Additional Science - What affects the period of a pendulum?

Authors Avatar

ADDITIONAL SCIENCE COURSEWORK – Investigating factors that affect the period of a pendulum.

There are several factors that could affect the period of a pendulum. Factors such as the length of the string, the height from where the ball bearing is dropped from, the material of the ball bearing and the weight of it can affect the period. I can control the length of the string by having several different lengths of string (measured accurately), and change the material of the ball bearing and the size of it.

By doing the preliminary experiments I can see which factor affects the period of the pendulum the most and then have that as my main experiment to elaborate on it. Once that is completed, the results will be recorded and presented in a graph. A conclusion on the results and an evaluation will also be included.

To make the preliminaries and the main experiment a fair test, I will:

  • Have to make sure that the string used to tie the ball to the apparatus will be the same material throughout the preliminaries and main experiment.
  • Keep the size and the material of the ball the same, unless for the experiment where I have to change the ball bearing, because each ball varies in weight so by changing it midway of the experiment would affect the outcomes.
  • Have the same person keeping record of the time taken with the stopwatch, because by changing the person in charge of the stopwatch could result in time differences, as everyone has different reaction times.
  • Use the same ruler throughout the experiments as another ruler could be different by a few millimetres.
  • Drop the ball bearing from the same height and angle, unless for the experiment where I am testing to see how a change in angle and height affects the period.

EQUIPMENT:

  • 1 retort stand                
  • Ball of string                  
  • Metal ball bearings
  • Protractor
  • Stop watch
  • Electronic scaled
  • Scissors
  • 30cm ruler
  • Elastic bands
  • Cello tape

        PRELIMINARIES:

Preliminary Test #1:

In this preliminary I am experimenting to see how the length of the string affects the time period of the pendulum. The independent variable in this preliminary is the length of the string and the control variables are the size of the ball, material of the ball, the height from where the ball bearing is dropped from and the person in charge of the stopwatch. Keeping these variables the same is to make the results as accurate as possible.

METHOD:

  1. Measure out the string carefully with the 30cm ruler, then measure one at 20cm and another at 10cm.
  2. Make sure to leave some extra bit of string to make a loop to attach the ball bearing.
  3. Using the elastic band, attach the ruler to the retort.
  4. Get a protractor and see if the angle is 180° (straight line).
  5. Get a partner to assist with dropping the ball bearing at the set height.
  6. Make sure your partner drops the ball bearing at the same time when you start the stopwatch.
  7. Aim to stop the stopwatch as soon as the ball bearing completes one oscillation.
  8. Once all the lengths of the strings have been tested, repeat the experiment again to see if the second set of results are similar.
Join now!

        FORMULA – Spearman’s Rank:

6∑d2 = 0                    

6 x 0 = 0

n(n2-1) = 3(32-1) => 24

= 1 – (0/24) = 1   <--- As the final answer is 1; this means that there is a strong correlation.

From this experiment, I found that the shorter the string the faster it took the ball bearing to complete one full oscillation. Regarding the reliability of results, I have tried to make to as accurate as possible by using elastic bands to fix the ruler to the ...

This is a preview of the whole essay

Here's what a teacher thought of this essay

Avatar

This is a good report that covers the basics of this investigation. 1. The start of this report should have an introduction. 2. The results tables are well presented. 3. The conclusion is very short and should include data. 4. The evaluation focuses on this investigation well but should include some suggestions for improvements. *** (3stars)