Bounciness and Deflection

4.0 based on 2 ratings

Updated on Oct 03, 2014



Grade Level

8 & up

Difficulty Level




Safety Issues


Material Availability

All necessary materials are readily available.

Project Time Frame

4-6 weeks


This project deals with deflection and elasticity.

The goals of this project are:

  1. To demonstrate the property of bouncing in a fresh new way.
  2. To experiment with materials that bounce.
  3. To discuss ways of measuring bounciness.

  1. Computer with internet access
  2. Color printer
  3. Digital camera
  4. Typical office/craft/hobby supplies (such as paper, pens & poster-board, glue, etc.)
  5. A few balls of different sizes and composition



Elastic material returns to its original shape when bent, squeezed or stretched.How fast it does this is a measure of its elasticity.But elasticity is just one way to measure “bounciness.”Another is degree of deflection, which means how far (or fast) a ball will travel after coming in contact with a flat surface.This project involves experiments in deflection.

Research Questions
  1. What causes a ball to bounce?
  2. Are some materials “bouncier” than others?If so, which ones?
  3. How do the size and weight of an object affect its ability to bounce?
Terms and Concepts to Start Background Research
  • Deflection
  • Elasticity

  1. Research related materials (see bibliography below)

  2. Search and print out images of things that bounce.

  3. Collect a few samples of different types of balls.

  4. Carefully record the weight of each ball, and the materials from which it is made.

  5. To calculate bounce rates, drop each ball from the same height onto a hard flat surface, and count the number of times it bounces in ten seconds.

  6. If possible, also measure heights reached on each successive bounce.One way to do this is by filming the bouncing balls against a background that is marked for measurement.Tape wooden yardsticks to the wall, for instance, and film it with an iPhone.

  7. If desired, try a similar experiment using a different type of flat surface.

  8. Carefully record all observations.

  9. Analyze data.

  10. Interpret results in a detailed report.

  11. Include bouncing balls in your science fair display.



Wiki topics: “Deflection” and “Elasticity”

Internet searches of your own choosing:Search for any of the terms listed above (or make up your own phrases to search), and click on any results that interest you.Have fun surfing the net!
