How do particles behave in the three phases of matter?
Particles behave very differently in the three stages of matter.
In the solid state particles are held closely together and vibrate slightly. They exist in a regular arrangement - there is no regular arrangement in the other states.
In the liquid state particles can move - the movement (temperature dependent) tends to be less frantic than in the gaseous state. The particles are still relatively close together.
In the gaseous state, particles move freely at a frantic pace.
The best demonstration of this is
In the solid state (ice) we can quite clearly observe no movement under conditions that favour the state being maintained (i.e. in a freezer)
In the liquid state (water) we can see the movement of the particles by merely shaking a glass with water.
In the gaseous state (steam) we can see the frantic motion of the particles by observing the steam that rises from a kettle when the water reaches boiling point.