1. Solids, Liquids, Gases  Matter is made up of tiny particles.  The way these particles interact with each other helps determine the state of matter.  Matter has three states:  Solids  Liquids  Gases

2. Solids  Have definite sizes and shapes  Particles of matter are tightly packed together, vibrate in place, particles are touching  Keep shape, volume stays the same

3. Liquids  Have definite sizes but not shapes  Assume the shape of the container they are in but volume stays the same  Surface will always stay horizontal  Particles of matter are close together with some movement, flow freely, some particles still touching

4. Gases  Have neither a definite size nor definite shape  They expand to fill the container that they are in, volume can change  Particles of matter are spread out, flow randomly, particles do not touch

5. Changes in State  To change matter’s state you must increase or decrease the energy of the particles that make up the matter.  Adding heat makes the particles move faster and spread out so matter moves toward a gas state.  Taking away heat makes the particles move slower and closer together so matter moves toward a solid state.

6. Changes in State  Solid to Liquid = Melt  Liquid to Gas = Evaporation  Gas to Liquid = Condensation  Liquid to Solid = Freeze