1、【BENEFITS】Cradle never gets old, the concept of Newtons cradle is very pleasant. They are great for psychology, science and physics classrooms and are also great for kids with ADHD or autism. 2、【SCIENCE DESK TOY】 When feeling tired of studying and working, you can stir balls to hear the clinking sound to ease. 3、【SCIENCE PHYSIC EDUCATIONAL KITS】 Help us better understand the concept of conservation of momentum. They are very suitable for psychology, science and physics classrooms, as well as children with ADHD or autism. The balls made with the new technology can be perfectly aligned, so you dont have to worry about tangling the strings. 4、【INTELLIGENT DEVELOPMENT】Asubtle demonstration of Newtons laws of motion and the starting point of physics. (Newtons law of motion) For every action, there are equal and opposite reactions. Enlighten us to better understand the concept of conservation of momentum. 5、【EASY TO PLAY】The same number of balls will swing up on the opposite side and the clicking will go back and forth until it stops, a soothing experience youll enjoy. The bright color will brighten up your work space. 1 x Newtons Cradle Balance Colorful Balls Material: ABS+metal ball Size: about 15*15* 11.5cm Net weight: about 315g Battery: 4 AA batteries (not included in the product) Switch: controllable Luminescence principle: the light from the bottom plate directly shines on the spherical surface to emit light