1. STATES OF MATTER 1. SOLID: a form of matter that has a rigid, fixed volume and shape. Solids are generally arranged with unique symmetrical regularity. Solids are tightly held together with little space between the molecules (or atoms), they are incompressible. Strong electrostatic forces, which vary from compound to compound, hold the molecules together.

2. The Solid State n Ice is only one form of a solid. n Crystalline solids have ordered uniform arrangement of the atoms. Some crystalline solids are diamonds, metals, and salts. n Amorphous solids are disordered and do not break cleanly. Some amorphous solids are glass and plastics. n All solids have some molecular motion. All solids have vibrational modes of energy.

3. STATES OF MATTER 2. LIQUID: a form of matter that has a definite volume but no specific shape, it retains the shape of its container. It is relatively incompressible. The space between particles and the strength of the forces holding a liquid together is between that of a solid and that of a gas.

4. The Liquid State n The atoms (or molecules) in the liquid state are held together by attractive forces. These forces are stronger than those between a gas but less than the forces holding a solid together. n Liquids have both vibrational and rotational modes of energy. n Surface tension, solubility, and capillary action are all properties of a liquid which aid in distinguishing one liquid from another.

5. STATES OF MATTER 3. GAS: a form of matter that has no fixed volume or shape, it fills all space available irrespective of the container's shape. Gases are highly compressible. There is a great deal of space between particles and the forces holding gas molecules together are very weak

6. The Gaseous State n Steam, vapors, mists, and wind are all different forms of gases. n Gas particles are very weakly held together so the particles are very far apart. n Gases have vibrational, rotational, and translational modes of energy.