Results
The mass was dropped from 90cm for each attempt.
Graph
See attached.
Analysing Results/Conclusion
The results that I have obtained in this experiment agree with my predictions and show us that the heavier an object is, the less time it will take to hit the ground. However, as the mass gets to a certain figure, it will stop getting any quicker unless the height from which they are dropped is increased. This is because the mass does not have enough time to reach its terminal velocity and will keep accelerating until it hits the ground. The results also show us that the more vanes are added to the air break, the longer the mass takes to hit the ground. This is because as more vanes are added, there is more air resistance acting on the air break. This means that it will take less time for the mass to reach its terminal velocity and it will hit the ground at a constant speed.
One observation I made was that there was a big difference in time between when I used a 20g mass and when I used a 40g mass. I think that this is because when I used the 20g mass, gravity and air resistance were balanced almost as soon as I let the mass drop, so it reached its terminal velocity immediately and travelled at a constant speed from the top until it hit the ground.
All of the graphs that I have produced show the same pattern. At first the line goes down at quite a steep gradient, but it soon starts to level off. A very important fact is that the graphs make a shape that will result in heavier masses not having enough time to reach their terminal velocity, therefore not hitting the ground any faster.
Evaluation
I think that the experiment went well. I obtained a few odd results in some of my attempts, but I did the experiment again where I thought there were anomalies until I had sufficient evidence that they were wrong and could replace them with new results. I think that these odd results were due to some aspects of the experiment not being totally fair. However, my new results that replaced the anomalies produced a good graph that agreed with my predictions. There were a few areas where there could be improvement. Firstly, when I wound up the cotton string after each attempt, it was not always wound up in the same way, so when the mass got to the top the vanes were always in different positions, this could have altered the time that the mass took reach the ground. It is difficult to come up with an accurate and fair method to do this part of the experiment as other ways would also lead to some slight mistakes
Also, the time that the mass took to reach the ground was measured by hand with a stopwatch. So the results are not totally accurate as my reflections are not accurate to a 100th of a second. I could get around this problem by using two light gates connected to a stopwatch. This would ensure that my results were accurate. Another way of improving the results would have been to do the experiment more than three times for each weight and number of vanes. This would have made my average more accurate therefore also making my graph more accurate.
Ways of extending this investigation could be to investigate how using vanes of different sizes could affect the time that the mass would take to reach the ground. We could have also increased the height from which I dropped the mass. If we increased the height sufficiently this would have allowed me to find the terminal velocity of each mass.
Name: Daniel Rios-Perez
Form: 4M
Set: 5
