1. Solids. The particles in a solid are tightly packed together and can only vibrate from their fixed positions.
2. Energy. Adding in energy makes the particles of a substance vibrate faster, breaking the forces of attraction between them and removing energy makes the particles vibrate slower and forces of attraction forms between the particles.
3. Gas. The forces of attraction between the particles of a gas are very weak. The particles randomly and quickly move around in all directions.
