Materials and change
 

Materials and change

Materials can be changed in different ways.

  1. Materials can undergo physical changes, where the form and shape of the material is changed. Physical changes usually do not result in the production of a new substance. Examples of physical changes include the freezing of water, bending, cutting materials and making shapes out of plasticine.
  1. Materials can be changed by mixing. This sometimes improves their properties: for example, steel is a mixture of iron and carbon. Sea-water and soup are both mixtures. Sometimes we need to separate these mixtures, and various techniques, such as filtering, decanting and evaporation, can be used.
  1. Materials can be chemically changed to produce another material. For example, chemical changes occur when you burn paper. Rusting is another example of a chemical change, as is cooking an egg.