Electricity & Magnetism

Energy vs. Power

The words energy and power are used interchangeably in everyday usage. Physicists, however, have very specific definitions for these words and this exhibit demonstrates the difference between the two concepts. Energy is the ability to do work while power is the rate at which work is done. In this exhibit work is done lighting various lamps. A hand generator is used to charge a set of capacitors to a given voltage. The capacitors then hold a given amount of energy. The capacitors can then be discharged through one of several different lightbulbs that vary in resistance. The energy gets used up at different rates and hence the bulbs have different power ratings (wattage.)