Children's and lay adults' views about thermal equilibrium

This paper describes an investigation into the understanding demonstrated by a small sample of students aged 14 and 16 and of adults of a simple thermal system. Interviews explored the constructs and explanatory ideas used by children and adults in interpreting the outcome of a heating experiment in which a candle was used to heat water in a metal can. None of the interviewees appeared to use the scientific model of thermal phenomena in framing their responses, though they did use the individual terms ‘heat’ and ‘temperature’, often incorrectly from a scientific point of view. Heat loss to the surroundings appeared not to be recognized as a factor in the behaviour of the system. Many interviewees' reasoning about heat phenomena used an elementary ‘on = hot/off= cold’ principle. Some implications of these findings for the teaching of heat and temperature are discussed.