Particles exist in three states - solid, liquid, and gas. Solids expand when heated and contract when cooled. Liquids contract when cooled and expand when heated, though water is unique in expanding when cooled until it reaches 4 degrees Celsius. Gases contract when cooled and expand when heated, with gases expanding more than liquids when subjected to the same temperature change. Explosions occur when a gas is made to expand rapidly, creating powerful outward forces.

1. Particle Model
by: Kevin

2. Particles
• Particle are very small piece of matter.
• Particle exists in 3 different states.
Solids Liquid gas

3. Changes in Solids
• Solids expand when heated and contracts when
cooled, that’s why train tracks are give gaps
between them or the pipes that brings hot water.

4. Changes in Liquids
• Liquid contracts when cooled and expands when
heated like solids.
• But water has a property that when it is 4
degrees it will expand until it is 0 degrees.

5. Changes in Gas
• Like solid and liquid, gas also contract when
cooled and expand when heated, if a gas and a
liquid undergo the same temperature rise the
gas expands about 1o times more than the liquid.

6. Explosions
• Explosions happen when a gas is made to
expand very strongly and quickly, this creates
large forces that push on everything round.