energy

Energy is the ability to do work. Scientists define "work" as when a force moves something. When you lift a brick, you are doing work because you are exerting a force to lift the heavy object. Energy comes in many forms, such as heat, sound, light, electric, and chemical. Energy easily changes from one form to another.

energy
What it is: the ability to do work
Main kinds of energy: potential and kinetic
Main units of measurement: joules or calories
Different forms: atomic, chemical, electric, mechanical, sound, heat, and light
Characteristics: changes from one form to another; can never be destroyed

Image credits: main image: Eric Hamilton.