AIM OF THE EXPERIMENT: To find out whether temperature affects how well a rubber ball bounces.
MATERIALS: a tennis ball, a batten a metre long, a freezer.
MATERIALS: a tennis ball, a batten a metre long, a freezer.
Изображение
Stand the batten upright and, holding it with one hand, place the ball on its top end with the other hand.
Let the ball go and watch how high it bounces when it hits the floor. Repeat this three times and estimate the average height of the bounce.
Put the ball in the freezer for half an hour.
Measure the height of the bounce again, releasing the ball from the top end of the batten.
RESULTS: After the freezer the ball does not bounce as high.
WHY? Rubber consists of a myriad of molecules in the form of chains. When they are warm these chains slide towards and away from one another easily, and that is what makes rubber elastic. When they are cooled the chains become stiff. When the chains are elastic, the ball bounces well. For tennis in cold weather it has to be borne in mind that the ball will not be so bouncy. METHOD:
Let the ball go and watch how high it bounces when it hits the floor. Repeat this three times and estimate the average height of the bounce.
Put the ball in the freezer for half an hour.
Measure the height of the bounce again, releasing the ball from the top end of the batten.
RESULTS: After the freezer the ball does not bounce as high.
WHY? Rubber consists of a myriad of molecules in the form of chains. When they are warm these chains slide towards and away from one another easily, and that is what makes rubber elastic. When they are cooled the chains become stiff. When the chains are elastic, the ball bounces well. For tennis in cold weather it has to be borne in mind that the ball will not be so bouncy. METHOD: