Abstract
English The work of Jean Piaget and others on the development of children's thinking, has indicated that far from being the ‘tabula rasa’ of repute, pupils bring to their school learning in science ideas, expectations and beliefs concerning natural phenomena which they have developed to make sense of their own past experiences. These alternate frameworks, in some cases strongly held and resistant to change, in others flexible and with many internal inconsistencies, have their influence on the effectiveness of formal school science programmes. Just as scientists in a period of ‘revolution’ in science have to make a paradigm shift, so pupils in moving from the ideas and beliefs they come to school with, to understanding and accepting the explanatory systems being offered, have to make a considerable journey in thought.