Bouncing Ball Design

JACOB YAMBASU BOUNCING BALL DESIGN Title: Bouncing Ball Criteria: Dn, DCP, CE Research Question: What is the relationship between the height at which a tennis ball is dropped and its maximum rebound height? Hypothesis: For small heights, the drop height will be proportional to the bounce height because when the drop height is reduced, the ball hits the ground with less force and therefore the rebounded force will be less and the ball would rebound to a lower rebound height. Apparatus • • • • •

Tape Measure Tennis Ball Ruler Flat Horizontal Surface Vertical Section of Wall

Variables Independent Variable •

Drop Height – The initial height the tennis ball drops

Dependant Variables •

Rebound height – Maximum height of first bounce

Controlled Variables •

•

Surface on which the ball bounces – This is because different balls have different degrees of hardness and therefore different hardness of floors will cause different absorption of energy when the ball hits the ground causing varying rebound heights for the same drop height. Tennis Ball – The same tennis ball would be used because the mass will affect the acceleration of the ball and also different balls absorb energy to different extents on impact.

JACOB YAMBASU BOUNCING BALL DESIGN

Procedure 1. Cellotape a tape measure against a vertical wall with measurements ranging from 0 cm to 200cm. 2. Let one experimenter hold the tennis ball with the fingers and place the top of the ball in line with the 200cm mark of the tape measure. 3. The second experimenter should be positioned near to the floor. 4. The first experimenter should drop the ball from the 200cm mark whiles the other experimenter observes the height of the bounce (this is a trial drop since the second experimenter needs to know the approximate height of the bounce since he has to be level with the measuring scale to avoid parallax error.) 5. This observed height should be marked with a ruler by the second experimenter. 6. To ensure accuracy, the same drop is repeated before the rebound height is recorded. 7. Repeat these steps twice for drop height increasing and drop height reducing for about 10 different drop heights. 8. Find the average for the rebound heights Precautions 1. Ensure that the surface of the floor is horizontal because on trial runs it was observed that when the ball landed on a slanted surface the ball rebound with a horizontal and upward motion instead of a perpendicular upward motion.