Part I: Children's ideas about life and living processes. Living things. Nutrition. Growth. Responding to the environment. Reproduction and inheritance. Microbes. Ecosystems. Part II: Children's ideas about materials and their properties. Materials. Solids, liquids and gases. Chemical change. Particles. Water. Air. Rocks. Part III: Children's ideas about physical processes. Electricity. Magnetism. Light. Sound. Heating. Energy. Forces. Horizontal motion. Gravity. The earth in space.