Bazhou's Excellent educational gadget. Not only shows a pendulum, but also shows the laws of momentum and energy conservation.Science toys. When you are tired of studying and working, you can stir balls to hear the clink.Excellent educational and scientific equipment, owning a scientific history and exploring important values in physics.Pull back one or more of the balance balls, release them and the same number of balls will pivot up on the opposite side.Ideal for home decorations, study or desk decoration accessories, etc. Also good for birthday gifts and children's toys.This device demonstrates the conservation of momentum and energy through a series of vibrating balls.Pull back and release one or more of the BalanceBalls and the same number of balls will swing up on the opposite sideSpecification Material: plastic + iron Color: Sliver Size: 14*12*15cm Ball diameter 1.8cm(approx) Scope of delivery:1 x Balance Balls toyProducts from jinyu's store