The Speed of Light

Sam E De La Torre Baba

The speed of light is the maximum velocity that anything can travel. The speed of light is commonly referred to as c and is 299,792,458 meters per second. This speed not only refers to the speed of light travels, but also the speed of any massless particle will travel. As of now, there are only two massless particles which are the photons and the gluons. Neutrinos (which as of recently have been proposed that they can travel faster than the speed of light) are assumed to be massless, however, the model for their oscillations require them to have nonzero masses. The change in which a gravitational field propagate will also be equal to the speed of light.

In our everyday lives, we observe light because light is what allows us to see. The light we see everyday though will not travel at the speed of light. This is because the light we observe has to travel through transparent mediums such as air, glass, or water. Every substance has its own refractive index which describes how light propagates through a certain medium. When light enters a transparent medium, light's path will be distorted, therefore, the speed in which light propagates through the mediums we see everyday will be slightly slower. The speed of light through this mediums is still very close to the actual speed of light due to the amount in which it slows down is almost negligible and will result in such a speed that can be considered instantaneous.

In electrical engineering courses, students are thought to assume that if all elements of a circuit are ideal, than one is to assume that a current can be found on all elements of the circuit immediately upon applying a voltage. By knowing light has speed, we know this is not precisely, but due to lights incredibly high speeds, this is negligible and circuit analysis results in being a very important tool for electrical engineers.

So, light seems to be of such high speed that it can be considered instantaneous. One can react to things in an efficient manner such that the speed of light can be unaccounted for. What if we are to observe this in a macroscopic way? The easiest way to do this is by going outside and observe the night sky. There are more stars than can be counted with an estimated 100 sextillion in our universe. To see these stars, light must have traveled from its origin (in this case the star) all the way to our planet. In this case, the star is very far away. So far away, that light can no longer can be treated as instantaneous, not even close to it. A unit of measurement was even created for us humans to be able to contemplate the vast distances between these celestial bodies, the light year. The light year is a unit of length which is equivalent to the distance traveled by light in a a single year.

Since these stars are so far away, we would have to go faster than the speed of light to get to them. But, I just stated that the fastest an object can go is the speed of light. So what would happen if one would go faster than the speed of light and why can't I go any faster? Lets remember Einstein's famous formula E=mc^2. This results in a relation between energy and mass using the speed of light as a constant. This equation allows us to conclude that the more energy an object has, the heavier it becomes, and can it can even be argued the more mass it has. So lets propose that one is riding a car that can go tremendous speeds that can is able to get close to the speed of light. As one starts passing the sound barrier, you can feel a force towards you, pushing you towards your seat. Faster, faster and faster and your getting closer to the speed of light. Everything is significantly heavier which results in your hair weighing much more than what you used to weigh before going the speed of light. As your speed approaches the speed of light, your weight will become infinite. To move an infinite amount of weight will require an infinite amount of force to move. This is the bottleneck. There is no way to obtain an infinite amount of force thus obtaining a speed faster than the speed of light impossible.

Magnetism and it Uses

Elmer Melendez Maisonet 

Today magnetism is a very important resource; it could be an alternative to help in the Global Warming crisis. Electric and hybrid motors could be an excellent alternative. Magnetism is a property of materials that act in response to an applied magnetic field. A magnetic field is caused by an electric current but it can’t be seen, it is an invisible physical phenomen. A magnetic field is determined by the force produced on a loaded particle moving through a magnetic dipole such as a permanent magnet. Ferromagnetism caused permanent magnets to have a determined magnetic field. However, they are two different types of magnetism. Paramagnetism is attracted to a magnet field. While diamagnetism is driven off by a magnetic field. Other magnetisms have a more complicate relationship when applied to a magnetic field. Non magnetic substances are substances that are not affected by magnetic fields. Some non magnetic substances are copper, aluminum, gases, and plastic. Some material exhibit magnetic properties depending on the state they are. Pure oxygen is a good example; it exhibits magnetic properties when cooled to a liquid state. However, the magnetic property not only depends on the material’s state, it also depends on the temperature. A material may exhibit more than one form of magnetism depending on its temperature or pressure.

An electric motor is all about magnets and magnetism. A motor uses magnets to create motion. As proved, opposites attract and likes repulse. If two magnets have their ends marked north and south, as consequence the north will attract the south. In the inside of an electric motor, the attracting and repelling action will create a rotational motion. An electric motor consists of three main parts: the armature, the brush and the commutator. The armature is composed of rectangular coil made of copper wire wounded on an iron center. Coil is attached to on an axle and then placed between a magnet’s poles. To reverse and ensure the direction of the flow current a commutator is needed. A commutator consists of a copper ring divided in two parts. The divided parts are isolated from each other and placed in the motor’s axle. The ends of the coil must be soldered both rings. They move along with the coil. The commutator rings have to be connected to a battery but the wires from the battery are not directly connected to the rings. They are connected to the brushes. The brushes are strips made of carbon that push against the split rings. Both rings rotate in between the brushes. All carbon brushes are connected to an electric source. Finally, a magnetic field is generated around the armature when the coil is powered. The mechanical work is seen when the left side of the armature is pushed away from the left magnet, drawn towards the right and causing it to rotate. This motor as everything had it pros and cons. But it has more pros that cons. The pros of this motor are that it helps the environment, less expensive because you do not have to spend money in gas and it is easier to repair. And finally the cons are that it has a limited time of use because you need to charge it and that it is very silent and a blind person might not hear the motor and it could cause an accident.

