Great Teaching Tools: not only shows the pendulum but also demonstrates the laws of conservation of momentum and energy. Science Toys: when you are tired of study and work, you can swing the ball and hear the click. Excellent Educational and Scientific Gadgets, has its own scientific history and explores the important value of physics. Pull back one or more balance balls and release them. The same number of balance balls will swing to the other side. Very suitable for home decoration, office or desk decoration accessories, etc. Description: The device demonstrates the conservation of momentum and energy through a series of swinging balls. Toss one or more balance balls, release them, and the same number of balls will swing to the other side. Very suitable for home decoration, office or bedroom decoration accessories office, etc. It is also suitable for birthday gifts and children's toys. Specifications: Condition: New Material: plastic Size: 23*18cm Contains: 1 x Balance Ball Decoration Note: 1. Due to manual measurement, please allow 1-2 cm error, please make sure you don't mind before ordering. 2. Due to the different positions of the pictures, the colors may have chromatic aberration, please understand.