Raw or Cooked

1 hard boiled egg
1 raw egg
small bowl
1) Place both eggs in front of you and ask the girls to tell you, without breaking them, which egg is cooked and which is raw.
2) When they can't tell you, tell them that you are going to show them how to tell them apart.
3) Spin both eggs on their sides, at the same time with the same force. Then, point to the egg that is making the fastest and even spins and tell them that that egg is the cooked one. Crack the other egg into the bowl to prove it. Explanation: The center of the egg's gravity is the key to this trick. A raw egg's center of gravity is the yolk. Because all of the egg's insides are liquidy, the yolk moves, and the spins are slowed and offset by this. A cooked egg's center of gravity is the yolk too, but since the egg is cooked, nothing moves inside, making it easier for the egg to spin around the center of gravity.