Answer by
kevincai96 (669)
Look on google, this should be your first option. However, make sure your son knows what he is doing. Being an experienced rocketeer, many things could go wrong with staging, so I don't reccommend it as a science fair project. A simpler idea would be better. Nonetheless, if/it is a rocket motor type (not water/rocket) then a search/engine should/be enough.