Children's understanding of changes of state involving the gas state, Part 1: Boiling water and the particle theory

As part of a three‐year longitudinal study which explored the development of children's concept of a substance (ages 11 to 14), this paper reports the findings in relation to children's understanding of boiling water and particle ideas. Evidence is presented which suggests that, for most of the pupils, particle ideas provided the means for them to begin to accept that the bubbles in boiling water were the water changed to the gas state. The importance of this, in terms of children's understanding of a sample of gas as a sample of a subtance, is discussed. It is argued that boiling water must be seen to have a curriculum significance which goes far beyond its association with a defined temperature.