Not just an iconic office or desk toy newtons cradle is actually a physical demonstration of the fundamental laws of physics and mechanics designed in 1967 by englishman simon prebble the cradle contains five balls all exactly the same size arranged so that theyre hanging in a row raise the first ball and let it go and its potential energy is converted into kinetic energy which is transferred to ball two upon impact this energy then passes from balls three to four and then on the five whi