Affiliation: | (1) Department of Science Education, Haifa university-Oranim The School of Education of the Kibbutz Movement, P.O. Box, 36910 Kiryat Tivon, Israel;(2) Mathematics Department, Michigan State University, 48824-1027 East Lansing, Michigan, U.S.A.;(3) Computer Laboratory, Michigan State University, 48824-1042 East Lansing, Michigan, U.S.A. |