought, for the level of understanding that I had at that time, seemed to have no answer. But now the thought have been answered and without further ado that was: “If we know that friction is present when two objects rub each other and friction transforms into heat energy. Then, does air friction transforms into heat energy?”

Friction is defined as a force that resists the relative motion or tendency to such motion of two bodies or substances in contact. This opposing force, in theory, “creates” heat no matter what two surfaces are in contact and consequently air friction does transform in heat energy. For example, have you ever try to put your hand outside of a moving car? At the instant you put the hand outside you feel a force pushing your hand to the back of the car and between that force and your hand exists friction, friction between the hand and the air that rushes by. When the hand is outside, you feel the hand is getting colder because of the temperature of the wind but you get your hand inside the vehicle what you feel is this rare feeling of the coldness of the air and at the same time the heat of the friction that this force produced. Remembering the law of conservation of energy that states that energy is neither created nor destroyed it can only be transformed from one state to another (from kinetic energy to heat energy).

Another more convincing example is, have you ever wonder why an airplane can’t depart if the outside conditions are icy and the temperature is cold? Well the answer is very simple, it is because the turbines of the airplane are frozen and the runway conditions aren’t appropriate to the plane to depart (icy runway). But what if we add an additive to the turbines for them to de-froze and add another additive to the runway to eliminate the ice in it, then the plane can depart. Getting back to the point, when the airplane is flying at a high altitude, the outside air temperature is colder than the temperature at the airport just mentioned and we can’t simply add an additive to the plane when the plane is airborne. Then, why the plane turbines don’t freeze? This is attributed to the force of friction present between the fluid of the air and the solid wing. Although the outside air is cold, the heat transformed from the force of friction counteracts the freezing component of air making the plane and the wings to work on proper work conditions in which the air temperature is offset by the heat caused by the friction. For which this quote can summarize the two examples presented: “A regular commercial airplane, after landing, will feel cool to the touch. But the Concorde jet, which flies at twice the speed of sound, will feel hotter than boiling water.”

In light of these examples, we can conclude that friction is a force in which at a result enables different types of energy, for instance as mentioned before, heat energy. The nature of friction is the one responsible that an airplane can work properly, the movement of a car and even the less expected, how humans move. For whichever the question is, the answer is there just for the human being to discover. Sometimes complicated, sometimes simple the answer may be but with the help of the powerful tool of physics, that has the ability to explain everyday phenomenons, by simple, clear explanations and mathematical equations we can explain such phenomenon.

References

http://www.parentcompany.com/creation_explanation/cx2b.htm

http://www.answers.com/topic/friction

http://www.scienceclarified.com/A-Al/Aerodynamics.html

http://www.scienceclarified.com/A-Al/Aerodynamics.html#ixzz1Ky13nFzU

http://www.allstar.fiu.edu/aero/fltmidfly.htm

Giancoli, Douglas C. Physics for Scientists & Engineers with Modern Physics. 4th ed. Vol. 1. Upper Saddle River, N.J: Prentice Hall, 2009. Print.

2011-05-08T11:33:00.000-07:00

This isn’t Rocket Science

Anibal X Diaz Ortiz

My dream has always being to work in a career field where the aspect of space and the universe were involved. This has led me to research a lot of companies and the company that supersedes the rest to me is the NASA. I gained interest in this area as a result that I would always hear the famous irritating phrase, “its not rocket science,” to mock me for the supposed easy task I was performing. So if this phrase is a synonym to one of the most rigorous disciplines, then I knew I would dedicate myself to one day become a rocket scientist.

Rockets are not as common as airplanes or helicopters, but they indeed fly. But the question is how does this occur? “The simple answer is that rockets fly by using Newton’s third law, for every action there is an equal and opposite reaction.” So in layman’s term the thrust the rocket expels, pushes the rocket upward to exit the atmosphere. The physics used to calculate the acceleration needed to depart is the conservation of momentum, “That is, for a given system, in our case the rocket-gas system, the total momentum will remain constant even if individual components move around. So if some component of the system (the gas) moves in one direction with a given momentum, some other object (the rocket) will have to move such that the two momentums exactly cancel each other out.” So if I heard the phrase “its not rocket science” so much, what was the deal with understanding this, as the equation needed to figure out the momentum is P=MV, where p equals momentum, m equals mass, and v equals velocity. Even though this equation is certainly true, its too simple to solve a complex problem, such as finding the momentum of this system, as thrust also needs to be incorporated, making it complex. And it becomes complex, because “you now have two masses to deal with, and two momentums to deal with. However, keep in mind that the total momentum of the system remains unchanged. So if we call the change in the velocity of the rocket dV, the mass of the gas emitted dM, and the velocity of the gas emitted relative to a stationary observer U, then the situation becomes Pf=U*dM+(M-dM)(V+dV), since the momentum of the system is equal to the momentum of the gas plus the new momentum of the rocket.” With this I really started to appreciate the work and time dedicated to understand the principles and concepts needed to realize such million dollar experiments.

Momentum isn’t the only physics concept applied when dealing with these complex systems; specific impulse, thermodynamics, and many others are also found. But specific impulse, “the change in momentum per unit mass for rocket fuels, or rather how much more push accumulates as you use that fuel” also needs to be calculated as it’s found by dividing the total impulse by the weight. This is crucial, because according to the NASA, “First, its a quick way to determine the thrust of a rocket. Second, it is an indication of engine efficiency. Third, it simplifies mathematical analysis of rocket thermodynamics. Fourth, its an easy way to "size" an engine during preliminary analysis.” In conclusion both momentum and specific impulse are probably the most important themes in rocket science, because the goal of launching a shuttle is to move the rocket as fast as possible, allowing maximization in cargo capacity, which is done none other than making the thrust faster and stronger.

References:

Benson, Tom. "Specific Impulse." NASA.com NASA Glenn Research Center, 11 July 2008. Web. 29 Apr. 2011. .

"The Physics of Rockets." The Physics Behind The Rocket. Http://www.uaf.edu/. Web. 30 Apr. 2011. .

"What Is Specific Impulse?" Welcome to QRG. Www.qrg.northwestern.edu. Web. 29 Apr. 2011. .

2011-05-08T11:27:00.000-07:00

The Physics of Bungee Jumping

Jesmarie Hernández Cruz

Modern bungee jumping has been an extreme activity for those in search of an adrenaline rush and excitement all around the world. This sport consists on jumping off any sort of tall structure, such as bridges or buildings, while being connected to a large elastic cord that falls vertically downward until the elastic bungee cord comes to decent to a stop, before pulling back and afterwards oscillating up and down until the energy is dissipated. The rebounds or oscillations are what give the person the thrill of the sport. Nowadays, bungee jumping has become a popular trend for many amateur jumpers, but what many enthusiasts of this sport don’t understand is the physics behind bungee jumping, and how important it is for the jumper’s safety.

Hooke’s Law of Elasticity states that the force of an elastic object uses to reinstate itself to an original length is relative to, but in the opposite direction, of the length the spring is stretched. Mathematically this law is expressed as F=-kx, where F represents the quantity of force necessary to restore elastic material to its position, k is the spring constant, x is the distance between the stretched cord to the initial position of equilibrium, and the negative sign means opposite direction and not negative value. When this law is applied to bungee jumping it basically tells us how much tension a spring can endure and the maximum length it will reach.

It must be taken into accounts different aspects; such as potential energy, kinetic energy, elastic energy, the different forces involved (like gravity, and weight of the jumper), distance to fall, etcetera when bungee jumping is involved. Before the jump, the person is at a specific height, in which there is a certain amount of potential energy (m*g*h). Once the person jumps he enters the free falling, in which gravity is the only force acting on the motion of the body, and this is where the energy begins converting into kinetic energy (0.5*m*v2). After the free falling has occurred in a matter of seconds, the jumper now has fallen to a specific length. In this moment which the ropes starts to elongate, the kinetic energy starts to transform into elastic energy (0.5*k*x2), which is stored in the bungee cord. This elastic energy will first come from the gravitational potential energy. Both the elastic and kinetic energy will begin to grow until an equilibrium point is reached. It is then that the force of the bungee cord will begin to outbalance the weight of the jumper, and now he will decelerate. Then the jumper will have fallen at the bottom extremity of the jump, which is the length plus the distance that the bungee cord has stretched to. Additionally the velocity at that moment is equal to zero. Afterwards oscillations will then begin, pulling the jumper up and down until all the energy has dissipated and the cord will return to its original shape.

