Newton's cradle Newton's cradle Newton’s cradle is a device that demonstrates conservation of momentum and energy using a series of swinging spheres. When one sphere at the end is lifted and released, it strikes the stationary spheres, transmitting a force through the stationary spheres that pushes the last sphere upward. The last sphere swings back and strikes the still nearly stationary spheres, repeating the effect in the opposite direction. The device is named after 17th-century English scientist Sir Isaac Newton. It is also known as Newton's balls or Executive Ball Clicker. A typical Newton's cradle consists of a series of identically sized
Department of Conservation and Recreation Department of Conservation and Recreation The Department of Conservation and Recreation (DCR) is a state agency of the Commonwealth of Massachusetts, situated in the Executive Office of Energy and Environmental Affairs. It is best known for its parks and parkways. , the Commissioner of the DCR is Leo Roy. The DCR's mission is "To protect, promote and enhance our common wealth of natural, cultural and recreational resources for the well-being of all." The agency is the largest landowner in Massachusetts. The Department of Conservation and Recreation was formed in 2003 under Governor Mitt Romney, when the former the Metropolitan District