Physics in our World

Victor E David Cruz

Since the first day of humanity, we have look forward to advance and evolve in every way possible. In the beginning our minds were full of question, so many that seems impossible to answer all of them, but with time we have found an explication to all of those question or at least to most of them. And the secret to success is Physic; this science is the main responsible for our knowledge about mostly everything. It explains how the moon behaves, how the world was created, it has been used for wars as lethal weapons and used to give place for maybe the greatest invention of all time: the light.

For this reason is very important to understand that physics is in our daily life, we used constantly and technically every day. For example we can relate the concepts of mass, force, and acceleration with cars, in sport like boxing, basketball, tennis, etc. The light for once, we cannot live without it, not nowadays. It was invented for maybe the greatest inventor of all times: Thomas Edison. Edison in 1879 used low current electricity along with a small carbonized filament, and an improved vacuum inside the globe, to give birth to a reliable source of light. The invention of the light bulb gave room to many other related inventions like: the devices for maintaining constant voltage, the parallel circuit and light sockets with on-off switches. But the big thing here is to realize that while Edison holds a world record of approximately 1,100 inventions, what he used in order to create all of his invention is known as Physics and as difficult that might appear to comprehend all of this an explanation of how all this works can be found in a Physics text book.

It is obvious to us now that Physics have been very useful to us lately, but it also has a dark side. For instant, Einstein’s brilliance was use to produce the atomic bomb. The simple equation E= mc2 which explains that energy equals mass times the speed of lights squared, is the responsible to the concept that a very tiny mass could be use to produce a lot of energy. But to keep it simple, I will show you how we using Physics are hurting not only us but our planet. The first thing that might come to your mind is the global warming, but this is not the only matter to concern. In case you do not know as time pass by there are less start in the sky, why? Because of light pollution, which is the emission of light output from artificial sources this is generated from an inappropriate application of exterior lighting products.  This is one of many ways that we are using Physics in context, in this case negatively.

So next time you find yourself in a Physics course think that what your professor is about to say is related not only to you but to many others. It might be difficult to erase the concept of light as an electromagnetic wave and its formulas, but remember no matter how hard Physics seems to be, nothing is new, we use it every day.

Energy

Leonardo Hernandez

One of the most fundamental concepts of thermodynamics and one of the most significant

aspects of engineering analysis is energy. After Newton formulated the laws of motion which led to understanding the concepts of kinetic energy, potential energy and work, this laws then led to a broad definition or understanding of the concept of energy. But what is energy? Some say energy is the “ability to do work”. Doing work basically means to move a system, to heat a system, to lift a system, basically to change a systems energy state you have to apply work.

Energy is like the air, it is all around us even if we can’t see it. It is being used in almost every

aspect of our lives. Every time you turn on the lights, while cooking your using energy, even that food you just cooked is a form of energy. Energy powers your car, your air conditioner, your television and the list goes on. There exist many different forms of energy. Some of them are: solar energy, mechanical energy, chemical energy, energy in the form of heat, nuclear energy and magnetic energy, just to name a few.

It is known that matter can be changed into energy and energy into matter but the total amount stays the same. The law of conservation of energy states that energy may neither be created nor destroyed. Therefore the sum of all the energies in the system is a constant. In other words what the law of conservation says is that energy can be transformed from one form to another (e.g. the stored chemical energy in a battery is transformed into electrical energy to power a flashlight) but the amount of said energy will stay the same because energy cannot be destroyed nor created.

The most widely used form of energy since the industrial revolution has been oil (a type of fossil fuel). Oil is refined into petroleum products and those products are the ones that have a daily consumption. Petroleum products include gasoline, diesel fuel and heating oil, liquefied petroleum gas, jet fuel, still gas, asphalt and road oil, naptha for feedstock, lubricants, kerosene waxes and many more. Oil has served its purpose for many decades but has become unsustainable. The world reserves are said to be declining and global warming is also said to have been caused in part from its excessive consumption.

Renewable sources of energy have gained large popularity in recent years as a way to free

ourselves from oil consumption. Renewable sources of energy include solar energy, wing energy, geothermal energy, biomass or bioenergy and hydropower amongst others. The problem encountered with many of these types of energy is that they are not financially viable at the moment. Even though oil is harmful to the environment since it is still more economical than renewable sources then it is still consumed.

In conclusion energy is all around us, from the airplane in which you travel to the light bulb that light up your house. Even when energy cannot be destroyed we still have to cherish the energy sources available to us and also cherish the place it came from (earth). It is in the hands of engineers and scientists to find new and exciting ways in which energy can be used more efficiently and environmentally friendly which will be a very important challenge during our lifetime.

