Property that matter has to remain in its present situation, whether in motion or at rest.

The larger the mass of a body, the harder it is to alter its movement, and the greater the inertia. Mass measures the inertia of a body.


Two bodies cannot simultaneously occupy the same place in space.

Air is a space-consuming material that does not let water in by wetting the paper.


Property of matter consisting in having reduced volume when subjected to a certain pressure.

By pulling the plunger, the inside of the syringe is filled with air. When the plunger is pushed, the air inside it is compressed because its outlet from the syringe has been blocked by the finger.