States of Matter
The particle model explains everything around you through three simple states. Solids have particles packed in regular arrangements that just vibrate around fixed points - think of them as people standing in neat rows, barely moving. This gives solids their fixed shape, volume, and high density.
Liquids are where things get interesting. The particles stay closely packed but can now slide past each other like people in a crowded corridor. They keep similar density to solids but lose that fixed shape.
Gases are the rebels of the particle world. Their particles zoom around randomly with loads of space between them, making gases much less dense than solids or liquids.
Top Tip: Remember that density decreases as you go from solid to liquid to gas because the particles get more spread out!
