Features:Not only demonstrates a pendulum， but also shows the Laws of Conservation of Momentum and Energy.Friction and damping effects are also observed.Often used as a toy to amuse people.Includes steel balls， plastic frames and base.Great gift for everyone.Size: 87x75x95mm(LxWxH)Net weight:96gPacking content:1 x Balance Balls Desk Physics Science Pendulum Desk Toy