Bowling Ball Pendulum
To demonstrate energy conservation.
Bowling ball on string
Suspend bowling ball from tack on ceiling. Bring ball up to or close to your nose or chin. Release the ball. The ball should swing nicely and return to just below where it was started.
Make sure that the ball has no initial momentum. Be very conscience of our body position at all times, DO NOT lean forward. Also make sure there are no students too close to the path of the bowling ball.