How Does Energy Change From One Form to Another?

Energy changes from one form to another by interacting with objects in its environment that resist the influence of that energy. Like electricity traveling through a superconductor, not all interactions actually result in an energy transformation. Only those interactions in which the objects resist the energy in some way result in energy transformations, and that resistance is literally the transformation of that energy.

Except in a very few circumstances, such as in a superconductor, all energetic interactions produce some sort of resistance. Air is slightly resistant to the passage of light as well as the motion of objects in it. Only a few materials under very specific conditions do not offer some resistance to electrical currents. In all such cases, this property is called resistance, since these objects and substances mean that more energy must be emitted at one location than energy of the same type is received any distance away from the source. The amount of decrease is equivalent to the resistance of the object or substance.

An excellent example is an incandescent light bulb, which works via electrical resistance. The current travelling through the wires to the bulb experiences only minimal resistance and little energy transformation. However, the filament is much thinner and has much less space for electrons to travel through, and the excess electrical energy does not disappear. Instead of moving electrons, their energy excites the atoms of the filament itself, causing them to heat up and emit light.