References:

Fundamentals of Engineering Thermodynamics, Michael Moran, 5th edition

Fundamentals of Physics, Halliday, 7th edition

http://library.thinkquest.org/2745/data/lawce1.htm

http://www.youtube.com/watch?v=o_5oYuDY2qM

http://www.energyquest.ca.gov/story/

http://www.eia.gov/energyexplained/index.cfm?page=oil_use

What are electromagnetic waves and how they work are in microwaves, x-rays,

and similar objects

Richard Rosa Figueroa

In our daily lives we use many types of electromagnetic waves, some of which we don’t know we use. For example, most people use microwaves daily, others use x-rays and radio waves. Electromagnetic waves are formed when an electric field couples with a magnetic field. The magnetic and electric fields of an electromagnetic wave are perpendicular to each other and to the direction of the wave. Unlike other waves, the energy streams caused by the interaction of magnetic and electrical forces can travel through empty space. Electromagnetic streams have peaks and troughs, caused by the forces push and pull of one another. The wavelengths are discovered by measuring the distance between two identical points of the waves from cycle to cycle. For example, the distance between one crest and the next is the wavelength. Electromagnetic waves are classified according to wavelengths and energy. Higher energy waves have short wavelengths and lower energy waves have a long wavelengths. The scale that describes the different types of waves is called the electromagnetic spectrum. In this scale we can see that radio waves are found at the bottom of the scale, while visible light sits in the middle and gamma rays at the top of the scale.

A microwave oven works by passing non-ionizing microwave radiation through the food. Microwave radiation is between common radio and infrared frequencies. Microwaves are used to cook food faster than a stove or an oven. A radio wave is composed of electromagnetic radiation. The radio transmitter sends out radio waves at a specific frequency or band of frequencies and the aerial receiver develops tiny electric currents in it as the radio wave flows past it. These are pulsing currents at the same frequency of the radio wave. This content or signal is carried in the wave and this is the concept of the carrier wave. X-rays are electromagnetic radiation carried by photons. Like the visible light spectrum, another portion of the electromagnetic scale, x-rays may either pass through, be absorbed by or reflect off a material based on its subatomic structure. The difference between x-rays and visible light is that x-rays exist farther up on the electromagnetic scale and that’s why they have a smaller wavelength and higher energy level. X-rays are used by doctors for the diagnosis and analysis of broken bones, tooth structure, and the presence of cancer, gaps, lumps or other problems in soft tissue. Using captured images, doctors can diagnose and treat simple fractures, fractures that don't break the skin and hide structural defects within teeth.

As technology advances maybe so will the use of electromagnetic waves, they could be used for more things that could help humans in their daily lives. For example, today’s televisions, they all work with LCD and plasma technology and both of them emit electromagnetic waves. Same with the cell phones, they also emit electromagnetic waves. Both of these objects are constantly being modified and made with better uses, this is the same case with many other electrical objects.

Lens, magnification, optics, and a little of holographic imaging

Michael A Casciano Kotick

Starting the lectures of Physics II, nothing caught my attention more than the interesting facts about lens, and how in-depth it can be. Lens is a transparent material that is bordered with two bending planes. It will refract the light that comes from an object (Light behind an object) and makes virtual or real images of objects. Lens has two basic types, which are convex lens and concave lens. Convex lens has the thinnest part in its side, while concave lens has thinnest part in its center. The parts of a convex lens are the focus point which are principal and virtual, also principal axis, lens curvature, and optical center. Convex lens has three different shapes called: biconvex, plan-convex, and concave-convex. Although there are 3 shape of convex lens, the main system and characteristic is the same. The properties of these are collect ray which is convergent, has a positive focus value and has two focuses being principal and virtual. Particular to the ray of convex is the fact it is a ray parallel to the principal axis which is refracted through the principal focus. Also, a ray through a virtual focus is refracted parallel to the principal axis. And finally, it is a ray through the optical center that is not refracted.

Continuing, one notices the second lens called the concave lens. It is described to have the thinnest part in its center. Similar to the convex, the concave lens has three types of shapes: biconcave, plan-concave, and convex-concave. Although there are 3 shape of concave lens, the main system and characteristic is same. The concave lens has different properties being the spread ray making it divergent; it has a negative focus value, and has two focus, virtual and principal focus. Its parts consist of the optical center, focus point, principal axis and lens curvature. The particular ray is parallel to principal axis is refracted like from active focus point, F1,  yet toward F2 is refracted parallel to principal axis and finally, can be a ray through the optical center not refracted. Images on a concave lens are always makes virtual, upright, and minimized image.

The function of lens is to make optical object, like magnifying glass, eyeglasses, microscope, and others. In lens, there is also relationship between focus distance, object distance, and image distance. The formula is same with mirror:

do = Object distance to lens (m)

di = Image distance to lens (m)

f = Focus distance (m)

Beside focus, object distance, and image distance, we can calculate magnification and height of object and image.

