SOME THOUGHTS ON TEACHING CHANGES OF STATE AND CHEMICAL CHANGE

Chemical change is a central theme of Chemistry which has itself been called the central science. This was the title of a popular American text book. I am thus putting forward the idea that chemical change is an idea central to science as a whole, so that it would be one of the ideas children should understand clearly whilst at school. This is both because that understanding is important to handle chemistry at higher levels and also because in the world outside schools it is essential to the understanding of the great issues of our time. The article goes on to consider methods of introducing the concept of physical and chemical change, comparing the differences between physical and chemical changes; it includes some literary and anecdotal evidence about physical and chemical change, children's science and other research about physical and chemical change, models of physical and chemical change and practical experiments to illustrate physical and chemical change