Materials can be classified in many different ways. They can be divided into natural materials, which come from animals and plants and the Earth's crust, and manufactured or synthetic materials, such as glass, paper and plastics, which are made from other materials. Materials may be solids, liquids or gases, for example wood, water or air.
Materials can be classified according to type, for example metals, ceramics, plastics or fibres. Fibres can be subdivided into two sub-groups:
- natural fibres, for example cotton, wool and silk and
- synthetic fibres, for example nylon and acrylic.
Materials can be grouped according to their properties, for example strength, transparency, flexibility, hardness, conductivity of heat or electricity or magnetism. They can also be grouped according to their uses, for example in building, as clothes or as food.
Materials can be examined in detail and grouped into sets according to weight, strength and flexibility. The children should explore how materials can be changed through the investigation of the effects of heating and cooling on a range of materials and the changes that are brought about when materials are mixed. They will also be introduced to ideas about filtering, evaporation, dissolving and suspension.
Materials and change
Materials can be changed in different ways.
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.
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.
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.
EXEMPLAR 39 - Properties and characteristics of materials (infant classes)
EXEMPLAR 40 - Mixing and other changes (first and second classes)
EXEMPLAR 41 - Properties and characteristics of materials (first and second classes)
EXEMPLAR 42 - Solids, liquids and gases (third and fourth classes)
EXEMPLAR 43 - Materials and change (fifth and sixth classes)