What goes UP

This activity can be adapted to many grade levels. Primary students can collect data and record data using simple data tables. The teacher or role model can do the graphing as a class activity. The comprehension questions can be geared for lower grades.

In this experiment students will study two quantitative variables. In this experiment they determine the exact relationship between the height from which a ball is dropped and the distance that it rebounds.

One meter stick for each group / One centimeter ruler for each group / One tennis ball for each group
Another ball or super ball for each group (upper and middle grades) / Masking tape

Directions

  1. Ask the students to work in groups of three or four. Take turns dropping the ball and recording how high the ball rebounds:
  • Tape a meter stick to the wall in vertical position with one end touching the floor. Be sure the small numbers are by the floor.
  • Have one team member hold the tennis ball so that the bottom of the ball is 40cm from the floor.
  • Have the children make several practice trial runs in order to observe the approximate bounce height. Make sure they drop the ball not throw it.
  • The partner reads the measurement of the bounce height. The child will have to kneel or lie on the floor to do this accurately.
  • The children should record the measurement under trial 1 of the data table. Have the students repeat for trial 2 and trial 3. The partners should trade places for each trial.
  1. After 3 trials have been recorded they should calculate the average. For younger students who can’t calculate averages use an “eyeball” average. Pick the one in the middle. For example: 30cm, 29cm, 32 cm. 30 is the middle one so 30 is the “eyeball” average.
  2. Have the children repeat the procedure for 80cm and again for 120 cm.
  3. Graph your results and discuss the trends that you see. Use the graph

Comprehension questions

  1. What is the manipulated variable?The Drop height
  2. What is the responding variable? The Bounce height
  3. What variables are held fixed during the experiment? Type of the ball, floor and the way the ball is being released.
  4. Why is it a good idea to carry out three trials? To check for big mistakes, to be more accurate
  5. Why do you take an average for the numerical value of the bounce height? To find the best value

Use your graph to answer these questions

  1. If the drop height of the tennis ball is 60cm, what is the estimated bounce height?
  2. If the ball rebounds to a height of 55 cm, from what height do we estimate that itwas dropped?

The students should recognize the direct relationship between drop heights and bounce height. They may want to design their own experiments using other balls and compare the results.