ニュートンのゆりかご カチカチ玉 衝突球
A device designed to demonstrate the conservation of momentum. It consists of five spheres attached to a frame with wire. When one sphere on the end is lifted and released, its strike on the stationary spheres will transfer force to the opposite end, causing the last sphere to be forced upward.

h4. External link

* "Wikipedia - Newton's cradle":[https://en.wikipedia.org/wiki/Newton%27s_cradle]
newton's cradle