GRAVITY EFFECT: By throwing one or two balls, you can see the process of weight drop and transfer, and you can see the way energy transfer is so amazing. INTERESTING: Swinging ball desk toy is a great educational gift that demonstrates the conservation of momentum and energy, making learning more fun. STRESS RELIEF: The Physical Swinging Balls are a stress relieving gadget that allows you to take a break from your exhausting life and relax. It is suitable for children with ADHD or autism. EASY TO ASSEMBLE: Physics pendulum balls are very easy to assemble and can be completed in minutes, suitable for offices, classrooms, libraries and more. MULTIPURPOSE: Swinging ball is not only a toy, but also a great desk decoration, you can put it on the table or bookshelf.