The organizations or groups that conduct bungee jumping must take many decisions into account before providing others with this activity. For example: owning the right equipment, knowing the types and maximum lengths of the bungee cords for different falls, and it must also be taken into account the weight of the jumper (because cords do have a specific weight limit). These are all very important because they guarantee the safety of those who practice this sport, and also one way or another are indefinitely related to Physics. To conclude, Physics laws and principles helps us understand many aspects involved in the different activities that we conduct in our lives. For bungee jumping, modern physics explains and simplifies every detail involving how it occurs and why it behaves in the way it does, resulting in a much safer and more enjoyable sport for everyone participating.

References

Giancolo, Douglas C. Physics for Scientists & Engineers with Modern

Physics. 4th. Upper Saddle River, N.J: Prentice Hall, 2009. Print.

Taphorn, Amanda. "Bungee Jumping with Elastic Force." Physics247. N.p., n.d.

Web. 29 Apr 2011. .

2011-05-08T11:19:00.000-07:00

Sky Colors

Grecia P. Butler Pérez

Since, I was a little girl, I question myself, why the sky is blue? I pass a lot of time looking the sky and all the beautiful colors in it. It has an intense yellow and a shiny orange when the sun comes down and a baby blue and a dark blue when a sunny day is or the rain is coming. This situation was interesting for me and I decide to investigate to found an answer for my question. The important part is that the colors of the sky have a physical explanation. The sky is like a prism; it reflects colors.

The beauty of the sky is the result of the interaction between the sun light and the atmosphere. It’s necessary the damp and the particles of dust to have an impressive fest of colors in the sky. The most seen color is the blue. The presence of this color is like when a sun ray passes through a prism. When we have this situation, the prism refracts the sun ray in five colors: purple, blue, green, yellow and red. The color rays with less wave length are purple and blue. The other three rays have long wave length. The short wave length colors have more deviation. These two colors with more deviation collide with air particles and it trajectory changes, when this happen the two colors collide with another air particle. The collisions of the purple and the blue rays with the air particles make it travel all the sky and then reach our eyes. When the rays reach our eyes we see the blue color in the sky. This is a cyclic process; it is happening all the time. This energy diffusion process is called Rayleigh diffusion. The blue sky color is a result of the diffusion of the wave with short length

The color with less wave length is the purple color. If we analyze this situation, the sky is supposed to be purple. The sky isn’t blue for two reasons. The first one is, the sun rays have more blue than purple and the second one is the human eye is more sensible to blue light. For these two reasons the color of the sky is the blue. If the particles are big the Rayleigh diffusion doesn’t work. In this case the process needed is the Mie diffusion. For this diffusion the sky isn’t blue. When the clouds are too thick the sky turns gray. This is the situation in rainy days. When we see the sun coming down the sky turns orange and red. This situation is because the rays of light moves more and the colors with short wave length are capture in the particles. Only the red rays survive because it travels in rectilinear movement. If the earth haven’t had atmosphere the sun light would reach our eyes directly without diffusion and we would see the sky black. The astronauts watch this effect in space. With this effect they can see the planets, stars and the moon, because there is no atmosphere.

Now I understand the color and appearance of the sky, because it has a physics explanation. Isn’t a simple act of being blue, it is a relation between particles and light rays.

2011-05-08T08:52:00.000-07:00

Proton therapy

Alejandro N Torres Santos

Physics can be used in all aspects in our life, including saving lives. Proton therapy is an example of that. Was the american physic Robert Wilson the first person to talk about proton therapy in 1941, since then this program refined and expanded these techniques while treating 9,116 patients that suffer of cancer. The first treatments were made by particle accelerator made by physicians in Sweden. Its commonly know that we can cure cancer using radiation with x-rays, but we know that is a painful process with side effects that includes hair loss, radiation nausea and fatigue. Using proton therapy all the side effects are gone and patients can continue normally with their life after their treatment.

Cancer is a known disease that destroys tissue with uncontrolled growth. Society is trying to fight this disease that is killing 8 million people each year, so we have different types of treatments. Proton therapy is one of many treatments but people may not know about it. Tissues are made up of molecules with atoms. In the center of every atom is the nucleus and inside are orbiting negatively charged electrons. The protons pulls electrons out of their orbits. With their positive charge they attract the negatively charged electrons occurring the ionization that changes the characteristics of the atom and the character of the molecule within which the atom resides. In other words protons damage the DNA of cells, causing their death or interfering with their ability to reproduce. The cancerous cells have a high rate of division, their reduced ability to repair damaged DNA is particularly vulnerable to attack on their DNA, so by adjusting the energy of the protons during application of treatment the cell damage due to the proton beam is maximized in the specified cancerous area (tumor).

The important characteristic that defines proton therapy is that doesn’t damage other tissue closer to the tumor because other areas receive less radiation. Contrary to the conventional x-rays that results in most of their energy from a single conventional x-ray beam being deposited in normal tissues near the body's surface, as well as undesirable energy deposition beyond the tumor site. This undesirable pattern of energy placement can result in damage to healthy tissues close to the cancerous area. Standard x-ray therapy and proton beams work on the principle of selective cell destruction. The major advantage of proton treatment over conventional radiation is that the energy distribution of protons can be directed and deposited in tissue volumes designated by the physicians-in a three-dimensional pattern. Proton therapy is also best than surgery if the tumor is located in places were surgeries are risky like closer to the brain and other important organs. After the treatment patient experiences a better quality of life and feels nothing during the process. The minimized normal-tissue injury results fewer effects following treatment, such as nausea, vomiting or diarrhea. The problem with proton therapy is that needs a high cost machine which cost is approximately half a million dollar. Also is available only in nine centers in the worlds, making this treatment one of the most expensive and exclusives ones.

2011-05-08T08:26:00.000-07:00

Internal Energy of an Atom: Heat as Change of Internal Energy

Emmanuel J. Chamorro Rivera

Energy, the ability to do work, and the concept that keeps every particle in the universe moving, reacting; for us this concept is difficult to understand, but it can be calculated. Kinetic energy and potential energy are two basic types of energy that are particular to the system, but those two are derivatives of an even greater energy, the contact between electrons of an atom. In other words when we touch something, the electrons of the tip of our fingers have contact with the electrons of the object. That is precisely the source of sounds and transference of heat. If that is the case, then the atoms carry an internal energy which makes possible for them to do work, and exert forces to different directions. This means that this energy can be transferred and used, but even more important this energy can describe the elements and the components in matter.

The only thing that is missing is an equation, only a formula to calculate this energy; but it is not simple as it sounds. To find it, speed, acceleration, and position have to be known, which to find for an atom is extremely hard to find. Also Heisenberg’s uncertainty principle can explains that finding those for an electron is impossible at the same time, so the choice of using electrons to measure it also becomes complicated. Although there is another approach, for example, water vapor in a sealed refrigerator. We know that water then would eventually turn to liquid, or solid, so if viewed from a chemical point we know that the water vapor is releasing energy, which can be measured. Now must we ask what type of energy is it liberating. Is it only thermal? Well, yes, it is thermal, but also it can be seemed as internal energy. The state is a property of matter which atoms move a different speed. So the thermal energy can be seemed like a conversion from internal energy to thermal energy. Which thermodynamics help to resolve these problems as seen in:

∆E_int=Q=mC_s ∆T ,for changes of temperature in same phase

∆E_int=Q=n∆H,for changes of phases

m=mass

C_s=constant of specific heat

T=temperature

n=moles

H=entalpy associated to the change of phase

But what exactly does internal energy implies, well we can use the knowledge of chemistry to define the term of internal energy. Now let’s remember heating curves, when a compound is solid, it needs to absorb internal energy in order to change phases. Well this may mean that compounds that are gas at room temperature have more internal energy than an abject which is solid at room temperature. For example, we have one gram of ice in a closed system, if we heat it up and have the same amount of water vapor in the same closed system; the vapor exerts more force in terms of pressure than the solid. Ergo the internal energy is larger when a compound is in gaseous state. Now what may this imply? In chemistry there is a term to describe why does certain elements are in different phases, known as intermolecular forces. The larger the forces, stronger are the bonds between the atoms; the more likely the compound would be solid at certain temperature. Well this can give us a proportion to internal energy:

E_int∝(1/F_(inter ) ),F_inter=intermolecular forces

This proportion may seem easy at first, but the term of intermolecular forces is not yet defined as a number; it is defined as a theoretical term. Finding that number is the key to finding the internal energy of a compound in any time in a specific temperature, and from this then the composition can be known. To find the value of the forces, as well as the dimension, experiments have to be conducted for further analysis.

Internal energy is the fundamental energy of all particles, how it changes can be calculated, but the exact value is a mystery. Atoms contain this energy which allows them to make work. This energy is a property of matter itself. The understanding of this energy may drive us to understand more about atoms and how they react. Needless to say this energy is present at all times of our daily lives. Measuring it like another type of energy should be possible, even if now it seems improbable to do so. The proportions are theoretically easy to find, but the true values are far from being, found. With the adequate equipment and extensive knowledge of composition of matter, eventually should lead to the value of intermolecular forces, which is key to understanding the energy which exist in every atom in the universe: internal energy.

