Balancing Ball Newton's Cradles are great for home of the office desk! This 7" tall hypnotizing toy will keep you amused for hours. Newton's Cradle of an odd number of identical steel balls each suspended by a bifilar suspension from a sturdy frame. The balls are aligned along a horizontal line, just touching. When the ball on one end is pulled aside and allowed to swing as a pendulum,it hits the next bal l. The outcome is fascinating, the one ball on the far end is knocked away from the others with the same speed as the first ball had initially and all of the other balls remain nearly at rest !.