Diagram
Preliminary Work
Before doing the actual experiment, to prove my prediction I did some preliminary work to which ball I should use to do the experiment with; a tennis ball or a table tennis ball. I compared my results and chose the ball that I found most reliable from the results.
TENNIS BALL
TABLE TENNIS BALL
Safety and Fair Testing
- When tightening the clamp head, make sure fingers and other body parts are out of the way.
- The ruler is securely fixed to the clamp stand.
- The same person drops the ball and measures the ball bounce height.
- The ball is bounced at least 3 times from one height to ensure accurate, reliable results.
Constants
Data not changed during my experiment:
- Ball – a tennis ball
- The surface the ball is dropped on
- The person dropping the ball and the person measuring the bounce difference.
Method
- Set up apparatus as shown in the diagram
- Drop the ball from a height of 2m onto the floor.
- Decrease the height by 20 cm each time until a height of 20 cm. (as shown in the preliminary results table).
- Repeat all 3 times and take averages for accurate results.
Results
Graphs
Conclusion
My conclusion is that my prediction is correct:
‘When you decrease the height you release the ball from, the height the ball bounces back up to will remain the same’
My results show this. The differences between the height the ball bounces back up to ranges between 9cm and 12cm. As this investigation was measured by the naked eye, I feel that these are accurate results.
When the ball hits the floor, energy is being transferred. As the ball is being dropped from the same height without any force, the amount of energy transferred stays the same therefore the amount the height decrease by stays the same.
Evaluation
My plan for this investigation was successful as my results show. They are reliable and they were easy to obtain with no problems when carrying out the investigation. My results were reliable as the data spread was closely ranged in the 3 separate drop attempts. For example:
My investigation could have been more accurate in a few ways. Different apparatus, such as video recording equipment, could have been used to get the exact height or the ball bounce. Frames could have been frozen when the ball had reached the top of the rebound bounce to get the most accurate result.
The investigation could have been extended so that there were other variables other than the drop height. The surface that the ball was dropped on could have changed, the ball could have been changed, like in my preliminary investigation or the pressure applied when letting go of the ball could have changed. More force could have been applied.