2011-05-08T07:50:00.000-07:00

Physics in the Dance

Marjorie Carrión Rodríguez

In the life the humans have different passions and interests. These interests may vary depending on the possible skills in each person. It is incredible that many of us do not realize that our whole world and everything we do is possible for many factors but one of them is very important. For example, the Chemical and others things but I believe the most important is Physics. We begin by defining, what is the physics? Physics is a natural science that studies the properties of space, time, matter and energy and their interactions. Now we know its meaning and we can think if any activity that we do every day and is very passionate have influence of physics. For my part one of the things I like very much is the dance. Since I have use of reason I dance and now I realize that not only we need ability to dance, there many factors that affect it and this factors not depend of me for example the science of physics.

Given that physics studies many aspects of the world, we know that some factors that affect the dance are the laws of gravity, momentum and energy. The same influence on the subtleties of balance, the techniques of leaps and pirouettes, and the impressive lifts and turns executed by the partners and body dimensions in the art of ballet. We begin by gravity which is very important if not the principal and it is responsible to keep the dancers in balance. The gravity effects depend of gravity center. The gravity center is the point where reflects all the forces applied to the body of the dancer. The forces are more than one. The weight combined with the movements and the force exerted by the surface of the floor to the dancer. At the same time the gravity influence the jumps and spins, controlling the speed to controlling the configuration of the body and rotational inertia, the generation of adequate forces on the ground to initiate movements, controlling the time and height of the jumps.

In the dance the kinetic energy is important to study the movement of the dancers. The dancers make work to do their movement. That movement can be done with coordination and perfection that also needs to develop a specific acceleration starting from rest and integrating the couple that is an additional source of force that combined with the gravity and soil.

Something that calls my attention was an engineer that use pieces of bricks and for physical process caused an explosion called The Physics of Dance. This engineer make possible that the pieces of bricks dance a beautiful song. For me the fact of know that the physics can do things that a lot of us thought are impossible to do is something incredible and surprising. Personally the dance is one of the things that make me happy and comfortable, I love the dance and today I understand that physics is very important in the developing dance.

2011-05-08T07:34:00.000-07:00

LIGHT PASSES THROUGH OPAQUE MATTER

Omar A Piazza Hernandez

It has long been believed that rays of light bend around objects and, of course, pass through them if they are clear, but new research has proven that when it comes to opaque surfaces, light can indeed pass through. Most people learned this in high school and assumed that that was the main difference between clear and opaque surfaces, but now that notion is starting to get heavy scrutiny.

When light passes through an opaque object, most of the energy usually bounces around the surface of the object or is scattered back to the source, while very few light particles actually make their way through. It is kind of like putting grains of rice through a strainer, where few grains make it to the other side and most of them get stuck in the strainer. Using special filters in a new experiment carried out in the Netherlands by two scientists named Ivo Vellekoop and Allard Mosk, most of the radiation actually passed through a layer of milk, illuminating the other side.

Scientists used cow’s milk for example because it had been thought that when light strikes an opaque substance like milk, it scatters around instead of penetrating it completely. In new studies, that has not been the case. The filters they used make the light particles behave differently, whereas in a normal, controlled scenario light would strike opaque matter in an orderly fashion, these new filters actually disorganize the ray of light and distribute it unevenly across the surface. The randomly distributed particles then propagate through the object at a higher rate than orderly rays, although some still bounce back to the source. This new technique, although very rarely seen in nature, questions the modern definition of opaque substances.

The experiment had been years in the making, but now these remarkable conclusions have been confirmed. Although further optical experiments are underway for theorists to find a catalyst for these studies, the base work is mostly done. Scientists believe that they could apply these new findings to technology. Whether it is sunglasses or paint primer, the immediate benefits of such every day applications is obvious. Imagine a greenhouse built with opaque panels, something like wood or concrete, but as you open the door you find plants growing in its seemingly dark interior.

I found this story interesting because it directly challenged my knowledge of light as I know it. In high school, “clear” meant “transparent”, which would allow light to easily penetrate it, and “opaque” meant “not transparent”, which obviously would have the opposite effect. I find it amazing that such a theory had not been developed before. I would also love to find out if there is one true opaque substance, which would be 100% impenetrable to light even under the toughest experiments. Such a material could really have its uses in technology, although none pop into my mind at the moment. Still, this news attracted my attention because of how simple it sound, yet how significant the discovery is.

2011-05-07T18:21:00.000-07:00

The Dead Sea Vs. Fresh Water

Daniel Maldonado Sanchez

Throughout my life, I always wondered why I floated much better in the beach than the pool. Since I always was fascinated with documentaries on bodies of water such as the Dead Sea and the Great Salt Lake, I decided that something in these bodies had something unique that allowed great buoyancy. Because of my interest in this question, I turned to the concept of buoyancy. Buoyancy is nothing other than “the tendency of a body to float or to rise when submerged in a fluid.” But in order for this to happen, the fluid has to exert an upward force on the body in order to maintain the body above the surface of the body.

From common sense, I knew that the salt had something to do with this phenomenon, but that was all I knew before I understood that physics principles apply in order for this to take place. The principle that significantly applies to this is Archimedes’ Principle, which states “if the weight of the water displaced is less than the weight of the object, the object will sink, otherwise the object will float, with the weight of the water displaced equal to the weight of the object.” So if the displaced water weighs less than an object that is trying to float, then it will sink. But if the displaced water is equal to the object trying to float, then the object will indeed float. This cleared many doubts in my mind, because when I spread my body as uniformly as possible, I tended to float evenly, compared to when I stood up in the water.

The salt that I knew that had something to do with this absolutely did, as “the Dead Sea has a density of 1.24 kg/L, making swimming difficult, but providing a relaxing floating experience.” And because “the density of fresh water is 1.0kg/L and that of a human body is of 950g/L, therefore an individual can float with ease over the water.” If we put the numbers into perspective, then one can conclude that if one has the capacity to float with not much trouble in fresh water of 1kg/L, then it will be way easier to float on denser saltier water of 1.24kg/L. I finally understood that the beach water was denser than the pool water from which I swam regularly, as a result of all the salts and minerals the beach has in its recipe.

Floating is summed up in a couple of concepts and principles; density, buoyancy, and the principle formed by Archimedes himself. Understanding these concepts and principles, will guide one into realizing that floating has many interesting physics principles applied, if one tries to question why one is floating in the first place. Once one floats, the upward pressure on the body on the water is equal to the weight of the fluid displaced by the object. Displace the weight of an object and the object floats, making the person enjoy his or her time in the body of water when trying to perform this motion.

References:

"Archimedes' Principle." Physics. Web. 28 Apr. 2011. .

"Buoyancy - Definition and More from the Free Merriam-Webster Dictionary." Dictionary and Thesaurus - Merriam-Webster Online. Web. 28 Apr. 2011. .

"Dead Sea." Wikipedia, the Free Encyclopedia. Web. 28 Apr. 2011. .

Hernandez, Antonio J. "LA FLOTACIÓN." Enseñanza / Metodología. I-natacion.com. Web. 28 Apr. 2011. .

2011-05-07T18:04:00.000-07:00

‘Potato Earth' Reveals Gravity's Uneven Pull

José J. Fontán Pagán

The shape of the Earth has historically been a point of debate among people since centuries ago. First it was flat, then round, but now scientists have uncovered that it might more closely resemble a potato (in terms of gravitational pull, at least). Scientists developed a graphic that shows how gravity affects both sides of the planet at any given time, and the results show a ‘potato’ planet that looks more like the well know tuber rather than an orange.

This new data will have big implications in terms of climate study as far as how they are approached. In light of this new info, we can explain how various natural disasters came to be, such as tornadoes, hurricanes, earthquakes, tsunamis, and even landslides. The satellite that captured the images is called Goce, a digital imaging satellite used by the European Union.

Theoretically, we can assume that the gravitational pull in France, for example, is stronger than that in America, although that hardly explains the gap in height between the two nations. It does go a long way at explaining natural phenomena in those areas with differentiating gravitational pull, and why some natural disasters, as I said before, happen in certain regions and not in others. These new images may one day save countless lives, and in fact, in the most recent images after the Japan earthquake we can actually see that the country moved at least three feet and the area’s gravitational force slightly fluctuated during the tremors before settling down once again.

