1. Matter is composed of very tiny particles. The chemical properties of the particles of matter depend on their composition. Their physical properties depend on the forces they exert one ach other and the distance separating them.

2. The particles of matter are in constant motion. The average kinetic energy depends on the temperature.

3. The particles of matter do not lose energy in collisions. When particles collide with each other or with the walls of their container, there is no loss of energy. Collisions of this type are said to be perfectly elastic.