# Newton’s Cradle

Using Toys to Understand Physics

If you want to try making one out for yourself, check out this video!

Or try out this free simulation:

https://www.myphysicslab.com/engine2D/newtons-cradle-en.html

Law of Conservation of Energy

Energy can never be created or destroyed, it can only be converted into different forms. In the case of Newton’s Cradle, potential energy → kinetic energy. In the video of the newton’s cradle, the potential energy of the first ball is converted into kinetic energy and is transferred down the line of balls. This leads to the ball on the opposite end swinging in the air.

Law of Conservation of Momentum

This principle states that when two objects collide, the total momentum of the objects before the collision is equal to the total momentum of the objects after the collision. In the case of the Newton’s Cradle, when the first ball hits the second ball, its momentum isn’t lost. Rather, its momentum is transferred to the second ball, third ball, and so forth. This results in the last ball swinging in the air almost at the same momentum as the first ball.

Friction

Friction is defined as the resistance that one surface or object encounters when moving over another. In Newton’s Cradle, friction prevents the balls from staying in motion forever. A small part of friction comes from air resistance in this case, and the rest of the friction is between the molecules of the balls. The balls lose energy as they travel through the air and when the balls collide they convert kinetic energy to heat and sound. This eventually results in the balls coming to a standstill.