Resource 3: Background information on states of matter

Background information / subject knowledge for teacher

Basic properties of matter

A solid

  • has a definite shape and a fixed volume
  • is very hard to compress.

A liquid

  • takes the shape of the container and has a fixed volume
  • is hard to compress
  • flows.

A gas

  • has no ‘shape’ and no fixed volume.
  • will spread throughout any container or space available
  • is easy to compress and can be compressed easily.

Some examples of materials that are harder to classify

Some materials appear to be a single substance but aren’t:

  • Sand (or powders, like flour). This flows (like a liquid) but is made of tiny bits of solid. There is air in the gaps between the sand particles.
  • Modelling clay (e.g. ‘plasticine’) is a mixture of a solid and a liquid. It loses its oil as it gets older, and becomes, dry, hard and unworkable.
  • A cloud floats in the air (like a gas) but is composed of many tiny droplets of water in air.
  • A jelly is a mixture in which small amounts of a liquid are mixed into another material which is a solid.
  • Toothpaste is a mixture in which there are small amounts of a solid mixed in amongst another material which is a liquid.
  • A foam is a mixture in which there is a gas mixed into another material which is a liquid.
  • A sponge is a solid with air or liquid mixed with it. As a result it can be compressed, unlike most solids.
  • Some liquids (like tomato ketchup) are thick and do not flow very well, but if you shake them, they become thinner and flow easily.

Resource 2: Corn starch and water

Resource 4: Card sort activity