Features: 1.Newton's cradle, named after Sir Isaac Newton, is a device that demonstrates three main physics principles: conservation of energy, conservation of momentum and friction via a series of swinging spheres. 2.Most people think that Isaac Newton invented the apparatus commonly called a Newton's Cradle, but he didn't. English actor Simon Preble invented the device in 1967 and named it in honor of Newton. In 1968 the first portable version hit the market and quickly gained popularity around the world as a fun, educational physics demonstrator. 3.Principle: Not only demonstrates a pendulum, but also shows the Laws of Conservation of Momentum and Energy. Description: Perfect toys for kids who love science.Specifications: Package Dimensions：6 x 5.8 x 5.1 inchesMaterial:steelColor:blackPackage Included: 1*Newton PendulumNotes: 1. Due to the difference between different monitors, the picture may not reflect the actual color of the item. We guarantee the style is the same as shown in the pictures. 2. Please allow slight dimension difference due to different manual measurement.