Experiment 1
We made Dennis and Shahbaz swim at a slow pace, close to each other for the full length of the pool after which w conducted an interview to analyse what they experienced in this controlled environment.
Experiment 2
We made both swimmers swim at a fast rate. Shahbaz being closer to the wall. We had instructed Dennis to deviate once he reaches approximately halfway of the pool. After the run we conducted an interview
Experiment 3
We then made the swimmers swim one behind another at around 2 meters from the wall. As this experiment would give us our main data we switched positions to get a more accurate result. We first made Shahbaz swim in the front and Dennis at the back with a distance of around one meter separating them and then made Dennis swim in the front and Shahbaz following him with the same distance in between
Data Collection and Processing
Experiment one
Shahbaz: It was difficult to swim. I found myself exerting more force to stay in line.
Dennis: It was a normal swim.
Explanation
Shahbaz was swimming closer to the wall. Thus waves reflected and Dennis’s waves were pushing him in a diagonal way. As he was instructed to move in a straight line he ended up finding it difficult to swim
Dennis found it comparatively easier to swim. This is because he had very few direct waves obstructing his motion. He thus found the swim easier.
Experiment Two
Shahbaz: Eh Bwana! It was much more difficult to swim at first but when Dennis deviated I found it a little easier to swim
Dennis: At first it was a little bit hard but once I deviated I found it very easy to swim. Anyways the swim was easy.
Explanation
Shahbaz found it very hard to swim at first because of the waves that were hitting him. Remember they are now swimming at a faster pace and hence frequency and amplitude of the wave has increased. After Dennis deviated Shahbaz found it a bit easier to finish the swim.
Dennis had an easy time again as he had fewer waves obstructing him especially after the halfway mark.
Experiment 3
Shahbaz: In the first swim I enjoyed myself it was much easier than all the swims. However in the second one he! It was like not moving at all. I had to use so much energy and effort to move forwards.
Dennis: The first swim was the hardest swim from all the other swims. It was like swimming in a heavy liquid. I had to use so much energy to keep up. In the second swim it was easy and I enjoyed myself
Conclusion and Evaluation
This experiment was very successful because a valid conclusion was drawn from it. The conclusion was that:
“The performance of a swimmer is negatively affected by their interaction with the waves produced by other swimmers.”
We see that also the swimmers performance is affected by reflected waves i.e. from the sides of the pool and hence reflected waves too affect the performance of the swimmer.
Therefore we can modify the conclusion to be
“The performance of a swimmer is negatively affected by waves reflected from the sides of the pool and by waves produced by other swimmers.”
The methods used to investigate in this experiment were highly appropriate but various limitations were present:
- Lack of access to advanced physics knowledge and concepts prevented the formulation of a mathematical relation or data collection
- Lack of strobe photography prevented proper study of the waves in the pool and also data collection
The suggestions to improve the experiment were as follows:
- Construct swimming pools to be of uniform depth to prevent the refraction of waves
- Place plastic or Styrofoam floaters between the swimming lanes to reduce the level of interaction between swimmers and waves
- Prevent the last lanes of the pool from being used
By Hashim Kaderbhai
Aim
To investigate the co-efficient of friction for different types of shoes on different types of surfaces.
Hypothesis
The higher the coefficient of friction a shoe has the more grip it has, hence the more suitable the shoes is for use on the surface being tested.
Apparatus
- 1 white tennis shoe (Reebok)
- 1 red running shoe (Puma)
- 1 soccer boot (Adidas)
- 1 leather office shoe (Weinbrenner)
NB: Only brand name shoes were used due to design.
Variables
There are two variables in this experiment, that is:
Procedure
- Place shoe on different sports surfaces and attach a Newton meter.
- Gently pull the Newton meter until the shoe moves.
- Read the scale on the Newton meter as the shoe moves at constant velocity and take the reading.
- Repeat this thrice with different people pulling the Newton meter for each shoe.
- Calculate the average reading for each shoe and record.
Data collection and Analysis
1.Red Puma
2.White Reebok
3.Adidas stud
4.Office Shoe (Control)
Analysis of Collected Data
From the data collected for the different types of shoes, it was noted that the coefficient of friction was higher in some surfaces than others. For example:
- Red puma has the highest coefficient of friction on the grass.
- White Reebok has the highest coefficient of friction on the squash court.
- Adidas stud has the highest coefficient of friction on the grass.
- Office shoe has the highest coefficient of friction on tarmac. NB: The is a very small margin in the coefficient of friction on the tarmac and concrete.
Explanation
The reason for the coefficient being higher in some surfaces than others is that the shoes are designed to be used on those surfaces, hence the high coefficient thus better grip.
Conclusion
From the experiment our hypothesis was proved to be correct as we found that coefficient of friction was highest on the surfaces the shoes were designed for.
The correct shoes should always be used in sports in order to:
- Avoid injury (e.g. getting blisters) or straining yourself.
- Prevent damaging the sports facilities (i.e. squash court surface)
- Attain optimum performance in the sport.
Evaluation
- Some shoes were found to perform better than others on selected surfaces.
- On examination, it was found that these were the surfaces for which they were designed.
By
Jackson Gachie.