M= Magnification

hi= Height of image

ho= Height of object

do= Object distance to lens

di= Image distance to lens 

Continuing the readings one comes across the power of lens, besides magnification and focus. Power of lens is more often used than the other. Example, you can sometimes hear in everyday life about his glasses are -1, -2, and -5. The equation has P=magnification, and f=focus distance.

The next topic is optics which is the study of the behaviour and properties of light including its interactions with matter and its detection by instruments. Optics usually describes the behaviour of visible, infrared, and ultraviolet light; however because light is an electromagnetic wave, similar phenomena occur in X-rays, microwaves, radio waves, and other forms of electromagnetic radiation and analogous phenomena occur with charged particle beams. Since the discovery by James Clerk Maxwell that light is electromagnetic radiation, optics has largely been regarded in theoretical physics as a sub-field of electromagnetism. In set theory, a branch of mathematics, a reflection principle says that it is possible to find sets that resemble the class of all sets. There are several different forms of the reflection principle depending on exactly what is meant by "resemble". In mathematics, a reflection formula or reflection relation for a function f is a relationship between f (a-x) and f(x). It is a special case of a functional equation, and it is very common in the literature to refer to use the term "functional equation" when "reflection formula" is meant. Reflection formulas are useful for numerical computation of special functions. In effect, an approximation that has greater accuracy or only converges on one side of a reflection point (typically in the positive half of the complex plane) can be employed for all arguments. The even and odd functions satisfy simple reflection relations around a=0. For all even functions,

Finally, ending with a topic that is not studied in the Physics II class but after looking up more intense information on lens, optics, and magnification, I came across the theory of holographic imaging is formulated in terms familiar from conventional optics. The effects of the curvatures and off-axis angles of the reference and read-out waves are described by equivalent thin lenses and prisms. The formation of the true-image wave field is found to be completely analogous to the conventional imaging of the object wave field by the equivalent lenses and prisms. To explain the conjugate image, we introduce the concept of time reversal. The conjugate-image wave field is the time-reversed object wave field conventionally imaged by equivalent lenses and prisms (and a plane mirror). The finite size and resolution of the photographic plate are taken into account. The size of the plate determines the effective aperture of the equivalent lenses and prisms; it is equivalent to a diaphragm in the hologram plane. The modulation transfer function of the plate has the same effect as a diaphragm inserted in the imaging bundle during the recording (or the reconstruction) with its center at the reference (read-out) point. The two diaphragms limit the field of view and the resolution. In the end, this is just a small taste of information starting from Physics II class to a more advance. Hopefully as an engineer student, I will be able to learn more about optics, lens and holographic imaging.

Friction in our life


Sean C Crespo Gomez

With just a few introductory lectures about friction, we can see friction’s importance in our daily life. It is important to have knowledge about what is friction and how it affects us, if we have enough knowledge about friction, it can be used as an advantage in life. We can find many simple examples related to friction, as: the slippery floor when it’s wet, the oil needed to lubricate the engine and allow its parts to move easily, and when some surface is polished to shine and it does not feel rough. In some cases we need to move something heavy and we can realize that it’s much easier to roll it or somehow avoid friction between the object and the floor. That is why we need to know when we need friction in our favor, or if somehow we have to deal with the forces. We must first know the pros and cons of friction. It’s easy to note that excess friction can make it difficult to slide a box across the floor, ride a bicycle or walk through sand. We can also relate friction with the consumption of gasoline. If we deal with friction from our vehicle taking simple measures such as keeping the right amount of tire pressure, and avoiding excessive loads on the car we will see gasoline consumption remains constant and reasonable.   

    

Basically, we can define friction as the force developed between a moving body and the surface being in contact with it. An example is when you apply the brakes of a car, it’s instant friction between tires and pavement. Friction is a force that is opposite to the motion of a body on which he works. Friction is usually classified as Static friction and Dynamic (kinetic) friction. Static friction is a force which resists the lateral movement of two objects which are touching each other. In other words, static friction prevents an object to move and is equal to the net force applied to the body, but with opposite direction because it prevents the movement. When objects have a high friction coefficient it means that a large amount of force is required to break the force of static friction and create movement, while a low coefficient means that less force will be exerted. On the other hand, we have the dynamic friction (kinetic). This is when movement is involved. It’s the friction generated between two dry surfaces in contact during movement. The product is a kinetic friction coefficient of kinetic friction force and normal reaction. It assumes a constant value regardless of the amount of applied force or speed of movement. Its value is always less than the limiting friction between the same two surfaces. 

In my opinion, friction is one of the most fundamental topics in Physics due to the fact that almost every other topic is related to it. Trough this essay, I’m implying that we don’t need to be an expert on this subject, although it would be amazingly useful to cope with our daily life.

