Pupils from a Borehamwood school used science to try to come up with an impregnable safe.
Year 12 students from Yavneh College competed against nine other teams to design a safe that can be opened by solving two physics riddles.
The strongboxes will be put to the test on Sunday during the UK tournament held at UCL Academy in Swiss Cottage.
Teams will be judged by physics experts from the Weizmann Institute of Science in Israel and by Professor Herbert Huppert from the University of Cambridge.
The top three will win a grant to enable them to travel to Israel for the International Safe Cracking Tournament.
The competition, which is in its second year, is designed to allow students to discover how important creativity is in science, and how it can be great fun.
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