For factor 2 (Different surfaces) I predict that if the ball is dropped on a harder surface then the ball will bounce higher than on a softer surface because the particles in a harder surface like wood are more packed together so the energy that will be rebounded back onto the ball will be greater causing the ball to bounce higher.
For factor 3 (Different temperatures) I predict that if the ball is hotter it will bounce higher because If the ball is hotter then the particles inside the ball will obtain more energy then collide with each other and the walls of the ball more often causing more pressure on the ball so when the ball bounces there will be more pressure on the walls of the ball causing it to bounce higher.
Apparatus
Squash ball
Meter ruler
Water bath
Gauze
Sheet of rubber
Wood (Safety mat)
Cling film
Lab floor
Carpet
Method
For factor 1 (Different heights)
- Hold meter rule up and drop the squash ball at 40cm, 60cm, 80cm and 100cm 6 times for each and note down how high the ball bounces at each height.
For factor 2 (Different surfaces)
- Hold up meter rule and drop squash ball at 1 meter 6 times each on an equal amount of each surface then note down how high the ball bounced on each surface.
For factor 3 (Different temperatures)
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Wrap the squash ball in a sheet of cling film and leave the ball in a water bath for 3 minutes at 30°.
- Take the ball out of the water bath and unwrap the squash ball.
- Drop the ball at shoulder height 6 times and note how high the ball bounced each time.
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Repeat the experiment but at 40°. Then at 50° and finally at 60°.
Fair testing
Make sure when we drop the ball it is dropped at the same height each time unless otherwise specified. Make sure the squash balls aren’t in the water baths over 3 minutes and keep the same amount of each surface each time.
When we do the temperature experiment any gust of wind from the lab could change the temperature of the ball and then give us false results so we will make sure any windows are closed during experiment.
Results (averages at bottom)
Factor 1 (different heights)
Factor 2 (Different surfaces)
Factor 3 (Different temperatures) Alternate method***
Factor 3 (Different temperatures) Water bath method****
Averages
Factor 1:
Height (cm) Average height (cm and 1 d.p)
20 8.5
- 9
- 15.5
- 20
- 24
Factor 2:
Material Average height (cm and closest number)
Rubber 26
Carpet 30
Gauze 24
Safety mat 24
Lab floor 23
Factor 3 Alternate method:
Temperature ( °c) Average height (cm and 1 d.p)
30 27
40 29.5
50 33
60 40
Factor 3 Water baths:
Temperature ( °c) Average height (cm and closest number)
0 18
30 25
40 31
50 37
60 44
*** We had to use a alternate method for this but we knew that the results weren’t going to be very accurate so when we were able to do the water bath experiment we did. This method is the same as the original except we used a Bunsen burner, a beaker and a thermometer.
**** We added 0 as an extra value so we had more range of values.
Conclusion
For factor 1 (Different heights) we found out that the ball bounced highest at 100cm because the gravitational potential energy was greater so when the ball was dropped there was more kinetic or movement energy so when the ball hit the floor the force that hit the floor rebounded back and caused the ball to have kinetic energy in the other direction and bounce upwards until gravity got greater than the upwards kinetic energy and the ball fell back down which proved my prediction correct.
For factor 2 (different surfaces) we found out that the ball bounced highest on the carpet. So when the ball was bounced on the carpet the movement and gravitational energy from ball rebounded off the carpet; which acted as an elastic springboard and made the ball bounce higher than it would on any of the other surfaces as they didn’t possess the same properties as the carpet although the rubber was close. This proved my prediction to be wrong.
For factor 3 (Different temperatures) we found that when the ball was hotter it bounced highest because when the ball was hotter the particles inside the ball obtained more energy then collided with each other and the walls of the ball more often causing more pressure on the ball so when the ball bounced there was more pressure on the walls of the ball which caused the ball to bounce higher which proved my prediction correct.
Evaluation
The experiment went well except for when we couldn’t get the water baths so we was forced to do an alternate method but we made sure that when we could get the water baths we did the experiment again to get better and more accurate results (we included the alternate method in the graphs to compare the difference). The rest of the equipment was easy to supply and set up. We got lots of anomalous results for the temperature experiment when using the alternate method maybe due to over or under heating or by a human error e.g. waiting too long to bounce the ball. We got 2 anomalous results for the height experiment which are circled on the graph maybe because the height wasn’t properly measured, the only anomalous result for the water bath method of the temperature was the 0°c reading because we only did that to get more of a range of results and we never done 10°c and 20°c so the mark on the graph was different or because the temperature wasn’t completely at 0°c because we used ice and the temp wasn’t completely at 0°c which maybe to cause it to bounce higher.
To improve the investigation I could of done the experiments maybe just once more to get even more accurate results or I shouldn’t of done 2 factors instead of 3 so I could of concentrated more on the other factors.