Ten years ago, this finding might have all seemed like science fiction, but years of hard work and research finally uncovered the true shape of the earth, without the spherical atmosphere surrounding it. The discovery is hailed a result of the congregation of Europe’s best minds and efforts. Thanks to this new achievement, maybe we will revive some of the age old arguments of round versus square and replace them with round versus “slightly potato shaped”.

All jokes aside, I found this article mind boggling when I first saw it on BBC. When you actually see the picture, you can barely tell it is the planet Earth. It looks more like a slowly deflating basketball than a planet, but I guess this where technology has led to. There are colors on the images that depict blue for low gravitational pull and red for high gravitational pull, which makes me question why Americans are not generally taller than the French, since they get hit harder by gravity. I noticed that most of continental Europe is inside the high gravity zone, while most of the Pacific and the Americas are not. Both poles also get a high amount of gravity, although their effect probably is not witnessed as much as other, more densely populated areas. Still, it is a nice little footnote to have nearby next time somebody wants to boast about new discoveries, as surely someone would challenge the notion that the planet is a potato.

2011-05-07T17:44:00.000-07:00

SUPERCONDUCTORS

Josue A. Quinones Crespo

A team of Japanese physicists recently discovered a conductor to end all conductors: one that still works well even after 50 Kelvin. Superconductivity is an electrical resistance of exactly zero which occurs in certain materials below a characteristic temperature. Normally, superconductors are used to transport energy and usually they lose very little in the process, but most of the time they are copper based and extremely brittle after a certain heat threshold. Silver based superconductors are being used as well for their relative durability, but the cost of making them has made copper the current favorite, in spite of its obvious deficiencies.

The new superconductors are made from a fluorine enhanced iron arsenic material that can work at very high temperatures provided it is cooled constantly. They never burn out because the iron arsenic compound used to make the wire has an unequaled tolerance for low temperatures as well as high ones, sometimes exceeding tens of Kelvins. The capabilities of the powerful superconductors would make it last for hours on end pumping out high levels of electrical currents, something that the current ones cannot say. The materials used to manufacture this new type of superconductor are often cheaper than their silver and copper counterparts and offer the same type of production.

The only flaws that have been predicted with the iron arsenic superconductors are the amount of capital need to cool them down and the relative difficulty it takes to turn the compound into miles long strands of wire. These have generally been concerns regarding superconductors, but the benefits outweigh the flaws in various high electrical current applications. For example, MRI machines usually require massive amounts of electricity to operate for long periods of time. These new superconductors may be appealing to MRI machine manufacturers because it necessarily lowers the cost of materials and exceeds the shelf life of their current products. The experiment, led by scientist Hideo Hosono, looks at making superconductors more efficient in operation and more easily maintained, therefore making them widely available for heavy duty use.

I found this story entertaining because I thought superconductors were a technology that was abundantly used in our modern world. I have heard the word tossed around a few times before, so I instantly assumed it was a commonly used technology. I am glad to see some research being done to progress our knowledge of superconductors because I believe it has much more potential than our current batch of superconductors. It is sad to see that so much heavy duty equipment is still operating with obsolete technology when we are just steps away from creating the new generation of conductivity. It is similar to having the technology to build the world’s fastest computer, but then saying it is too expensive or to inefficient to maintain instead of figuring out a way to make it cheaper and more efficient. Hosoma not only basically did just that, he paved the way for mass production of these new superconductors and hopefully they will be in use sometime in the near future.

2011-05-07T15:58:00.000-07:00

Flying: The feat we thought impossible

Jan K. Huertas de la Cruz

The most beautiful thing of physics is that no matter how complex or simple things may look, the reason of their happening can always be explained with physics. That is why the field of physics is always around us, making cars run all by themselves, explaining why when you take a shower the water goes straight down towards you instead of just floating away, why when we throw a ball it has to stop at some time, to put it in the simplest most understandable way, physics is everywhere. But there is one thing that in older times was thought to be impossible, but in our era is one of the most important and safest ways to travel, flying.

The physics and engineering principles involved in making airplanes fly are very complex and hard to explain without using mathematics to understand it, but the idea to how airplanes fly can be explain in a nutshell. For any airplane to fly there must be four essential aerodynamic forces that must act on the plane, these are: lift, thrust, weight and drag. To better understand these forces we can draw a free body diagram to see how these act on the plane.

In this free body diagram A is the lift force, B is the thrust force, C is the weight force and last but not least D is the drag.

Now, if we want the airplane to fly straight, leveled and in a constant speed, the thrust force must be equal to the drag force and the lift force must be equal to the weight force. But everyone knows that first we need to take off the ground and then we need to land, so these equalities won’t match always.

In the aerodynamic forces the weight force is the simplest to understand, so let’s start there. Since all objects have mass, every mass have a weight, and this weight produces a downward force. The thrust force is an aerodynamic force that the plane must create in order to overcome the drag force (which I will explain later), this thrust force will make the plane go forward, it will make the airplane accelerate, and each airplane has a different method to produce thrust, some of these methods are propellers, jet engine and even rockets. Now, the drag force is the equivalent to the normal force in one dimensional motion, it just has some different aspects. The drag force is the force which resist the motion of an object that moves in a fluid (air and water are both fluids); to better understand it we can use a simple example. When someone sticks their arm outside the window of a moving car they must have noticed that the air pushes their hand in the opposite direction the car is moving, that is drag, the more mass and weight the airplane has the more drag it produces.

Lastly we have the lift force, unfortunately this is the trickiest and most debated force of the four dynamic forces. There are different explanations to how the lift force acts on the plane, but I will use the simplest one, the “Longest Path Explanation”. This theory states that the top surface of a wing is more curved than the lower part of the wing, and when air approaches the wing the air that goes over the wing and under the wing takes the same time to cross it, and since the top surface is curved it must travel more distance and in order for both winds to cross the wing at the same time the wind at the top moves faster than the wind at the bottom. Here is a little diagram to better explain it.

Now, since the air that goes over the wing moves faster this causes the pressure to decrease according to Bernoulli's equation, and since the lower wind goes slower this causes a more normal pressure. This difference in pressures makes the wing to move up, in other words the low pressure at the top of the wing acts as a vacuum, making the wing move upward.

These are the four essential aerodynamic forces that must act on the plane in order to fly. The physicists and engineers that have put a lot of work and time in the research of this extraordinary phenomenon are the reason for this achievement of our modern era. I hope that for our future our generation can develop better ideas that can amaze everyone’s eyes.

References:

• Giancoli, Douglas C. Physics for Scientists & Engineers with Modern Physics. 4th ed. Vol. 1. Upper Saddle River, N.J: Prentice Hall, 2009. Print.

• "Aeronautics - What Makes An Airplane Fly - Level 1." Aeronautics Learning Laboratory for Science Technology, and Research (ALLSTAR)Network. Web. 27 Apr. 2011

2011-05-05T19:05:00.000-07:00

Relativity: beyond the speed of light

Luis A . Muñoz Torres|

Here a while back I was talking with a colleague who is taking a physics course on relativity. Really struck me about many concepts of how matter in the aspect of movement and travel in the Earth versus that of outer space. Someday a human being can travel at high speed as light? What would happen if we achieve? Come to be so fast that we could visit other universes? The are many questions each person, scientific and engineering is done in this field of physics. Relativity is the gravitational attraction between masses observed is due to a curvature of space-time and therefore reflects the geometry of the forces rather than distance as is sometimes thought. In search of an answer the scientist Albert Einstein and relativity that as no information can travel faster than light, and therefore there can be no causal link between two events joined by a spatial interval. However, one of the cornerstones of the theory of Newtonian gravity, the principle of action at a distance, is that changes in the gravitational field produced will be transmitted instantaneously through space. The contradiction between the two theories is obvious, since assuming Newton's thesis would imply the possibility that an observer would be affected by the gravitational perturbations produced outside the cone of light. So the theory must be met in the physical laws must be enforced in all axes, the free inertial motion of a particle in a gravitational field is carried through geodesic paths, and that the principle of equivalence, the laws of special relativity apply locally for all inertial observers (which people can watch from any angle so that the Commission observed. The main principle that would make certain the principle of equivalence between an object and the observer says it is supposed that a system is in free fall and one that moves in a region of space-time without gravity are in a substantially similar physical state: in both cases the inertial systems. According to classical mechanics distinguish between bodies of inertial motion (at rest or moving at constant speed) or non-inertial motion bodies (those undergoing accelerated motion). Under Newton's second law, any acceleration was caused by the application of an external force. The relationship between force and acceleration are expressed by this formula:

m = F/a

But it is thought that gravitational effects are not created by any force, they find their cause in the curvature of space-time caused by the presence of matter. This shows that the transmitted light from distant objects never travels in a straight line but travel in a curve because of space-time that occurs in the vacuum of space outside the universe where light travels .

