The classic executive desktop toy - in miniature form! And it works! This plastic-framed Newton's Cradle measures 3" long and 3" tall but it still packs that momentum-conserving punch when the .5" diameter metal balls hit each other. Simply pull back one or more of the balls and watch them strike the rest only to see a single (or more, equal to the amount you pulled back in the first place) ball fly out! This Mini Newton’s Cradle captivates attention with each collision of the swinging balls and looks perfectly at home in a small space!