Neutrinos and the Speed of Light

Adria D. Venialgo Báez

In Physics II we have been talking about light. We know that light can behave sometimes as a particle and sometimes as a wave. We also know that the speed of light can be determined both in vacuum as when it is traveling through another medium, like glass or another materials. Since Albert Einstein has establish his theory of relativity in 1905 with his famous equation E=mc², it has been determined that there is no particle in the Universe that can travel faster than light does. But recently scientists have been talking about some kind of particle which can change the history of physics and indeed, we may be witnesses of a very transcendental moment in history related to these theories of relativity.

On September 15, 2011 the scientific leader of the project OPERA of the Large Hadron Collider, Antonio Ereditato, gave the results of an experiment that he and a very large team of other scientists have been doing. These results were so stunning that they had to do it 15,000 times giving always the same number; a particle known as neutrino can travel 60 nanoseconds faster than light.  To know more about neutrinos, they are a kind of subatomic particle without charge with ½ spin. It has mass but very small and hard do measure. It is said that it weighs less than 5.5 eV/c². Its interaction with other particles is too small so they travel through matter without disturbing it. The existence of the neutrino was on 1930 by the physicist Wolfgang Pauli and on 1956 the physicists Clyde Cowan and Frederick Reines has demonstrated by experiment. With the “neutrino experiment” a beam of 1018 neutrons was bombarding pure water. It have been made experiments to determine the velocity at which they travel and they made an important discovery that would put into question the veracity of the theories of relativity proposed by Albert Einstein in 1905. After repeat the same experiment over 15,000 times it has been found that neutrinos travel 60 nanoseconds faster than light.

Only this project OPERA have been doing this experiment so they announced their findings and proposed to another scientists around the world to make the same experiment to confirm the results because if there right, it will be an important advancement in the area of physics. We will probably been facing the born of new questions about relativity and theories than could explain this new phenomena. Physicists will have to explain why these kind of particles can travel faster than light and how they do it, how is that they were not been discovered until now and if there are other particles in the world than could have this same behavior. They have to investigate if there is a connection between neutrinos, black matter, the origin of the Universe and the actual laws of Physics or if there has to be more information that we do not know yet to explain the world in where we are living. Maybe we are about to begin a new era of physics in which scientist will discover more about our cosmos, about time and space. 

How Do Telescopes Work?

Wigberto L Maldonado Rodriguez

It is more often thought that telescopes are meant for the purpose of magnification in the night sky. While this is not always true, the important fact remains that telescopes are used for the purpose of accumulating light to enable scientists and astronomers to view faint objects with ease.

The main idea behind the telescope is that, it works by focusing the incoming light to the development of an image. This image is best viewed by means of an eye piece, which in turn acts as the magnifying glass. The opening through which light enters is referred to as the aperture and the presence of a larger aperture implies that light is gathered more. The light that enters is collected and is passed through a lens that is at the opening of the tube. This tends to bend the light together as a whole. From there, it is brought to a single point, termed as the focus that is exclusively designed to occur at the end of the wide tube, referred to the body. The eye piece actually remains slotted at the end of the telescope and features a slide in mechanism that helps to adjust the focus depending on the needs of the user. There are many other varieties of telescopes however the refractor design is the simplest and the one most commonly in use.

Reflectors were initially developed in the year 1680, the Reflectors are devices that are the result in correcting the chromatic aberrations that were developed. It employed the usage of a little curved mirror instead of a lens to gather the light and point it out to a focus. A modified version of the Reflector was developed in the year 1722 that featured parabolic mirrors and there were changes to the mirrors that were used. The Newtonian model is one of the most successful models of the telescope. Dobsonian reflector telescope is a type of the Newtonian model and is featured with a simple tube and have apertures ranging from six to 17 inches. They are more economical; however, the one disadvantage with a reflector telescope is to align the mirrors often.

Refractors were invented by Hans Lippershey and used by Galileo, the Refractors are a combination of concave and convex lenses. They essentially comprise three distinct parts and thus, employ the usage of lenses that do not correct achromatic aberrations to the max. To overcome this issue, these telescopes are features with lenses or that are “coated” or lenses that are made of fluorite glass to overcome the problem. Refractor telescopes feature good resolution that is ideal to see distant sky objects such as the planets and stars with ease. Their objective lenses are more than 4 inches in diameter and they are the costlier than the Reflector type on account of the lenses used. The basic principle behind these Refractors is the refraction of light, where light travels from a rarer medium towards a much denser medium and is represented by Snell’s Law; μ=Sini /Sinr Snell’s Law, the most common law that is used to describe the angles of refraction and incidence is also applied in a Refractor to explain the concept of chromatic aberrations caused due to dispersion. However, with the development of achromatic lenses, this phenomenon has reduced to a greater extent. There are many factors that are associated with the working of telescope such as the Aperture, the magnification, focal length and more.

