The substantialisation of properties in pupils' thinking and in the history of science

The ideas used by some 13 year old pupils to explain the properties of substances and their changes are analysed and discussed in this paper. A significant number of pupils use explanations which have been categorised as ‘substantialisation of properties’. This categorisation has been justified in this paper on the basis of a study of the history of science. An analysis of the consistency with which students use this type of explanation, and factors favouring its use, has been carried out.