Three and a half centuries ago, a five-year experiment was conducted involving the growth of a willow tree in a pot which received only water. The conclusion, that a tree is therefore made solely from water, was not so ridiculous when there was still general acceptance of the Aristotelian view of only four "elements": water, earth, fire and air.…

Discussed are the implications of the three main stages of conceptual change--"awareness, disequilibrium, and reformulating"--on misconceptions of grade 10 students in Israel. The difficulties and problems encountered with the procedure are included. (KR)