Prime Solar Company

“Energy can neither be created nor destroyed.” This is the first law of thermodynamics. What this means is that the amount of energy you can get out of something cannot be more than is put in. Work is defined as the amount of energy that it takes to raise an object to a certain height or temperature; i.e., potential energy. The amount of work you get out of a system cannot be more than you put in.

Heat can be changed into motion, and motion can be changed into heat. You can also exchange weight for distance – mechanical advantage. Let’s assume you have a two-pound weight at one end of a lever on the ground, and a one-pound weight at the other end of the lever in the air. The two-pound weight will be lifted when the length of the lever is more than twice as long on the one-pound side. The two pound weight now has more “potential energy”. And the one pound weight has less. But the total potential of the whole system has not changed. (In reality friction in the bearing and air will a very small amount of “potential energy” from the system. But that is a whole other discussion.)

Motion can be changed into heat. A simple example is rubbing your hands together. You can change heat into motion by putting water on the stove to boil. The cover on the pot will jump around as the steam escapes.

There are many other form of potential energy we use every day. Electrical charge is one of them. Heat potential is another. A spinning wheel another. If one object is warmer than another; i.e., a piece of steel in the sun is warmer than the surrounding air than work can be done with that difference. Another is chemical energy or burning. The “potential energy” of the gas being used by a stove is greater than the by-products of the combustion. A gas under pressure in a spray can is another example of potential energy. And if you were to heat that can, the “energy potential” would increase until the can ruptured. And created a mess!

All substances can be looked at in terms of their potential energy. And every one of them has “potential energy” in many of the ways described above. A piece of wood has chemical potential in that it can be burned (a release of energy), and may have “potential energy” in the it can fall (lifting something else). The piece of wood may also be warmer than the surrounding area, creating a heat potential. We, as human animals, take the energy of our food, and convert it into work. So in order for us to get work done, we use something with a higher “potential energy” to raise the “potential energy” of something else.