Pendulum experiment

 

Method:

• Set up equipment as follows; Attach bob to string. Tie the string to the clamp leaving a length of 100cm for it to swing from. Make sure the stopwatch is set to 0 and draw up a table to record the results.
• Hold the bob at a right angle from the clamp stand, and let it drop, timing how long it takes to complete one period with the timer.
• Do this for all 10 lengths, timing them five times each, so you are able to work out a reliable average time for each of them.

Conclusion:

From the results I have gathered I can see that the longer the length of the string, the longer it takes for the pendulum to complete one period. This is what I predicted at the beginning of the experiment.

Evaluation:

I think the method I used was a good way of carrying out the investigation, as it was a fair test. The results were quite accurate, but could be more accurate by doing an average of more than five different sets of results. This could also be a fairer test by making sure the string the pendulum is attached to is exactly 90° (right-angle) from the clamp stand.

Doing background research into the pendulum I found that Galileo was the first to properly experiment on this work. He discovered that a pendulum with a length of string four feet long would have a period that would be twice as long as a pendulum with a string one foot long.

So if the pendulum had a string that was 40cms long, it would be twice as long as a pendulum with 10cms.

If the period for a pendulum of 40cms was 1.4, then the time of the period for the pendulum of 10cms should be 0.7.

I tested this theory with my results and found that it was correct, though not entirely accurate, It was roughly the same. The reasons for the average time not being entirely accurate could be a problem with the stopwatch, and also anything measured in this way is not going to be 100% accurate.

The results that don’t fit the pattern of the rest of the graph are called anomalies. An example of an anomaly on my graph could be for length 60cms. The time suddenly jumps up, but then back down again. This could be a problem with calculating the average or maybe one of the trials was extremely off-target.