Find one light and one heavy book. Put one of them at the edge of the table and use one hand to gently push it over the edge. Catch it with the other hand about 1 ft=30 cm below the edge of the table. Then do the same with the other book. (Don't choose a book so heavy that it'll hurt your hand, or so valuable that you'll be afraid to damage it!) Compare how much of a " push" your receiving hand feels from the heavy book and from the light book. Explain the difference. [Hint: are the books falling at the same speed at the moment they hit your hand?]