# Squash Ball and Temperature Investigation

Extracts from this document...

Introduction

Squash Ball and Temperature Investigation

Aim

This investigation will be looking at what factors affect the bounce of a squash ball (in terms of how high it bounces).

## Hypothesis

Having applied my knowledge of the kinetic theory, I believe that the squash ball will bounce higher as the temperature gets higher up to a certain degree. Then, however, I believe that after a certain temperature, the ball will begin to melt and therefore, the bounce of the ball will decrease.

## Prediction

To understand what happens to a ball when it is dropped, we must look at the physics behind it relating to the energy transfers. When you hold a ball above a surface, the ball has potential energy. Potential energy is the energy of position, and it depends on the mass of the ball and its height above the surface (the higher the ball is and the heavier the mass of the ball is, the more potential energy it possesses). The formula for calculating potential energy is PE = mgh where m is the mass in kilograms, g is the gravitational acceleration constant of 9.8m/s2, and h is the height of the ball in metres. As the ball falls through the air, the potential energy changes to kinetic energy. Kinetic energy is the energy of motion. The formula for calculating kinetic energy is KE = ½ mv2, where m is the mass in kilograms and v is the velocity (or speed) in m/sec2. Both potential and kinetic energy have units of Joules (J).

As the ball falls through the air, the Law of Conservation of Energy is in effect and states that energy is neither gained nor lost, only transferred from one form to another.

Middle

25

127

127 ( 5

25

90

26

26

26

26

27

131

131 ( 5

26

100

28

28

28

29

29

142

142 ( 5

28

Having looked at the results and discussed them with my partner, we initially thought that the best height to test from would be from the height of 70cm as it had the least inaccuracies (based on the range) and the ball seemed to produce a good bounce back height at 70cm also. But the teacher stated that the amount of inaccuracies (based on the range) was far to inconclusive and therefore would not help in deciding which height is best to test from.

So we then looked at which height produced the best bounce back height giving us less percentage error again in the larger value of height. This was, from our results, at the 1 metre height, as the average bounce back height was the highest for 1 metre. We then chose to experiment at this height and decided to incorporate it into the final method.

Ideally, heights above a metre would have proven to give us better results with even larger bounce back heights of the ball but because we were limited to perform the test on a bench surface, any height above a meter would prove to be too difficult to carry out as a ladder or other such device would be needed to help drop the ball from the height and this was not practical in the lab.

- Investigating the Time to Heat the Ball

This final preliminary experiment was conducted in order to find out at which time the bounce back height became constant so that it could be heated for this amount of time and then be tested at different temperatures.

The ball would be heated for a range of different times and its bounce back height was observed until it seemed to become constant.

Method

- Using tongs to hold the ball under the water, heat the ball in a water bath (glass beaker full of warm water) to 300C (add ice of necessary to cool down the temperature of the water) for 15 seconds.
- Set up the metre rule in a clamp (to hold it stationary while you perform the experiment) and hold the ball exactly 1 metre above a hard surface (i.e. desk top) and then drop the ball. Ask your partner to measure where the ball bounced up to.
- Repeat this bounce test for the heated up ball three times to gain an average result and record the results in a table.
- Then re –warm the ball in the water bath to 300C for 30 seconds (using the help of tongs to keep the ball under water and adding ice of necessary to cool the temperature of the water).
- Again, hold the ball exactly 1 metre above a hard surface and then drop the ball. Ask you partner to measure where it bounced up to.
- Re- drop the heated ball three times to gain an average result and record the results in a table.
- Continue on as above, increasing the time you heat the ball by 15 seconds each time until the height of the bounce seems constant.

To make the test fair, we kept the temperature of the water at a constant of 300C for each time we held the ball under water (so that each time the ball was supplied with the same amount of heat energy) and the ball was dropped from exactly a metre high each time (measured using a metre rule to the nearest centimetre).

Results

Height of Bounce (cm) | ||||||

Time kept under water (s) | 1 | 2 | 3 | 4 | 5 | Average (cm) |

15 | 25 | 24 | 25 | 25 | 24 | 25 |

30 | 26 | 25 | 27 | 26 | 27 | 26 |

45 | 27 | 28 | 26 | 27 | 28 | 27 |

60 | 29 | 28 | 28 | 28 | 28 | 28 |

75 | 28 | 28 | 28 | 28 | 28 | 28 |

90 | 28 | 29 | 28 | 27 | 28 | 28 |

Calculation of Average

Height of Bounce (cm) | ||||||||

Time kept under water (s) | 1 | 2 | 3 | 4 | 5 | Total | Average (cm) | |

15 | 25 | 24 | 25 | 25 | 24 | 123 | 123 ÷ 5 | 25 |

30 | 26 | 25 | 27 | 26 | 27 | 131 | 131 ÷ 5 | 26 |

45 | 27 | 28 | 26 | 27 | 28 | 136 | 136 ÷ 5 | 27 |

60 | 29 | 28 | 28 | 28 | 28 | 141 | 141 ÷ 5 | 28 |

75 | 28 | 28 | 28 | 28 | 28 | 140 | 140 ÷ 5 | 28 |

90 | 28 | 29 | 28 | 27 | 28 | 140 | 140 ÷ 5 | 28 |

Conclusion

Investigation could be done as to how much the pressure of the ball increases as the temperature increases. Does the relationship with the bounce of the ball and the height match the relationship with the pressure and the temperature? The results could be plotted and then analysed to see what the trend is and how it compares with that of the balls bounce and the temperature.

Because this experiment involves a variety of variables, they could all in turn be tested, i.e. what is the effect of different sized balls being heated up at the same temperature and then being bounced? At what angle would a surface have to be to affect the height of the bounce significantly and does heating the ball before changing the angle of the surface affect how it bounces off the surface? A higher height could be tested, so instead of dropping the ball at 1 metre, you could drop it at 1.5 metres etc and see the effect of the bounce. Different surfaces could be investigated to see just how much they alter the bounce of the ball.

Balls of different materials could be heated and then tested to see how their material affects their bounce height. Endless other such experiments could be conducted at different altitudes, in areas of different atmospheric pressure etc.

This student written piece of work is one of many that can be found in our GCSE Forces and Motion section.

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