Density

Describe arrangement of particles in a solid

Particles are very close together

Arranged in a regular pattern

Particles vibrate but do not move

Arrangement of particles in a liquid

Particles close together

Not arranged in a regular pattern (irregular)

Particles can move around each other

Arrangements of particles in a gas

Particles are very far apart

Not arranged in any pattern

Particles are moving very rapidly

What is density

The mass for a given volume

Example of high density material

Brick as it has lots of mass packed into its volume

Example of low density material

Polystyrene as it has a lower mass packed into its volume

Density formula

Mass / volume

Units of density

Kg/m3

Density of solids

Very high density

Because the particles are packed closely together, solids have a lot of mass for their volume

Density of liquids

Usually have a high density

Particles are close together, so liquids have a lot of mass for their volume

Density of gas

Low density

Particles are very far apart, so gases only have a small mass for their volume

Exception to solid density

Polystyrene is a solid but has a low density. This is as it has a very open structure and is full of air spaces, so has a small mass for its volume