Physic Coursework - Squash ball experiment

Fair test

To gain the best possible marks I have chosen only to change two variables. These changes will be in the temperature of ball and the height it's dropped from. I decided to increase the temperature 10 C each time (40 C - 90 C). I decided to drop the ball from 4 difference heights (0.40m, 0.80m, 1.20m and 1.60m). The experiment is going to be repeated 3 times for an accurate average of the height of the bounce. Every other variable will be kept the same.

Equipment

* I will use the following equipment for the experiment.

* 1 squash ball

* 500ml water to heat ball

* 600ml clear glass beaker to measure water in

* Kettle to heat water in

* 1 meter rule to measure heights

* Clear tape to place meter rule to wall

* Tongs to remove squash ball from water after heating

* Heat mat to place squash ball on after removing from hot water

* Towel to dry squash ball with

* Results chart and pen to record results with

Method

* I first gather the correct equipment, listed on previous page.

* I then taped the meter rule to a straight wall using the clear tape.

* I next measured out 500ml of water and heated it in the kettle until it reached the boiling point of 100 C.

* I then measured the temperature using a thermometer. To reach the desired temperature for our results we used ice to cool the water.

* I then placed the ball in the water for exactly one minute.

* I then dried the ball and marked the set lengths we chose for our readings.

* I dropped the ball from each length at the required temperature three times to gain the best results possible and also check for any anomalies. I dropped the ball on the same surface throughout the experiment.

* I repeated this process for each of the set lengths.

Conclusion:

From the results I gathered I can conclude that the relationship between the increase in temperature and the height that the ball bounces, which has great similarities.

For example, when the temperature was 90 C, the ball bounces at heights up to 48cm. Consider that when the temperature was 50 C, the ball only managed to bounce heights as high as 33cm.

The results collected, back up my prediction, which was, as the ball gets hotter the resulting bounce is increase in height at each attempt. As well as coinciding with my prediction, the results agreed with the collision theory. Which is when the ball's temperature is increased, the atoms in the ball gain more energy and move much faster. Therefore when the temperature is decreased the reverse affect would happen.

As the atoms in the ball move more they push each other away, because they have more energy to express. This results in the ball bouncing higher rather than bouncing lower.

I also wrote about the use of certain energies in my prediction. Where I said stated when the ball hits the chosen surface, the gravitational potential energy will change into kinetic energy. Therefore, when the atoms have more energy to start with, the ball will bounce higher after hitting its chosen surface.

The ball is made of rubber and is very flexible. It also deforms when it hits the ground. This change in shape absorbs some energy, and then disperses that energy when turning back to its original shape.

Not every point in my graph perfectly fitted the line of best fit. These were due to inaccuracies that took place during the experiment. As the height from which the ball is increased it is noticeable that there is a small curve in points that were plotted on my graph. This is because as the height increase, air resistance can be ignored, so the ball bounces quickly.

Another factor that we must take into account is the energy loss. As I increase the height from which the ball is dropped from, the energy loss also increases. This is because the ball has greater gravitational potential energy that could be converted into sound and heat energy when the ball is at a greater height. Overall I can say I am very happy with my investigation. This is because the result followed what I predicted and I achieved hardly one anomalous result to account for.

Evaluation:

There were some problems during our experiment. These problems occurred as I was recording my results. No human eye would be able to record the height of the responding bounce of the ball. Because of this restriction I could only record my results to the nearest centimetre (cm). A solution to this is by using a video camera. Also the ball sometimes bounced off the meter ruler. This added to the list of problems.

For future investigations I could use balls made of different materials to see how they would affect the bounce of the ball. To make the measuring of the heights even more accurate, we could use a camera that captures images at very high speeds, for example a flash camera.

It can be important to know how different balls bounce in sport. In tennis the players need to adapt their game, throughout the day, to get the best possible result. When it's the afternoon the ball is given more energy, therefore bouncing off the tennis racket much faster and the players don't need to work as hard. However in the evening the players are forced to work harder due to the fact the sun's energy is not there, so the ball needs to be hit with more power.

Melan Shah 11M