Science Starter, 9/10/12

Watch this clip that demonstrates Newton's Cradle, a scientific toy. As you watch, you will notice that all balls are the same size and mass, hanging side by side in contact in a row on bifilar supports. When one is pulled back and is released, one ball on the opposite side moves off, which in turn causes the one on the opposite side to pop off, etc. If two are pulled back at the same time and dropped together, two move out together at the other end. Pull back three, release all three, and three move out at the other end. Pull back four, and four pop from the other side... Can the balls count? How do they know? Explain the physics behind this tricky toy using the concept of energy (potential, kinetic, law of conservation of energy, energy transfer...).