The compound pendulum provides still another variation on the same theme for finding g . A pendulum attached to a spring support, so that it can oscillate laterally and vertically simultaneously, offers another approach. With some of these interesting pendulum variations available, different approaches increase student interest. To show the effects of air resistance on falling objects, hold a piece of paper and a ball the same height above the ground. Drop the two simultaneously.
Air resistance prevents the sheet of paper from falling at the same rate.
Take the piece of paper and crumble it into a small ball. Again drop the paper and the ball simultaneously. This time the paper and ball fall at nearly the same rate, since the air resistance on the paper has been reduced. Another way to reduce air resistance on the sheet of paper is to place it on top of a book and then drop the two. The paper remains on top of the book as the two fall.