SciencePurchase Newton's Cradle Art in Motion, 7 1/4-Inch Balance Balls - Black Wooden Base

The classic desk accessory is both art-in-motion and proof of Newton's Principle that "action and reaction are equal and opposite."

Lift one of the 5 steel balls at either end and let it swing back--the ball at the other end will swing out the same distance as the one you lifted, proving the scientific theory and mesmerizing you for hours.

Use it to waste time, relieve stress, tune out boring coworkers, or schooling youngsters in physics. Fair warning: it's totally addictive! 7.25".