The major focus of this unit is on changes where substances do not, from the scientific viewpoint, actually change into other substances. For example, substances may expand or contract upon heating or change form (such as ice to water). Part 1 provides a 12-item instrument to enable teachers to check their own ideas about this topic and to clarify children's views before and after instruction. Part 2 discusses scientists' views on changes produced by the heating and cooling of substances. Part 3 contrasts scientists' views with children's views of four common events, using comments obtained from the in-depth phase of the Learning in Science Project. Events considered focus on: boiling; steam and condensation from steam; water condensing on a cold surface; and melting ice. Part 4 consists of suggested teaching activities designed to build on and reinforce children's views where these views are essentially similar to those of scientists. An overall framework to the sequence of activities (in flowchart format) is included. (JN)