3.2 - The Particle Model

Explaining density with the particle model

• Density is a measure of how much mass is packed into a given volume.
• The more tightly packed the particles are, the denser the substance.

Comparing the states

• Solids - Usually the densest state. Particles are packed tightly together, so a given volume contains a lot of mass.
• Liquids - Usually slightly less dense than solids. Particles are close but randomly arranged with small gaps.
• Gases - Much lower density. Particles are far apart with large empty spaces between them, so a given volume contains very little mass.