What's the big deal about potential energy?

Patty B. asks, "Dr. Volt, what's the big deal about potential energy?"

Ah, potential energy, one of my favorite concepts, for really, where would we be without it? But let's start at the beginning with energy in general. There are two primary types of energy: kinetic energy and potential energy. An object's total energy is the sum of the two and will always remain constant.^** Kinetic energy is an object's energy of motion, given by Kinetic Energy = ½mv². Here m is the object's mass and v is the object's velocity (or speed). All other forms of energy are potential energy, which simply means that they have the potential to become energy of motion. Gravitational potential energy would be a common example. As a lift an object up (that is, away from the Earth) it gains potential energy due to gravity. When I release the object, and gravity pulls it back to Earth, that potential energy is transformed into kinetic energy.

But perhaps a more mad sciencey example is in order. Another form of potential energy is chemical potential energy, which is how batteries work. In a battery a chemical reaction inside creates an electric current, which is simply electrons in motion, i.e. kinetic energy. But a much more exciting example is this:

That's right, it's our old friend trinitrotoluene, better known as TNT. TNT is a chemical that contains a great deal of chemical potential energy, enough so that when that potential energy is released the results are quite, well, explosive. Chemical potential energy is also found in many fuels that we use, such as oil or coal, not to mention the food we eat in order to gain the energy to pursue our dreams of world domination (I am quite partial in this regard to banana splits). So you see, Patty, potential energy is all around us and is quite a big deal indeed! For more information on potential energy I suggest you attend my Mad Scientist Training Academy this summer (Assistant's note: see Schrödinger's Cat Must Die!). I think you shall find it most enlightening! **All right, technically it is the mass and energy combined that remains constant, as shown by Einstein in his famous equation Energy = mc2 where c is the speed of light. Show off.