The Compound Machine

Activity Home Teacher's Guide Glossary Credit & Thanks


Energy allows us to do work or move things, and can take many forms such as heat, light, sound, movement and electricity. Regardless of what form it takes, energy makes things happen. It takes energy to make something move, heat something up or to change states of matter (solids, liquids and gases).

A push or pull. Forces are acting on you all the time. If you push a chair across the floor, you are putting a force on the chair to make it move. Forces can also hold you in place, like the force of gravity.

Friction :      
A force that opposes or slows down the motion of an object.

A force of attraction. It is the force that holds you down and keeps you from floating into space. The force of gravity exists between objects, such as the Earth and you.

The process of something moving. Motion requires a force of some kind to be put on the object moving.

A force in which something is brought closer to the person or object exerting the force.

Moving something by putting the force behind the object being moved.

The response of mass to the force or pull of gravity. Your weight on Earth is determined by the strength of gravity. You would weight less on the moon, since it does not have as much gravity.