Solid
* Motion: Particles in a solid are tightly packed together in a fixed, rigid structure. They vibrate in place, but they don't move freely from their positions.
* Spacing: Particles are very close together.
* Energy: Solid particles have the lowest kinetic energy (energy of motion) of the three states.
Liquid
* Motion: Particles in a liquid are closer together than in a gas, but they can move around each other. They slide and flow past each other.
* Spacing: Particles are closer together than in a gas, but further apart than in a solid.
* Energy: Liquids have higher kinetic energy than solids.
Gas
* Motion: Particles in a gas are far apart and move freely in random directions at high speeds. They collide with each other and the walls of their container.
* Spacing: Particles are very far apart.
* Energy: Gases have the highest kinetic energy of the three states.
Key Point: The higher the temperature, the more kinetic energy the particles have, and the more they will move. This explains why solids melt into liquids, and liquids evaporate into gases when heated.
