| MadSci Network: Physics |
First, I should explain what energy is: energy is work, or the ability to do work.
Here, work means pushing or pulling something some distance.
Electric energy is doing work by moving electric charges - usually electrons - through a conductor, usually wire made of metal.
Energy cannot be created from nothingness, and it cannot be destroyed. However, energy can be changed from one type of energy to another. One of those types of energy is electric energy, electricity.
Electricity can do work because electrons are being pushed some distance through a wire by an "electromotive force" that we measure as the voltage. We pay for the amount of energy we use in our homes, paying a certain cost for each kilowatt-hour or electric energy we use.
Kilowatt hours are obtained by multipling how fast electrons are moving (the current, in amperes), times the electromotive force (in volts) to obtain watts, then times the hours of usage.
Hydroelectric plants are one way to generate electricity for our homes. The force of gravity pulling water downwards is a type of potential energy (the ability to do work) that is changed into electric energy.
Solar cells can turn light from the sun into electricity (light is another form of energy). A light bulb can turn electric energy back into light energy.
A microphone can turn sound energy into electric energy, and a loudspeaker can turn electric energy back into sound energy.
A battery stores energy in a chemical form, that is turned into electric energy. Some batteries can be recharged, where we turn electric energy back into chemical energy.