2011-05-05T18:53:00.000-07:00

The Theory of everything

Juan G Berrios Merced

The main thing about the field of Physics that captures my imagination is the search for a unified “General Theory of Everything”. The idea of a theory that held universally, that could be used to solve any problem in principle is fascinating, and makes one wonder if it is even possible.

There are the well-known and long established theories of general relativity and quantum mechanics, which despite very robustly explaining countless phenomena, cannot be said to hold universally, and are impossible to unify in order to shore up each other’s weak points, as it were. New theories have sprung up during the past decades which attempt to go beyond current paradigms framed around quantum mechanics and general relativity, such as string theory, and are having their tenets tested in the real world.

Indeed, in a large underground installation along the French-Swiss border, scientists are working with the largest particle accelerator man has ever made, the Large Hadron Collider, running experiments to finally settle whether there can truly exist a general theory of everything. One of the aims of these studies is to find the Higgs boson, an as of yet hypothetical particle that would go a long way in proving some of what String theory and particle physics as a whole espouse. I personally try to follow the results of their work as best I can, given my limited knowledge of particle physics.

The existence of a theory of everything has many detractors, who doubt the possibility of a theory that explains everything while maintaining full logical and mathematical consistency. Some claim that the very fact that nature is tied to infinity makes it impossible. Other claim than in attempting to explain absolutely everything, it would contradict itself (for instance, the same equation that proved something would also disprove it). However, there is no consensus in the scientific community that a theory of everything cannot exist, and that it should not be pursued. It is generally believed that further experimentation is the only way to know for certain, which is why experiments such as those done with the LHC are so essential.

These concepts are often too abstract for anyone without years upon years of formal training and study to even begin to comprehend, which is why most people simply assume it’s not important or interesting. I don’t claim to understand even a fraction of what it all means, but I am constantly compelled to try. The idea that one day we humans may have the ability to think about infinity without hitting an intellectual wall is quite fascinating to me, and the only way it will come about is through the eventual discovery of a unified General Theory of Everything. I personally believe it is only a matter of time before that happens. Physics, after all, is the study of everything. It would therefore be fitting that it could offer us a theory of everything.

2011-05-05T18:36:00.000-07:00

Newton: A key point in the study of Physics

Soleny González

The complexity of our universe is immeasurable and every phenomenon that occurs all around us and is being studied to find answers to why nature acts a certain way. One branch of science that focuses on this subject is Physics. Physics is a science that is responsible to study and explain phenomena, principles and reactions of all that is known as nature, from space to terrestrial. Thanks to great scientists and professionals who have devoted and dedicated his life to the study and development of this science is that today we have many answers to countless questions we ask when we look at every event that happens in the universe. We had the opportunity to know the progress of many scientists as was Aristotle, Einstein, Pascal, Archimedes, and others. If we try to name a few would be almost impossible because thanks to them all is that today we acquire everyday knowledge of science and mathematics but personally I want to emphasize through this article the work of Isaac Newton, for me is a personage of great importance since it was possible to test very interesting and complex phenomena for those days.

There is no better way to begin to describe the scientist as the "Father of Physics", as well known. Importantly, all their studies and works are key in understanding and research of the Earth. "Newton scored his intelligence and his interest in science with the discovery of the laws of mechanics and universal gravitation, his explanation of the decomposition of light in different colors and for his outstanding work on algebra and geometry, and the invention of differential calculus (LaWebdeFisica, 1993)”. Other discoveries or inventions are: “reflector telescope, optical phenomena such as interference rings, the disc of white light and the vacuum tube to demonstrate the falling material (LaWebdeFisica, 1993)”. Indeed we must recognize that Isaac Newton has also worked with the study of many branches of science and its contribution to future generations is formidable. Many questions we had if their findings and publications were not certain or perhaps unknown.

The Law of Force, which explains how vary the properties of the body to apply force or otherwise as seen from the definition of force is my favorite one. It is explained as follows: is understood that the time variation of the moment is force. Assuming that the mass does not change, this change over time is velocity, and the change of velocity with respect to time is acceleration. That is why it is said that force is the product of mass times acceleration. Perhaps it is simpler to understand, what is interesting in this whole affair is that Newton had the ability to represent it in writing and explain it to then we study it more deeply and understand from the root; so clever and so professional that the scientist, despite the years that have passed and the advances in technology, have achieved their current and credible findings to scientists of our day.

It is interesting to note personalities as important as Newton. His contribution to education is a cornerstone for further research now because despite all the modern inventions and innovators of our time , there are always questions without responses to the recognition of new figures which have just as Newton the potential to get answers.

"What we know is a drop of water, what we ignore is the ocean." Isaac Newton.

References:

LaWebdeFisica.IsaacNewton.

2011-05-05T18:17:00.000-07:00

Is physics an unknown science?

Giovanni Vega Meléndez

When we define physics, we can say that is a science that involved the matter and the energy and how they both interact; also some very important branches are grouped such as acoustics, mechanics, thermodynamics, and cryogenics, among others. There are various fields in physics such as atomic physics, nuclear physics, solid-state physics, particle physics, plasma physics, and some other modern extensions. Moreover physics study the universe and how it behaves. This science is very important for all work related to engineering, for mathematics works and all works that are related to the universe. Despite the fact that Physics is one of the oldest educational field, in the public schools of the town of Juana Diaz is simply an unknown science. I realize an investigation in the public middle schools of my town of Juana Diaz, where I discovered that none of the seven middle schools teach the physics course (Maximo Donoso Sanchez, Josefa Cangiano Toro, Felipe Colon Diaz, Zoilo Gracia, Luis Muñoz Marin, Salvador Busquet, tomas Carion Maduro). Otherwise in the four colleges; in three of them (Carmen Belen Veiga, Luis Llorens Torres, Maximo Donoso Sanchez) teach the course, in the other college did not teach physics (Luis Muñoz Marin). In those three before mentioned I realize an investigation by means of a questionnaire of four questions to measure students’ knowledge related to physics. These questions are: first question was; What is physics? Only the 7 % of the respondents gave me a concrete answer. The other 93% do not offered a correct answer or not answered. Second question is: How physics relates to math? Only the 20% of the respondents gave me a concrete answer. The other 80% do not offered a correct answer or not answered. Third question was: Mention at least two of most important physicists in the history of physics. Only 20% answered correctly. Another 11% mentioned only one and the remaining 64%did not answer this question correctly or simply not responded. Some of the physicists more mentioned were: Albert Einstein, Isaac Newton and Galileo Galilee.

The fourth question was: Mention at least three terms related to physics. Particularly in this question 18% answered correctly. Another 23% did so partially correct. Other 59% did not respond correctly or simply did not respond. This questionnaire was delivered to the mayoralty of this town with one intention, if they do nothing in this regard, this case will be introduced directly to the office of the Secretary of Education. If not occur anything related to this, will be the press who will be responsible for informing the people about what happening in the education agency of this country and insufficient educational distribution that exists in the education department .

This investigation, in spite of its simplicity shows that in the public schools of the town of Juana Diaz is not being teaching adequately such important science. We should take action on this, because it affects future learning of the student and also to our next generations. This is a knowledge deficit in the public schools, not only in this town, also in all public schools of Puerto Rico. We do not take into consideration that everything has a direct relationship with the physics and its branches. Analyze by yourself, is the physics an unknown science for you?

2011-05-05T18:12:00.000-07:00

Is invisibility a possibility?

Alicia M. Surillo

Since a very long time ago, people started to think about invisibility as something amazing and powerful that they would love to achieve someday. Everyone could use invisibility to accomplish something whether is was good or bad. For example, a thief could use invisibility to make impressive robberies while a policeman could use it to catch a criminal without having him run away. In fiction movies nowadays, we see different methods in which characters become invisible such as invisibility cloaks and potions. Is there really a cloak or potion that can make an object invisible? Physicists have dismissed this possibility by stating that an invisibility cloak would violate optics laws and would not follow the properties of matter.

This physicists' statement was questioned when in 2006, a group of researchers at Duke University in Durham, North Carolina, and Imperial College in London challenged the conventional optics laws and made an object invisible to microwave radiation by using metamaterials. The existence of metamaterials had been referred to as “impossible” by optics text books (since they would violate optics laws). As a result of this discovery, physicists were forced to rewrite optics text books. Metamaterials are substances with optical properties not found in nature, created by embedding very small implants within a substance to force electromagnetic waves to bend in unorthodox ways (the scientists from Duke embedded tiny electrical circuits with copper bands). The electrical implants on the copper forced the path of the radiation to be in a specific way. Michio Kaku's book, “The Physics of the Impossible” , compares this microwave radiation flow with the way a river flows around a rock. It states, “Because the water quickly wraps around the boulder, the presence of the boulder has been washed out downstream. Similarly, metamaterials can continuously alter and bend the path of microwaves so that they flow around a cylinder, for example, essentially making everything inside the cylinder invisible to microwaves.” Scientists put the metamaterial to the test by inserting a copper ring inside the microwave device. Only a tiny shadow of the ring was reflected, which means that the ring was nearly invisible to microwave radiation.