Aperture refers to the most important section when buying a telescope. A telescope with a larger aperture implies that it can view objects that are faint with ease, unlike a telescope with a smaller aperture. It is measured in terms of mm in diameter and thus a telescope with a minimum of 120 mm aperture tends to gather as much as four times the quantity of light that enters through it. It is also referred to as the primary mirror aperture or that of the objective lens. The highest magnification that is used in the aperture is the theoretical limit and should not exceed more than that is required. When magnified too much, objects tend to move out of detail and thus clarity is lost. It is known that for every 1 mm of aperture opening, there is a magnification of two times. This is also referred to as the highest Practical power of the telescope. Focal length is the distance at which the telescope focuses on an image. There are eyepieces that tend to have varying focal lengths and thus it is a combination of the telescope focal length and the eye piece focal length that tends to deliver the possible magnification. There are eye pieces that come in varied focal lengths varying from 50 mm to 2mm and usage of multiple eye pieces will help to deliver magnifications at different lengths.

Antimatter and the Large Hadron Collider

Adriana Noemi Santiago Miranda 

During the course of high school and during my first years of college, I remembered being told that the atomic model was composed by electrons, neutrons and protons, and therefore I assumed that besides these particles and the photons, there were no other subatomic particles. For my surprise, just a few months ago, I discovered that this was not true. The discovery of the first subatomic particle, the electron, was achieved by in 1897 by J. J. Thomson. Then in 1905, Albert Einstein demonstrated the physical reality of the photons, hypothesized by Max Planck in 1900, in order to solve the problem of black body radiation. The proton was discovered in 1918 and the neutron in 1932. That same year the first antiparticle, the positron, was discovered by Carl D. Anderson. To the date 25 different kind of subatomic particles had been discovered: six types of quarks, six types of leptons and thirteen gauge bosons. 

Antiparticles or antimatter are the corresponding part of usual particles; they have the same mass but opposite charge. Curiously an antiproton and a positron can make an antihydrogen atom which has similar properties than a regular hydrogen atom. From this fact raises the question of why the universe is conformed primarily by matter instead of half antimatter and half matter. The CP violation, a postulate of particle physics, tries to explain the dominancy of matter over antimatter and why such symmetry doesn’t exist. Nevertheless, this is one of the most controversial unanswered questions of the physics world. 

When matter collides with antimatter annihilation occurs. In this process the two particles collide to create new particles, for example, during low energy annihilation photons are created. Particle accelerators use colliding positrons (antielectrons) and electros at relativistic speeds to create annihilation that by consequence, create diverse subatomic particles. Physicists study the results of these collisions to test theoretical predictions and to search for new kinds of subatomic particles. Specifically, the Large Hadron Collider was created to address some of the most fundamental questions of physics and laws of nature.

It has a circumference of 16.8 miles and is 328 feet underground and use 9,600 magnets that are cooled to 1.9 degrees Kelvin, very close to the absolute temperature. It uses magnets of several tons that propel particles at 99.99% the speed of light! Some of the main questions that are hope to be answered using this equipment are: the existence of extra dimensions as predicted by models based on the String Theory, the nature of dark matter and why are there apparent violations of the symmetry between matter and antimatter. In September 2011 the Large Hadron Collider claimed to have measured neutrinos faster than the speed of light, putting Einstein's theory into question. A huge controversy raised but then, this was proved false when it was found that the departure time was miscalculated.

Without Gravity Force

Glorimar Torres Pagan

Imagine walking through a park, all appears to be a quiet environment, a warm breeze, and the leaves of the trees moving by the wind, others falling down onto the ground, the birds singing and the children playing throwing the ball. We decided to sit on a bench, which is just below an orange tree, and suddenly "boom", an orange falling over our head. We got up from the bench and wonder ourselves how it may have fallen on me this orange, having a lot of space around me? It is then, where Isaac Newton leaves us the legacy of the law of gravity, where what goes up must come down because gravity is a phenomenon by which all objects with a given mass attract each other.

But what if there is no such force? If gravity did not exist then, neither exist the force of attraction of the masses, so that would not exist our planet. Earth would be a core of rock with a tendency to disintegrate; it would be like a rock floating in a vacuum. The atmosphere would not be there, so there would be no oxygen to breathe. The water would not be forming seas; there would be no plants, no life. In addition to considering the tectonic plates, would have plates being created and destroyed on the surface, generating the grit that tend to flew off the planet. If it would impact a meteorite, it will produce the total evaporation of the planet, or it will accelerate the existing one. Without gravity the final result would be the disappearance of any celestial body that could be formed.

Now, suppose that our scientific development has reached a level where we can breathe oxygen artificially. Still we would have physical changes, our muscles would be weak, and we would be taller and thinner. Similarly, the plants would be enormous and elongated. From the worldly point of view, we would be floating weightless. The universe would be only dust and gas, as gravity was the driving force that joined these masses to form stars. This dust and gas would be dispersed within the limits of the universe, forming a sort of vacuum oval inside and all the mass around it. The universe would be infinite because there would be force to halt the expansion. Moreover, since gravity is a manifestation of the curvature of space, in those areas of the universe, curvature would not exist thereby causing the time be the same anywhere in the universe.

