As human beings we like to know the world around us. As we grow up we realize that most of the nature, objects, and events around us have a reason to be. We learn the reason for the rain, the storms, the twisters. We find out that in the moon a person can float, the mass is the same, but the weight changes from the one you have on planet Earth, and that is due to the difference of gravity between the Earth and the Moon. An event that is quite interesting is the fact that a person can weight much less submerged in water. It may be an event we do not understand, but it truly is fascinating.
How come a seven year old little girl could carry her nineteen year old sister submerged in water when on the ground the little girl can barely even make her sister move a few steps? It is not an easy job to explain the little girl why this happens, but she sure enjoys it. She can carry her sister all around the water and for her that is quite fun. She does not understand it. Eventually she will learn about science. She will learn that everything around us has an explanation. The classes may serve to help her grow in mind. She learns about the water cycle and how the water transforms in the different states. The mass is not created or destructed, it transforms. She learns about the properties of the earth, the way her body works and how it changes, she learns she must make certain force just to be moving all the time, and when it comes to moving something else, even more force must be applied. All this learning leads to more questions. It feeds the hunger to learn, to understand and to appreciate the events around her. But there is never enough knowledge, we keep learning until the day we day. Answers are given and more question rise in our minds until eventually the girl wonders why can I person weight much less submerged under water than on the ground.
That question leads to physics. The answer to that doubt is all in the forces that are applied to a body when it is submerged in a liquid, which in this case we consider is water. It is of common knowledge that gravity is force on every single object on Earth at any moment. This means even when a person or an object is submerged in water will still have the force of gravity upon it. That rule does not change. The only way that force can be canceled, or at least lessen its amount is by having another force facing the opposite direction from the force of gravity. This lead to having them against each other. Since, just like in the moon, our weight changes with gravity, we can assume that the force done from the water, upwards and towards the surface, must be bigger than the force of gravity applied. Since the water force is pushing upwards, this makes it easier to lift a person submerged in water.
In conclusion, science can explain the events around us. Little by little we learn the reasons why. When it comes to all the object on earth, they all have a force of gravity acting upon them. The weight changes when the gravity does. Which means that if there is a certain force acting against the gravity, and this force is bigger, the weight of the object or person will be affected, lessening it. This is the reason why it could be easy for a seven year old girl to carry her nineteen year old sister, as long as they are submerged in water.
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