The most impressive property of metamaterials is their ability to change the “index of refraction”. The index of refraction of an object is how light bends as it passes though it, specifically for transparent objects. For example, as light passes through water and glass, we can see that it bends, taking different paths. Refraction happens because of the larger concentration of particles in a solid or liquid (and even gas) from that of empty space, through which light has to find its way. As a generalization, we can say the denser a transparent medium is, the higher its index of refraction will be. Some common index of refraction are: 1.00 for empty space, 1.0003 for air, and 1.5 for glass. The index of refraction is usually a characteristic of the substance, it does not change throughout it. However, if it could be controlled, light would follow different paths through the substance and would end up roaming through it. Scientists believe an object can be invisible by controlling the index of refraction inside a metamaterial in a way that light passed around the object. To achieve this, the metamaterial has to have a negative index of refraction (which is one of the rare characteristics metamaterials have). Again, optics text books stated that it was impossible for an object to have a negative index of refraction, so they had to change that too.

Many journalists have asked metamaterials researchers when are invisibility cloaks coming to sale, to which they have answered, “Not anytime soon”. Although the assembly of metamaterials is a huge step into accomplishing that ability that everyone wishes to have, there is still more research and discoveries to do. But, who knows? We could possibly be closer than what we think to wearing one.

Reference:

Kaku, Michio. Physics of the Impossible. 1st Edition. New York, NY: Anchor Books, 2009.

2011-05-05T17:54:00.000-07:00

Guitar Strings and Physics

Allen A. Rodriguez

Probably everybody in this world knows what a guitar is and probably everybody knows how it sounds. It’s a really interesting and beautiful instrument but surely not everybody knows how the sound in the guitar works. As every phenomenon in this world, the sound n the guitar surely has an explanation in the world of physics. Why does all the classical and acoustic guitars have the same form or similar? Why the structure in the inside has to be specific? Why the tools in the guitar changes if the material of the string change? All of these questions may arise to the user or just to an admirer, and as purpose of this work we’ll try to explain it in a new world of vision… physics.

Guitars are made mostly from wood. Wood, apart from giving a great image to the guitar, creates a chamber of resonance that makes the sound wave of the guitar even clearer. It all depends on the wood, that’s why the best the wood, the more expensive the guitar. We’ll focus on how everything in the guitar has to do with the sound of it. They’re two types of strings, the metal strings and the nylon string. The first one is clearly metal and the second one is a synthesized polymer, is “plastic”. Structure on guitar may vary according to the type of string because when tension is applied to both of the strings, metal exerts more force than nylon. This means that if we put metal strings into a nylon guitar, the guitar will break up, because tension was creating excessive pressure to the bridge of the guitar. Now that we’re related to basic materials let’s jump to how is all combined to make the guitar sound.

Guitar has six strings all of them with frequencies of: 82 Hz, 110 Hz, 147 Hz, 196 Hz, 247 Hz and 330 Hz. Strings, depending on material, are stretched in the guitar in order to produce the sound waves that moves into the body of the guitar. Inside they set up an internal resonance in the chamber made up by the body of the guitar which creates vibrations inside of the body that makes compression of air and eventually go out in for of sounds to our ears. Inside the body, if we take a closer look to the internal structure, the guitar has an empty space and some of them have “columns” of wood. This structure is completely on purpose, it’s made up in order to create more vibrations and make a clearer sound. The sound, which is transfer to the wood via the bridge, creates a pattern on the face of the guitar and that’s were sounds propagate. This is when wood roles an important paper, because of the propagation of sound, the sound propagates differently through materials of different densities. If the material is too dense, the sound is transmitted with less energy.

But an interesting observation could be made and furthermore a theory can be extracted. When the strings are exposed to tension, the process of tuning begins. As the tension is applied to the string the sound becomes more and more sharp and acute. This is exactly what happens when we take a rubber and stretched it, if we touch it, it will sound and the sound will be acuter if we stretch it even more. So we can establish that: Then sound in a string is directly proportional to the tension applied and inversely proportional to the length of the string. This we can see it in the string of a guitar vs. a rubber. Sound is attached to the tension that is applied to it. That’s what we call tuning of a guitar.

All of the components in a guitar are important in the role of the sound but tension is what puts everything on work. Tension is the magnitude of the pulling force, which is exactly what we see in the structure of the guitar. The guitar pin is what exerts the force and the string is what experiences the tension. The more tension, the more steady the string and a more acute sound. It’s important to also remind that every string has its maximum tension capacity, even the sound is directly proportional to the tension, tension applied to the cord has to be within the accepted range of tension. This behavior is also known as the module of elasticity. When the string or cord reaches the maximum tension capable, it will break. It’s really interesting to know how this entire system works. But guitars aren’t the only instruments with strings; there is lots of other instrument that have strings such as violins, Chellos, harps and a lot’s of other.

It’s very cool to know how to use one of these instruments, but is amazing knowing hoy does the instrument work in the world of science, specially physics. It’s like Frank Wilczek said once: “In physics, you don’t have to go around making trouble for yourself – nature does it for you”.

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Sources Cited:

1. Billington, I. “The physics of the guitar”. http://ffden-2.phys.uaf.edu. Physics 211x. 1999. Web

2011-05-05T17:41:00.000-07:00

Physics and its dance arts

Cyd M. Zamot

Ever since I was a little girl I always liked to dance, but more to see the dancing ballet. I always found it interesting, intriguing and curious. Ballet is the art of precision and dance. My curiosity as a child always made me ask how these people (the ballerinas) made jumps and maneuvers so perfectly. As I grew, I understood that for the ballet, more than ability they needed a series of knowledge. But what type of knowledge? They needed to have some physics knowledge.

How do we combine physics and ballet? When I made this big question I didn’t know the answer until I took my first physics class in high school. How do the dancers rotate on its axis? How can they make jumps of over 180 degrees? How can the dancers perfect their techniques just knowing about physics? Those are more questions that I asked myself. I learned that dancers can make those movements so perfect by the laws of gravity, dynamism and energy.

Dancers support their force on a support point which is the floor, balancing their weight; thus having balance, obtaining therefore a uniform circular motion on its axis. But even more; using physics, it is estimated that to maintain this movement (the circular motion) the dancer must have a minimum speed of 2.4m/s and a maximum of 5 m/s to maintain the balance. To make the jump of 180 degrees, the dancers have to open their legs with a force of 10 N. We also have to think about the weight. The weight is the measure of the force that exerts the gravity. Another thing is the shoes that the ballerina is wearing. The ballet slippers are made of a special material that makes the dancers use all its weight exerted a support point because the dancers need to turn over 360 degrees on its axis.

We can see more concepts of physics in the ballet. Examples include projectile motion, center of mass, kinetic energy and momentum. The projectile motion is any object which projected once continues in motion by its own inertia and is influenced only by the downward force of gravity; it can be seen in the pirouettes of the ballerinas. The center of mass of any homogeneous symmetric object is located on an axis of symmetry, which is classical at the ballet when they supported on a specific point of their body and rotate around its axis of symmetry. Also we see in the ballet the kinetic energy which is the work required to accelerate a body of a given mass from rest to the speed that it has. Last but not least we have the momentum which is the amount of movement, or is the product of body mass and speed at a given instant

I finally answered my biggest question: How do we combine physics and ballet? Physics is combined with ballet because each movement exerts a certain force, which applied to physics would help each of the ballerinas to make better moves and check what steps are wrong. So finally, what is ballet? For me ballet is de dance of physics. Is the combination of forces, laws another physics things that create a scenic and dance art, the ballet.

Reference:

Giancoli, Douglas C. Physics for Scientists & Engineers with Modern Physics. 4th ed. Vol. 1. Upper Saddle River, N.J: Prentice Hall, 2009.

http://es.wikipedia.org/wiki/Ballet

http://www.medellin.edu.co/sites/Educativo/Docentes/feriaexplora/Fsica%20y%20Astronoma/La%20F%C3%ADsica%20en%20el%20Ballet.pdf

2011-05-05T12:55:00.000-07:00

Black holes a basic component of the universe

Francisco J Vergara Ortiz

When you think about black holes, many things come to your mind, some are the product of movies and television created by Hollywood, others are myths that people say almost every time, that a black hole conversation came up to the table. It is say to be cosmic vacuum cleaners and some people says that they are portals to others universe, or other dimension. Well that’s just myth, assumptions, and theories because no one has ever been in a black hole. But what a black hole really is? How many types of black holes we know and what is the Schwarzschild radius? And if they’re the dark black in a black sky (universe) how we know they exist?

