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Introduction

Plan Aim: Find which factors/variables affect a pendulums period (time taken to do one oscillation) and design an experiment to test whether the two of these factors/variables do actually affect a pendulum. Possible Variable That Might Affect a Pendulum: Length Mass Friction with air Momentum given to pendulum Gravitational Potential Energy-force due to gravity Prediction: I predict that both length and mass will affect the period of a pendulum. An increase in length will mean it will take the pendulum longer to complete a period. An increase in mass will also mean the pendulum will take longer to do a complete period. Scientific Knowledge: I based my prediction on the following scientific knowledge. I think length will affect the time taken for a pendulum to complete a swing because of the following reason. A pendulum is able to work when the bob (weight at the end of a pendulum) is raised to an angle larger than the point at which is vertically suspended at rest. By raising the bob, the pendulum gains Gravitation Potential Energy or GPE, as in being raised, it is held above this point of natural suspension and so therefore is acting against the natural gravitational force. Once the bob is released, this gravitational force is able to act on it, thus moving it downwards towards its original hanging point. We can say therefore, that as it is released, the GPE is converted into Kinetic Energy (KE) ...read more.

Middle

Both the graph and the average table results show that the length of time the pendulum takes to do one complete period is affected by the time. As seen in the table, but more easily seen on the graph the time the pendulum takes to do one complete period increases as the length of the pendulum increases. On the graph each colour represents a different length of string and the lines of best fit are in blue. The lines of best fit go up in time for each length, clearly showing that the pendulum takes longer to complete a full period when the length of the pendulum is longer. This is also shown in the table. If you look down a column then the time increases as the length of the string increases. However the graph and the set of results in the tables show that mass does not affect the time it takes for a pendulum to complete a full oscillation. Although the lines of best fit go up in time for each length they are all almost completely horizontal. So as mass is on the x axis it shows that no matter what the mass the time it takes for the pendulum to complete a full period nearly always stays the same, as long as the length is the same. This can also be seen in the table. If you look across each row then the time stays roughly the same all the way across. ...read more.

Conclusion

Instead of timing how long it took for the pendulum to do one complete period for each mass and length, I would have set the pendulum off and counted how many complete periods the pendulum did before it stopped. By counting and not timing it reduces human error again and so making the results more accurate and reliable. However I still think the experiment is accurate and reliable enough to support my conclusion despite any anomalies I might have found. To extend the experiment and find additional relevant evidence I could choose any of the other variables, which I thought might affect the pendulum, listed in the plan, and see if any of these do prove to affect a pendulum. For example do exactly the same experiment that I have just done, but keep the mass and length the same and change the angle at which the pendulum is released. Then you could time how long it took for the pendulum to complete one full period and do this for different angles. By recording the results you would be able to see if the angle at which the pendulum is released does affect the time taken to do one complete period. Another variable you could change would be air friction, so you could keep the mass and length the same, but change the air friction. To do this you could do the experiment both inside and outside. Again by recording the results you could see if this variable does affect the pendulum. Robbie Maddison 10zc Mr Robinson Physics Coursework: The Pendulum ...read more.

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