As a retired teacher I think the concept of the assignment was excellent. Children learn better through hands-on experience. However, as a professional one has to get the approval to teach anything outside of the curriculum from the principal of that school. That way, one will have the backing of the administration, who would get approval from the Board of Education. This would cover you if there is a complaint by a parent(s). This to a great extent handicaps the creativity of a teacher but it also protects them.