The Learning in Science Project (Primary)--LISP(P)--investigated the ideas and interests children have about hot and cold. Data were obtained from 25 children (12 boys and 13 girls), ages 8 to 11, using the "interview-about-instances" (IAI) procedure. Areas investigated included: (1) the meanings of the words "hot,""cold,""colder,""hotter," and "temperatures"; (2) temperature change when water volumes are changed or mixed (both qualitatively and quantitatively); (3) the temperature of ice in relationship to volume of ice and melting; (4) temperature measurement (using the hands and a thermometer); and (5) the process of heating and cooling. Results are presented, analyzed, and discussed in separate sections representing each of these areas. Findings indicate that children's intuitive ideas about temperature and temperature change of objects and events within their normal experience seemed fairly sound, that their subjective knowledge may influence what they actually "observe," and that their understanding of quantitative temperature did not match their understanding of qualitative temperature. In addition, children generally believed there was no difference between heat and temperature and that the greater the volume, the greater the amount of heat (or cold). These results are consistent with the findings reported in other research studies (IAI cards are included in an appendix.) (JN)