Returning again to imagine us in the park, this time without the presence of gravity, we would be able to float from one location to another; the warm breeze would in this case, threatening, since it can raise an undetermined height. The leaves of the trees would be floating along with the trunk, being a dangerous object. The singing of birds is infinitely dispersed and children lose the ball after they thrown it. Finally, when we can sit on the bench, the orange are not going to fall on our head.

Doppler Effect Applications

Glenda Enid Diaz Acosta

For a given source of a wave and an observer in a fixed distance from this source, the wave emitted from the source will arrive at the observer crest after crest, and there would be a fixed period of the wave; that is the time it takes for one complete cycle of the wave to occur, this period(T) is used to calculate the frequency of the wave given that the period of a wave equals one over the frequency of the same wave(which is also equal to the wavelength of the wave divided by the velocity of sound), and the frequency obtained of the wave will be observed to be the same as the frequency of the wave generated by the source. If then both the source and the observer are in motion relative to each other, then The Doppler Effect takes place. The Doppler Effect is the apparent change in the frequency of a wave, occurring when the source and observer are in motion relative to each other, with the frequency increasing when the source and observer approach each other and decreasing when they move apart from each other. It we have a certain time (T) given we have an apparent change in frequency (f')  of the wave in because of this effect, where f^'=f(1±v_source/v_snd ), in which the v_source is the velocity of the source, v_snd is the velocity of sound in the medium, and f is the frequency of the emitted wave. If we know the frequency of the wave send by the source and the velocity of that source then we can apply this equation and find out the apparent change in frequency, which will allow us to calculate the distance between the source and the observer.

The Doppler Effect has many practical applications for example astronomers use Doppler shifts to calculate precisely how fast stars and other astronomical objects move toward or away from Earth, physicians apply it to measure the rate and direction of blood flow in a patient's body, and also this is the principle used in radar and sonar work; by measuring changes in wavelength and frequency sonar and radar can be used to detect unseen objects and their distance from the observer. Sonar is used to locate under water objects, a transmitter sends out a pulse through the water, and a detector receives its reflection, the time interval between when the pulse is send and received is measured and by applying the Doppler Effect the distance to the reflecting object can be determine using as v_snd  the speed of sound in water. This is used the military to look for submarines and by ocean scientists to find out the depth of water and to map the contours of the ocean bottom, by oceanographers to study everything from the ocean bottom to the waves on top. 

The concept of the Doppler Effect has helped to expand our knowledge of waves. This has helped scientist to hypothesize on the formation of the universe and important theories in physics such as the theory of relativity. It is the basics for the development of the acoustic Doppler velocimeter (ADV) which was develop to measure the velocities in which a fluid flows. In addition it has helped to develop ultrasound machines and  weather radars which use Doppler pulse for meteorological applications, and  also to develop Doppler radars which are used in artifacts as complex as airplanes, and in artifacts as common as police speed guns used to determine the speed of passing vehicles in a common day basics. 

Light and How It Relates To Physics

Yamil Einar Asusta Santos

Light is a transverse, electromagnetic wave that can be seen by the human eye. Light is generally described by the measure of its wavelength in a vacuum. Light’s speed is also measured in a vacuum. Speed of light is measured in units of c, which is derived from the Latin, celeritas, which means swiftness. Colors of light are directly related to the light’s frequency. There are two main groups of light frequency colors.

The wavelength of light can be found by a formula that is inversely proportional to its frequency.  Although frequency is generally associated with light, frequency is the measure used for any wave phenomena. Possible wavelengths of late range from 400nm of violet light, and 700nm of red light. Polarization is a technique used to prove that light is transverse. During the early stages of study of light, light waves were first illustrated by experiments of interference and diffraction.

Light speed is a term used by many without even knowing how incredibly fast light travels. In a vacuum, light speed has been determined at a speed of 299,792,458 meters per second. It is important to note that the speed of light will always be slower in any medium, than it is in the vacuum. “In fact I have tried the experiment only at a short distance, less than a mile, from which I have not been able to ascertain with certainty whether the appearance of the opposite light was instantaneous or not; but if not instantaneous it is extraordinarily rapid.” (Galileo Galilei) Through modern technology and mathematics, science has taken great steps from trying to measure light by watching with a naked eye, turning on a lamp from a mile away, to simply plugging distance, time, wavelengths, frequency and type of light into an equation.

Although many have generalized light into six simple colors: orange, yellow, red, green, blue, and violet, there are in fact many types of light color. There are two major types of color of light. Monochromatic light can be described by simply one frequency while polychromatic light is described by several frequencies. Laser light, and the six simple colors are each monochromatic types of light specific to their own frequency. There are many more polychromatic light sources than there are monochromatic. An example of polychromatic light is white light. Light can also be non-visible, such as infrared light and ultraviolet light.

Since the early Greeks, the world’s population has been fascinated by light and it’s value to human life. Before modern science, it was not known whether light traveled at a finite speed, or if it was instantaneous. This was a hotly debated question until Rømer proved the finite speed of light. Before him, the first person to declare that light traveled at a finite speed was Empedocles. Even Aristotle did not believe him and said, "light is due to the presence of something, but it is not a movement". Light will continue to fascinate scientists all around the world, while they try to harness it’s power for improved energy efficiency and medial uses.

