WHAT IS ENERGY EXACTLY?

“If you want to find the secrets of the universe, think in terms of energy, frequency and vibration.”

-Nikola Tesla

We need energy to do our daily life works like walking, weight lifting, dancing, etc., In physics energy is termed as the ability to do work. You can’t see energy because, it’s not a physical thing, rather it is a property of a thing. This property helps to do work on an object. The definition of the energy explains what it can do, but we don’t know what it is?

Energy is classified into many types, such as Kinetic energy, Potential energy, Chemical energy, Thermal energy, Nuclear energy and so on. If we look closer into it, we shall find that all other energies are merely kinetic and potential energy in microscopic scale. For example, Chemical energy is just a potential energy due to chemical bonds and thermal energy is just a kinetic energy due to the motion of the particles. So, energy is generally classified into two things, one is Kinetic energy, which contributes the motion of the particles and the other one is potential energy which contributes the potentiality of an object to do a work. 

Leibniz (1646-1716) noticed that the quantity ∑mv² was conserved in many collisions. He called it as “Vis Viva” or “Living forces”. It was later known as the conservation of kinetic energy. Consider an object moving in a constant velocity and an external force be applied to it. A work must be done on that object by the force to accelerate it. After the work is done, the object acquires a new velocity. From this example, we shall notice that, the object has gained something by the work done by the force. That ‘something’ is called as the kinetic energy. It is proportional to the velocity of the object and it can be transformed into thermal or sound energy.

Potential energy or latent energy answers to the question, how much the object is potential to perform a work? For example, imagine you are preparing for your physics test and you have only covered half of the syllabus. Which means you are only half ‘potential’ and ‘able’ to answer half of the questions. If you have covered full syllabus then, you are fully ‘potential’ and ‘able’ to answer full questions. Potential energy is a stored energy which can be transformed into kinetic energy to perform a work. In case of gravitational potential, the energy stored is proportional to the height from the ground and in case of chemical energy, the energy stored is proportional to the binding force of the chemical bonds of the materials.

The universe is still functioning because of its dynamic properties. From electron revolving around the nucleus to the explosion of the supernovae, energy plays a crucial role in different forms. Energy gives a behavior to the matter. According to the special relativity theory, Energy and Mass are the different manifestations of a same thing. So, change in energy level also affects the mass of a matter. Thus, energy is a number which indicates the change in state or motion of a matter.