As a 13-year-old science whiz, he volunteered as a signaler for the Haganah, the corps that was later to become the Israel Defense Forces, clambering up mountains to send military messages across the country with light-reflecting mirrors. He also belonged to a pioneering youth group that established the kibbutz Maoz Haim, but it was obvious to all he would be more useful to the country as a scientist. After attending the Gymnasia high school in Jerusalem, he earned a B.Sc. in chemistry in 1940 and a Ph.D. in physical chemistry in 1943, both from University College London.