ABSTRACT
Materials can be changed, and these changes can be permanent or reversible. Simple changes in the shape of objects are brought about by the application of forces, and the nature of the change in shape will be a function of the properties of the materials of which the objects are made. The effects of changes in temperature on materials can be explained in terms of the states of matter and changes of state. When clay is heated to very high temperatures in a kiln, the constituent minerals fuse to form a ceramic material. The mixture of solid particles in a liquid is poured into a funnel containing filter paper or other material that will 'trap' the larger particles. The processes that cause changes in substances or materials can include physical and chemical reactions. Physical changes include those that cause a change in shape, a change in state or a physical mixing of substances or materials.