In theory a black hole is so dense that even light can’t escape from it, this happens because of gravity as we learned in general physics every object exert a gravity force into another object, when an object is so dense everything near it radius of gravity will collapse into it by the law of gravity, and that is what a black hole is, a body of mass so dense that even light that is called photon which are mass less can’t escape from it. Also in principle every object can be made into a black hole by reducing that object to cero volume, but conserving its mass and gravitational force, when this happens the object undergoes into gravitational collapse, it attract itself, compressing his mass into a singular point. This black hole will have a gravitational self attraction called the Schwarzschild radius. But the only object that can become a black hole by itself are stars with 10 to 15 times the mass of our sun when they explode (die) they collapse onto itself and forms a stellar black hole, a really little one with only a few tens kilometers of Schwarzschild radius but with three to ten times the mass of our sun.

As we know there are two types of black holes the stellar one that is when a supernova dies and the super massive black holes (SMBHs) this last ones are still a mystery, no one knows how they form, but it’s believed to be the center of almost every galaxy including our milkyway galaxy. (SMBHs), weights up millions or billions times the mass of our sun. But they are really cosmic vacuum cleaners? The answer is no, to be sucked into a black hole you must cross the Schwarzschild radius this radius can be calculated by this equation R=2GM/c^2 where c is the speed of light, M the mass, and G the gravitational constant. If for example a black hole has the mass of our sun, his Schwarzschild radius will be only 3 kilometers, and in order to get sucked in you must be at least 3kilometers from its center. But there are black hole out there with billions times the mass of our sun. At this time the biggest one our scientist have seen is about 18 billion the mass of our sun called (Oj 287), I use this formula to calculate his radius and the result was amazing about 53 billion kilometers, to get and imagination of how big it is if every star where a kilometer it would be 0.18 the number of stars on our galaxy, and to get a direct comparison this radius is about 8 millions the time of our planet radius.

Another fact that I found interesting is the force it exerts on another objects lest take the same black hole and apply the law of universal gravitation by Newton. If our planet where on the border of the Schwarzschild radius of this monster the force that it will exerts will 5.06845 x 10^27 Newton onto our planet, that’s a lot of force maybe one of the most powerful things in the universe are the black holes, if they are not. They are so powerful that they are what bounds a galaxy and makes them move around it, because they function like stars, like our sun domains our planet system a black hole domains the galaxy.

How do we know they exist, first of all it is impossible to see this stars with the visible spectrum because light cannot escape from it, but for example is there is a normal star near a black hole the black hole will pull matter towards him, in this process of taking matter out of the nearby star or stars, the black hole gains kinetic energy, this energy is so big that the atoms gain millions of Kelvin and when this happens the black hole emits x-ray in the form of jet out to the space. This jets heat up the surrounding and prevents gas to collapse into the center, and that is what we see and know they exist.

We know what are they, how them work, and a lot of things that still are a mystery. But black holes are basic things in the universe, as we learned they are not cosmic vacuum cleaner sucking everything in their way. First and object must cross his Schwarzschild radius, and the x-rays they produce prevent gas from falling inside it. Allowing nearby galaxies to form and growth, after all there is an injured and beneficial part of this, and our sun, our planet, and ourselves seems to be the beneficiary of this far a well monsters.

References

"Black Holes." Imagine The Universe! Home Page. Web. 23 Apr. 2011. .

"Imagine the Universe News - 10 April 2003." Imagine The Universe! Home Page. Web. 23 Apr. 2011. .

"Universe Forum--Black Holes--What Are They?" Center for Astrophysics. Web. 23 Apr. 2011. .

Giancoli, Douglas C. Physics for Scientists and Engineers. Fourth ed. Upper Saddle River, N.J: Pearson/Prentice Hall, 2008. 140-41. Print.

Giancoli, Douglas C. Physics for Scientists and Engineers. Upper Saddle River, N.J: Pearson/Prentice Hall, 2008. 1208-209. Print.

2011-04-27T19:39:00.000-07:00

New enigma in physics: Dark Energy

Kyshalee Vázquez

Common beliefs concerning the universe are that it is stationary and mainly composed of everything we can perceive with our senses. Actually, when we think about the universe what comes to mind may be stars, planets, galaxies, perhaps black holes and nebulae. However the National Aeronautics and Space Administration states that these celestial bodies only compose less than five percent of the universe, a miniscule portion of such a grand cosmos. Then, what is the remaining portion of the universe made off? And if the universe isn’t stationary, what is causing its motion?

After the Big Bang the universe started to expand, and all the matter was close enough to be pulled together by gravitational forces to form the universe we study today. Astronomers knew the universe was still expanding from the energy of the Big Bang, but it was believed that this expansion was decelerating. This deceleration was attributed to the fact that the universe had enough mass that would pull on each other by gravitational forces, and therefore slow down the process of expansion. However the rate of this deceleration was unknown and consequently two groups of astronomers searched for answers.

The idea was to find Type Ia supernovae because they reach the same luminosity when they undergo a thermal explosion. By determining the brightness and measuring the redshift it is possible to know the distance of the supernova and how long ago they occurred. Of course this process took a few years because Type Ia supernovae are hard to come by, for their brightness only lasts a few weeks. With the information gathered after this long research process it was evident that the stars were farther away than they should be, if the universe were slowing down. These two groups of astronomers were confused since this information indicates that the expansion of the universe must be accelerating and not decelerating.

As it is usual in science, another question emerged. Why is the expansion of the universe speeding up if it has enough mass to slow it down? A new factor had to be added to this quest that was not considered by these astronomers at first, but it is believed that it was considered by Albert Einstein when he introduced the cosmological constant in is general relativity theory. Astronomers thought that this new factor, called dark energy, must be a kind of repulsive force that keeps separating the galaxies farther away expanding the universe.

Although dark energy keeps separating these immense groups of celestial bodies from each other, we shouldn’t worry about it separating Earth from the Sun, because there is yet another presence that like dark energy we cannot perceive with our senses, called dark matter. Dark matter is held responsible for the formation of galaxies, because there is so much dark matter around the celestial bodies creating a gravitational attraction additional to the gravitational pull they already have as masses of normal mater. It is not likely that dark energy will separate the planets or stars in a galaxy itself due to this dark matter. Both dark energy and dark matter are relatively new to our knowledge and very little is known of them.

Finally after this series of discoveries, scientists have concluded that dark energy and dark matter were created in the Big Bang along with normal matter. Because the universe was smaller, all the matter was closer and the force of gravity was greater than dark energy, so the expansion of the universe was slower. As the universe kept slowly expanding dark matter and gravity formed the galaxies, continuously segregating them farther apart. When dark energy overwhelmed the gravitational force, due to the growing distance, the universe started accelerating in its expansion.

Illustration shows the changes in the rates of expansion since the universe’s birth.

Bibliography

Netting, Ruth. "Dark Energy, Dark Matter." NASA Science Astrophysics. Web. 15 April 2011.

Smale, Alan. "Dark Energy." Imagine the Universe. 29 October 2009. Web. 15 April 2011.

Villard, Ray and Riess, Adam. "Refined Hubble Constant Narrows Possible Explanations for Dark Energy." HubbleSite. 7 May 2009. Web. 15 April 2011.

2011-04-27T13:34:00.000-07:00

Earthquakes: “A real threat that lurks in our future”

Luis M. Rolón Luna

Recently we may have seen or heard the word earthquake by the media and witnessed its powerful capabilities here on the island and throughout the world. Places like Haiti, Japan, Chile, etc. have lived the devastating power and energy an earthquake possesses. A quake is a shock of the land that takes place due to the shock of the tectonic plates and to the liberation of energy in the course of an abrupt reorganization of materials of the terrestrial crust when surpassing the state of mechanical balance. Most important and frequent they take place when accumulated elastic potential energy in the gradual deformation of contiguous rocks is freed to the plane of an active fault, but also can happen by other causes, for example around volcanic processes, or slope movements.

How are trembles produced? They are vibrations of the land caused by an abrupt liberation of energy coming from the edges of tectonic plates. The tectonic plates hit to each other and produce liberation of energy as a result of the efforts that they were supporting. The point in which the earthquake in the surface is detected is the epicenter and the point where the earthquake takes place is the hypocenter. In the hypocenter, the waves disperse towards all directions. First that arrives are the waves P (primary), followed of waves S (secondary). They are different from others in the speed of propagation and in the possibility of crossing surfaces you eliminate, like the external nucleus. Primary P waves are those that are detected first in the seismograph. Also they are waves L, the superficial ones, these they are in surface and they are most destructive, they are also but the slow ones and they are those that cause the damages.

