Newtons pendelum

Newtons pendelum illustrates the three main physics principles at work: conservation of energy, conservation of momentum and friction. All the balls are, ideally, exactly the same size, weight, mass and density. The impact of one ball will move another ball of the same mass the same distance at the same speed (energy and momentum conservation law)

The law of conservation of energy states that energy (incuding heat and work) can not be created or destroyed. Energy can, however, change forms, which the Newton's Pendelum represents, particularly the conversion of potential energy to kinetic energy and vice versa. Potential energy is energy objects have stored either by virtue of gravity or of their elasticity. Kinetic energy is energy objects have by being in motion.