How does a Television work regards to physics (electromagnetic wave, image rendering, cathode ray tube, etc.)

Eduardo Miguel Breijo Baullosa

In today’s advanced and developed world, television plays a vital role for the efficient and effective development in the field of communication it. Not only this, it has also become the part of entertainment in our life. At present context, we are fond of it but the saddest thing is that, most of us even don’t know how it works. We are only concerned to use it but we are never concerned to know about it practically. That is the main problem within us of being in a back position. Anyways, we all of us must know what Television is so that we must not sit quiet when someone question us about it.

Actually, television is a telecommunication medium for transmitting and receiving moving images that can be monochrome i.e. black and white, or colored or without accompanying sound which produces a series of tiny dots on screen that appears as an image when it is seen as whole. Most of the kinds of television work from the basic principle. A tube-type color television has three colored light guns behind the screen which are red, green and blue where strong magnets sweep the single beams back and forth across the horizontal rows from top to bottom in a lawn mowing pattern which is repeated 60 times every second to create the illusion of a solid moving picture. And, then the three colors get mixed to create any color on a tiny dot of lights on the TV screen called pixels which flashes according to a specific pattern provided by the video signal. A person’s eyes transmit this pattern to the brain, where it is interpreted as a recognizable image. The refreshing speed of patterns by television is hundreds of times per second that is faster than the view of human eye which gives the illusion of movement.

In older days, televisions rely on Cathode Ray Tube to produce images and operate analog signal which are commonly called CRT televisions. These television uses an evacuated glass envelope which is large, long from face screen to rear end and is quite heavy whose main work is to deflect and accelerate the electron beam onto the fluorescent screen to create fine images and it is the main reason which helps in rendering images in the television by emitting the light which is not visible to naked eye.                               

An analog television works by transferring electromagnetic waves into sound and light energy where TV box works like any receiver which takes electrical impulses in, sent from elsewhere and changes those bits of information into something which can be seen and heard by the people. Color televisions are created by mixing several beams of light which primarily works by regulating red, blue and green light in different patterns against called “phosphor sheet”. All the TVs have these sheets placed behind the glass portion of it. The difference is only that Black and White televisions have only one sheet whereas color televisions have three phosphor sheets which help for television to work instantly.

Nowadays, as technology has advanced and broadcast signals, discovery from analog to digital, plasma and LCD (Liquid Crystal Display) are developed which have more compact and have crisper images than their cathode ray counterparts because they use thin grid of pixels to create images rather than a vacuum tube. We all are waiting for further development of different kind of televisions in order to be facilitated and entertained by various ways.

Possible worlds, a new frontier

Edgardo E Estavillo Torrellas

Our daily life is based on decisions, every decision have an effect, imagine every possible path one could follow result in the creation of another reality. This argument was first expose in the 50’s by the American physicists Hugh Everett with his proposal of the “Many-Worlds Interpretation,” theory supported by the quantum physics. The physics and also philosophical hypotheses break the precedent perspective of reality as a single unfolding history. The MWI theory states that in every point when there is a possibility regarding to an event the universe divides as branches in a tree. If this statement is true this means there is an infinite number of universes, since every possibility exist.

In terms of quantum theory this hypothesis phenomena could be better explain by the Schrödinger's cat paradox. This thought experiment was first executed by the Austrian physicist Erwin Schrödinger in 1935. The test puts a cat under a dangerous situation in which the survivor of the animal will be determine by an earlier random event. The result of this experiment is supported by the Copenhagen interpretation of quantum mechanics, which predicts a dualistic path for the cat after the event, been simultaneously alive and dead. 

The latest contribution to this powerful and intriguing new perspective of the universe was made by the physicist and cosmologist Alan Guth. This professor of Physics at the Massachusetts Institute of Technology gave a new turn to the (MWI) in a scientific sense, by delivering to the world the inflationary universe theory. This new hypothesis tells that at the beginning of the universe there was a kind of reverse gravitational pull, which instead keeping things together, it repelled everything, this is what Guth call “false vacuum.” Guth states in his theory that when the big bang occur, this false vacuum effect began to decay and that in this process a great amount of particles were created; the same kind of particles which mark the beginning of our universe. These particles became like bubbles which the physicist believe gave birth to our universe. The tendency expose by Guth states that the more the false vacuum effect decayed the more bubbles were created. This theory will explain the existence of many universes, all apparently compose by the same properties and also build within the same laws of physics. If this theory is true the idea of the size of the universe that science community have, would dramatically increase in a way that nobody in history has thought of. Sense at this time there is no available technology that could prove this theory there still and open space for speculation of what these other universes might hold. 

At the moment any suggestion of what might be found in these other universes remains in the philosophical side. Finally, another issue here is that if we hold the universe is infinite this doesn’t necessarily mean that there exist infinite forms of arrangement in particles. So analytically, if in an infinite universe there exists define or finite array of forms in particles this theory would make a lot of sense.