Balls That Hit Each Other

How Does Newton'south Cradle Piece of work?

Newton'due south Cradle demonstrates some simple laws of physics. (Paradigm credit: <a href="http://www.shutterstock.com/gallery-60335p1.html">ErickN</a> | <a href="http://www.shutterstock.com">Shutterstock.com</a>)

Whether you know it as Newton's Cradle or the Executive Ball Clicker, chances are you've seen the educational desk-bound toy that seems to defy explanation. The device consists of a row of v metal balls — positioned to just barely affect one another — suspended from a frame by thin wires.

When a ball on one terminate of the cradle is pulled away from the others and then released, it strikes the side by side brawl in the cradle, which remains motionless. But the ball on the opposite cease of the row is thrown into the air, then swings back to strike the other assurance, starting the chain reaction again in opposite.

How does Newton's Cradle work? The device tin can exist explained with some of the cardinal principles of physics and mechanics (every bit theorized past Sir Isaac Newton, René Descartes and others).

Newton's Cradle aptly demonstrates the principle of the conservation of momentum (mass times speed). This principle states that when two objects collide, the total momentum of the objects before the collision is equal to the full momentum of the objects after the standoff.

In other words, when the get-go brawl of Newton'due south Cradle collides with the second, the start ball stops, merely its momentum isn't lost, simply transferred to the 2d ball, then the 3rd, then the 4th, until information technology reaches the very final ball. Y'all witness this conservation of momentum as the last ball swings into the air with nearly the aforementioned momentum equally the first ball. Thus, if two balls are lifted into the air on one end of the device and released, so two balls on the opposite end will swing in response.

This continuous clicking of assurance is besides proof of Newton's police of the conservation of energy, which states that free energy can't be created or destroyed but that it tin change forms. Newton's Cradle demonstrates this last part of the law quite well, as it converts the potential energy of one ball into kinetic energy that is transferred downward the line of balls and ultimately results in the upward swinging of the last brawl.

Follow Elizabeth Palermo on Twitter @techEpalermo or on Google+. Follow LiveScience @livescience. We're also on Facebook & Google+.

Elizabeth is a Live Scientific discipline associate editor who writes about science and technology. She graduated with a bachelor of arts degree from George Washington Academy. Elizabeth has traveled throughout the Americas, studying political systems and indigenous cultures and educational activity English to students of all ages.