How do quakes affect a building? Most of the earthquakes are the result of a fast movement throughout the plane of faults in the terrestrial crust. This sudden movement of the fault publishes a great amount of energy that travels through the Earth as a seismic waveform. The seismic waves travel great distances before losing most of their energy. At some time after their generation, these seismic waves will arrive at the Earth surface, and to put it in movement. When this movement of the ground happens under a building and if it is strong enough, the creation of movement commences, beginning with the construction of the foundation, and transfers the movement through rest of the building in a very complex form. When the content of frequency of the movement of the ground is centered around the natural frequency of the building, it is said that the building and the movement of the ground are in resonance with each other. The resonance tends to increase or to amplify the answer of the building. Due to this, the buildings suffer the greater damages by the movement of the ground to a frequency near or equal to their natural frequency.

This is why we must create a seismic conscience in Puerto Rico because we live in a highly active island where earthquakes of different magnitudes occur every day. I greatly recommend that we seek education in what to do before, during and after a quake. This way we can be prepared if the situation presents itself and possibly help others. You can also go to this website www.ciapr.org which is the cybernetic page of the School of Engineers and Surveyors to find orientation and the seismic plan for Puerto Rico.

References:

1. es.wikipedia.org/wiki/Terremoto. Web. April 22, 2011.

2. http://www.angelfire.com/ri/chterymercalli/. Web. April 22, 2011.

2011-04-27T13:20:00.000-07:00

“Beam me up, Scotty”

Jorge Gabriel Concepcion Sanchez

The impossible is that which is considered to be unfeasible or unattainable. We cannot flap our arms and fly, we can’t hold our breath for hours underwater and we cannot see in the dark. Even though these feats are considered impossible to an ordinary human being, through the use of science and technology we human have conquered the skies, journeyed to the watery depths of the ocean and peered into the darkness of the night without the help of light (visible light to be exact). We have seen that as time goes on and technology becomes more and more advanced, science is able to blur the line between the impossible and the possible, turning science fiction into science fact. Dr. Michio Kaku, theoretical physicist and Co-founder of Grand Unified String Field Theory, uses his book “Physics of the Impossible” to demonstrate the underlying physics behind many of the “impossibilities” that today’s scientists toil over so that we may have a better understanding of which are realistically within the reach of our civilization.

From force fields to parallel universes and perpetual motion machines, Kaku divides the impossibilities that are throughout his book into three categories: Class I, II and III impossibilities. The first refers to “technologies that are impossible today but that do not violate the known laws of physics” and that might become possible in this century or the next. The second concerns those technologies that “sit at the very edge of our understanding of the physical world” and that might be possible in a thousand to a million years. Lastly, Class III impossibilities apply to technologies that “violate the known laws of physics” and that if possible, “would represent a fundamental shift in our understanding of physics.” Intrigued? I know I was. Such things had always caught my attention but I would dismiss them as just that, interesting queries that are ultimately meaningless because of their improbability. It was ignorant to do so, however. Even though Kaku makes the physics behind the impossibilities easy to understand, Class II and III impossibilities are very abstract and my limited knowledge in theoretical physics prohibits me in properly explaining them. As a result, I have chosen to explain the Class I impossibility that intrigued me the most: teleportation.

Teleportation is the capacity to instantly move objects from one place to another. Throughout this semester, we have journeyed through the world of Newtonian physics as objects move because they push and pull on each other. If an object wants to go somewhere, a force has to be exerted in order to move said object to the desired location. Makes sense, right? Well, there’s this thing called Quantum Theory and it doesn’t care much for your common sense. In Quantum Theory, particles like electrons can exhibit wavelike behavior as described by Erwin Schrödinger’s famous wave equation. It may sound weird but electrons can be described as waves of probability which “tell you only the chance of finding a particular electron at any place and any time.” This probability pertaining to electrons is known as the uncertainty principle which states that “you cannot know both the exact velocity and the position of an electron at the same time.” Therefore, in the strange world of the Quantum, it makes perfect sense for an electron to be at more than once place at a time and objects are described as the sum of all their possible states since there is no way to know for sure where its electrons are located. This might seem counter-intuitive since the physical world is full of objects that don’t spontaneously disappear and reappear such as our bodies. The human body however, contains trillions upon trillions of electrons and all the quantum events taking place inside our body even out over time giving it the appearance of being solid. Interestingly, if we were to calculate the probability of our body disappearing and reappearing in the next room, we find that we would have to wait “longer than the lifetime of the universe” to witness such a quantum event. This type of event is impossible under Newtonian physics yet is possible in Quantum theory, albeit the probability for it taking place is unimaginably small.

Einstein didn’t like probability and chance being introduced into the heart of physics once saying, “For my part, at least, I am convinced that [God] doesn’t throw dice.” He and two of his colleagues even performed an experiment in an effort to disprove Quantum Theory based on the idea of quantum entanglement. This is the concept that “ particles vibrating in coherence have some kind of deep connection linking them together.” This means that if two electrons are coherent, meaning they are vibrating at the same frequency, then what happens to one will affect the other regardless of the distance between the two since “there is still an invisible Schrödinger wave connecting both of them”. Not surprisingly, Einstein was unable to disprove Quantum Theory through quantum entanglement and ironically, it is this same concept that is the basis for teleportation.

Quantum teleportation is weird in the sense that an object doesn’t magically appear from one place to the other, rather its information is the one being “teleported”. To illustrate this, Kaku uses the example of three atoms A, B and C. Suppose we want to transfer the information from atom A to C; also suppose that B and C are coherent. If atom A comes into contact with atom B and becomes coherent, then A’s information is passed to B but since atom B was already entangled with C, then A’s information ultimately ends up in atom C. Strangely enough, if an object were to be teleported, it technically has to die before its information gets transferred to elsewhere creating the exact same object with the same information. It may sound weird but scientists have already been successful in teleporting particles in this manner. One of the most astounding achievements being the entanglement of a light beam with a gas of cesium atoms and teleporting this gas for about a half yard!

Teleportation involving entanglement might not be the as “science-fictiony” as one may had hoped but a way to teleport that is truer to the Star Trek tradition has already been discovered and therefore is called “classical teleportation”. It involves the use of a “Bose Einstein Condensate” or a BEC, one of the coldest substances in the universe. Some of the coldest temperatures in nature can be found in outer space ranging around 3 K above absolute zero (this is due to the residual heat from the Big Bang). A BEC however is “a millionth to a billionth of a degree above absolute zero”, a temperature only producible in a laboratory. BECs are important because at so low a temperature, atoms are at such a low state of energy that they vibrate in unison and therefore become coherent. Essentially, a BEC can be seen, as Kaku comically puts it, as “one gigantic super atom” since the wave functions of the atoms imbricate over one another. The first step in this method of teleportation involves shooting a beam of matter at a BEC where both consist of the same type of atom. As the beam comes in contact with the BEC, the beam’s atoms tumble down to the lowest possible energy state releasing energy in the form of light. Curiously enough, this light carries all the quantum information of the original matter beam so if then the light beam comes into contact with another BEC, a new matter beam identical to the original one is created.

Quantum teleportation is a technology that is deeply intertwined with that of quantum computers which are a new breed of computers that use the concept of quantum entanglement to make calculations. The reason today’s computers are so advanced is because their progress is based on the shrinkage of their components. Their components however cannot shrink beyond a certain threshold because then the uncertainty principle kicks in. Quantum computers are then the most likely candidates to replace their silicon based brethren in the near future. Besides all of the progress that has been made in this field, we are far away from having a personal quantum computer and teleporting ourselves to the mall. The most daunting obstacle is maintaining coherence between a large number of particles since the tiniest vibration is capable of causing decoherence. Quantum computers would require billions of constantly coherent particles in order to compete with today’s computers let alone how much it would take to teleport macroscopic objects such as a human being. Even though there are technical difficulties regarding teleportation, it is exciting to know that it doesn’t violate the laws of physics in any shape or form.

Einstein once said, “If at first an idea does not sound absurd, then there is no hope for it.” Making the absurd possible lies at the very pinnacle of scientific progress and it’s this absurdity which gives our civilization the potential for progress. Teleportation is just the tip of this magnificent iceberg and other even more exciting technologies might be hidden beneath the waves. Rightfully so, our future as a species may lie in the absurdity of such technologies.

Reference:

Kaku, Michio. Physics of the Impossible. 1st ed. New York, NY: Anchor Books, 2009.