If the pendulum is moving to the right the force makes it accelerate and the speed increases as it moves towards the centre. On the other hand if the pendulum is moving to the left the force decelerates it and it slows down.
For my experiment I am more curious about the effect it has on the time taken. I will be measure about 5/6 lengths, and minimum 3 measurements for the time to know an average result and a sequence of possible effects you can have when changing the length and. Through this I can then produce a graphical information showing the calculations in a visual format showing how the length of the pendulum effects its time.
Hypothesis : I think that longer the length it takes more time to swing 10 swings because it has a long distance to cover and has a longer vertical and horizontal component to go through where as if the length of the pendulum was short would take less time to cover 10 swings because it has a short distance to cover and has a shorter vertical and horizontal component to go through.
Variables
What am I controlling:-
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Material of the string: I will control it by using the same string throughout the experiment.
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Weight: I will use the same weight while conducting the experiment.
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The starting angle: I will control it by Placing the protractor’s centre at the knot of the string on the clamp and sticking it to the clamp using blue tack.
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Number of swings: I will control it by counting the time it takes to swing 10 swings
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Length of the lab support stand and clamp: I will control it by using the same clamp and not loosening the clamp from the support stand.
What am I changing:-
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The length of the pendulum: I will change it by cutting out the length of the string I want and then attach the same weight I had attached for the rest of them and then I will conduct the experiment.
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Taking accurate measurement of the pendulum: I will control it by measuring the length of the pendulum by a thread and then measuring it using a ruler.
Equipments
- Clamp
- Weight
- Pendulum string
- Stopwatch
- Blue tack
- Protractor
- Result table
- Pencil and Ruler
Method
Note
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The length of the pendulum is measured from the point of support to the center of mass
Figure1 Figure 2
- Set up the apparatus like this as shown in the figure 1
- Cut out a length and tie it to the clamp.
- Measure the total length using a string and then placing it on the ruler to know the measurement.
- Place the protractor’s centre at the knot of the string on the clamp as shown in figure 2 so that the pendulum is measured in the correct angle.
- Pull the pendulum to a degree of 30 with one hand and set the stopwatch in the other hand.
- Let go of the pendulum and start the stopwatch
- Measure the period of swings of the pendulum by counting the time it takes to swing 10 swings
- Stop the stopwatch and note down the time in your results
- Repeat it 3 times and see if your results are approximate to your first result.
- Remove the pendulum from the clamp and cut out a different length, tie it to the clamp and measure it.
- Repeat steps 4-10 with the length of 32.6 cm
- Repeat steps 4-10 with the length of 26.9 cm
- Repeat steps 4-10 with the length of 21.3 cm
- Repeat steps 4-10 with the length of 15.1 cm
- Repeat steps 4-10 with the length of 12.9 cm
Results
Angle – 30°
Weight – 200g
Number of swings – 10 swings
Calculations
Conclusion
From this experiment I have discovered many ways to change the length of the pendulum by measuring with a thread and placing it on the ruler to know it exactly. I have also discovered many ways to measure the time taken for it to swing. The way I used for measuring the time was by leaving the pendulum and then starting the stopwatch and only stopping it when it reached the 10th swing and was already on its way to start the 11th swing. Through this, the time became balanced as I started it late and also stopped it late. If I had more time I would have kept on measuring the time taken for other different length to know a more greater range of effect on the speed and time taken. But I am satisfied with my results as I have got a correct hypothesis and a correct result showing the time taken for the longer length is more whereas the time taken for the shorter length is less. Other than just discovering the relationship between the length and the time I have also discovered that when it has a shorter distance to cover its speed is increased where as the speed is slow when it has a linger distance to cover.
While conducting the experiment there was an obvious error which could have occurred as one cannot be an expert in calculating the exact time for the pendulum to swing with a stopwatch. There may be few people who have an experience and a practice doing this. If was to calculate an accurate measurement I would need more time by timing the swing 20 to 25 times so that I can get an accurate average for the time taken. If I would need a very accurate measurement I would use the latest laser technology which would be better than sitting all day and timing it up to 100 times for each length. Another error which could be involved was measuring the angle . I had no other idea other than sticking a sticking a protractor to the clamp using blue tack and then lifting up the pendulum to a degree of 30 in my view and then leaving it. If I was to measure the angle accurately I would use some new technology which would automatically lift the pendulum at a degree of 30 and leaving it. Since it did not come out accurate, there must be a limitation which suggests the results are not correct.
One limitation is that the time was not measured correctly as it was firstly difficult to handle the stopwatch in one hand and leaving the pendulum from the other hand. It was very confusing by which almost the first 10 minutes were wasted doing this. I would like to do this experiment again and would also like to improve the errors made by repeating the experiment again and again so that I get a better range of results compared to just doing it once.
Even though my results are not very reliable I am still satisfied with it as it is matching my hypothesis and I have also conducted the experiment 3 times to know a better result and also to satisfy that the results are estimated correctly.
