In this activity you will make measurements to determine the average speed of a bouncy ball. Be sure to read the instructions carefully, paying close attention to when to start and stop the stopwatch. You will need the help of a friend or family member to gather the data. Materials:

Superball or other small ball
Masking or cellophane tape
Metric ruler or meter stick
A smooth and level surface
Stopwatch
(online at Interactivate)
Procedure:

Locate an area that has at least four meters of smooth, level surface. This area could be a tile, linoleum, or smooth concrete surface. Avoid carpeted areas if possible.

Set up a straight, level path to serve as the course for a rolling ball. Use a ruler and small pieces of tape to mark the following intervals: start (zero position), 100.0 cm, 200.0 cm, 300.0 cm, and 400.0 cm.
Note: Be sure to leave enough room behind the start position so you can get the ball rolling. Also, do not place tape on any surface that might be marred by the adhesive.

Participant 1 will be the ball roller and should stand behind the start position. Participant 2 will operate the stopwatch and should be positioned to easily view when the ball crosses each marking.

Participant 1 should practice rolling the ball along the path. Give the ball enough energy to travel the entire course without going far beyond the last mark. This requires a gentle, firm roll. Do your best to roll the ball the same way for each trial.

Roll the ball as practiced. Start the stopwatch when the ball reaches the starting position, and stop the stopwatch at the instant the rolling ball reaches the 100.0 cm mark. Record the time as Trial 1 in the table.

Repeat step 5, starting the stopwatch when the ball reaches the 100.0 cm mark and stopping the stopwatch when the ball reaches the 200.0 cm mark. Record the time as Trial 2 in the table.

Repeat step 5, starting the stopwatch when the ball reaches the 200.0 cm mark and stopping your stopwatch when the ball reaches the 300.0 cm mark. Record the time as Trial 3 in the table.

Repeat step 5, starting the stopwatch when the ball reaches the start position and stopping your stopwatch when the ball reaches the 400.0 cm mark. Record the time as Trial 4 in the table.

Answer the questions based on the data you have collected.