how far away from the stand the pendulum is swung from.
Fair Test: -
In order to keep my investigation a fair test, I will keep all the dependent variables the same, only changing my chosen variable. I will also keep the number of oscillations the same.
Prediction: -
I predict that as the weight increases the time for one oscillation will decrease. This is because I think that a heavier mass will create a greater pull on the pendulum, therefore causing the time period for one oscillation to decrease.
Apparatus: -
I am going to take five readings for each mass, divide the number by ten to find the time taken for one oscillation and then find an average for the five results in order to make my results as accurate and reliable as possible.
Preliminary Work: -
See graph paper for graph of preliminary results.
Analysis
My preliminary results showed that there was hardly any difference in the time period for one oscillation, using different masses. Therefore, I decided to find out the constant for a simple pendulum from my results.
The equation for this is:
T=√ l / g 2π
As seen on my graph, there is only a slight change between all the results, therefore showing that the mass on the end of the pendulum has no effect on the time taken for one oscillation.
This can also be proved through the use of the equation above. This is because mass is not included in the equation therefore must have no effect on the time taken for one oscillation.
The average of all my results is approximately 1.55 secs for one oscillation, which means that T should also be approximately the same.
So,
T=√ l / g 2π
T=√ 0.6 / 9.8 x 2π
T=0.2474356 x 2π
T=1.554683726
T=1.55 secs (2dp)
This is also shown on the graph on the next page.
Originally, I predicted that as the mass increases the time for one oscillation decreases. However, from my preliminary work I found that mass has no effect on the time taken for one oscillation. Therefore, I found the equation for the constant to find out if my results fitted the equation. From substituting the relevant information into the equation, I found that my results do fit to the constant; therefore proving that mass has no effect on the time period for a simple pendulum.
Evaluation
It is obvious from the graphs, results table and the equation that the mass on the end of a simple pendulum has no effect on the time period of the pendulum.
The investigation was successful and there were no anomalous results. My results are fairly accurate although there may be a slight error in stopping the stop watch, whether or not the string was the right length every time and whether or not the pendulum was swung from the same height every time. Apart from these slight errors, my results are fairly accurate. These errors may also have affected whether or not my investigation remained fair throughout.
Due to the amount of results taken and the lack of anomalous results, I think that my results are reliable. From my results, I was also able to come to a sufficient conclusion for my investigation.
If I were to do this investigation again I would make several changes. Firstly, I would probably make sure that my chosen variable had an effect on the investigation and secondly, I would make sure that my investigation was more accurate. I would by making sure that the string is at the exact height every time, making sure that the pendulum is swung from the same height every time and by being more accurate in stopping the stopwatch.
