Discussion
What happened?
There were two tennis balls. One placed in the freezer for 20 minutes whilst the other was left alone. Both were dropped from a height of 1m and the height of their bounce was recorded. The results showed the normal tennis ball bounced higher.
Why did this happen?
Tennis balls are filled with gas that can both expand and contract. Once a ball hits the ground, the surface of the ball pushes into itself and the gas inside, which is forced to compress. The bounce then occurs as a spring effect due to the gas, which occurs once the ball returns to its original shape. The investigation involves a tennis ball to be placed in the freezer for 20 minutes which means the air molecules inside are both sluggish and contracted resulting to its low bounce in comparison to the normal ball which has an even temperature pressure. The longer it is placed in the freezer the lower the temperature which results to low pressure. The lower the pressure means the smaller the bounce which is exactly what took place in the investigation. This means, the hypothesis stated is correct and is supported by the data produced via the investigation.
There were two tennis balls. One placed in the freezer for 20 minutes whilst the other was left alone. Both were dropped from a height of 1m and the height of their bounce was recorded. The results showed the normal tennis ball bounced higher.
Why did this happen?
Tennis balls are filled with gas that can both expand and contract. Once a ball hits the ground, the surface of the ball pushes into itself and the gas inside, which is forced to compress. The bounce then occurs as a spring effect due to the gas, which occurs once the ball returns to its original shape. The investigation involves a tennis ball to be placed in the freezer for 20 minutes which means the air molecules inside are both sluggish and contracted resulting to its low bounce in comparison to the normal ball which has an even temperature pressure. The longer it is placed in the freezer the lower the temperature which results to low pressure. The lower the pressure means the smaller the bounce which is exactly what took place in the investigation. This means, the hypothesis stated is correct and is supported by the data produced via the investigation.
Evaluation
Validity:
By changing one of the temperatures of the tennis ball used in the investigation, answering the aim was possible. This along with making sure both balls were dropped from the same height with the same pressure and measured using the same tape, implies the results provided by the experiment are accurate as both balls were treated identically to one another. By making sure the variables: same ball, same pressure and same tape took place in the replication of the experiment, it meant the investigation was a controlled experiment and valid. |
Reliability:
The repetition of the the investigation was performed 3 times to achieve accurate results. This prevents space for unusual or incorrect results to take place and further providing incorrect conclusions. By calculating the average of the 3 trials, this makes the conclusion further reliable.
Limitations:
Using a tool that could measure the height of the tennis balls' bounces with precision was a limitation that occurred in the experiment. Without the proper tool, the experiment was vulnerable to miscalculations that affect the conclusions of the investigation. The experiment also lacked an accurate method of making sure the balls were all dropped directly down. The smallest curve in the drop of a ball, can affect how it makes impact with the ground and further affect the bounce of the result. This may provide false data and a false conclusion.
Improvements/Successes:
Improvements could be made in the investigation if there were another person observing the bounce of the tennis balls to make the experiment more accurate. For being a simple experiment, for further evidence for the conclusion, the investigation could have been repeated a few more times.
The biggest success was being able to understand the science behind why the cooler ball bounced higher than the normal one and putting into different words for others to understand.
The repetition of the the investigation was performed 3 times to achieve accurate results. This prevents space for unusual or incorrect results to take place and further providing incorrect conclusions. By calculating the average of the 3 trials, this makes the conclusion further reliable.
Limitations:
Using a tool that could measure the height of the tennis balls' bounces with precision was a limitation that occurred in the experiment. Without the proper tool, the experiment was vulnerable to miscalculations that affect the conclusions of the investigation. The experiment also lacked an accurate method of making sure the balls were all dropped directly down. The smallest curve in the drop of a ball, can affect how it makes impact with the ground and further affect the bounce of the result. This may provide false data and a false conclusion.
Improvements/Successes:
Improvements could be made in the investigation if there were another person observing the bounce of the tennis balls to make the experiment more accurate. For being a simple experiment, for further evidence for the conclusion, the investigation could have been repeated a few more times.
The biggest success was being able to understand the science behind why the cooler ball bounced higher than the normal one and putting into different words for others to understand.