For my coursework investigation I have been asked to investigate the effects on the swing of a pendulum. The effects that I thought most suitable are length of string, weight of mass and angle of release.

Diagram to show set up of my investigation

How I will conduct the investigation

In my investigation I will be recording the time it takes for the pendulum to make ten swings and then divide that number by ten.  I am using ten swings as it will be more accurate to compensate for human error and will give me an average.

How I will investigate the effects on a swing of a pendulum changing the angle of release

I will keep the length of string and weight of bob at a constant and change the angle of release each time I start a new session of swings on the pendulum. I will do this by measuring, recording and then changing the angle of release using a protractor.

How I will investigate the effects on a swing of a pendulum changing the length of the string

I will keep the weight of the bob and angle of release at a constant and change the length of the string each time I start a new session of swings on the pendulum. I will do this by measuring, recording and then changing the length of the string.

How I will investigate the effects on a swing of a pendulum changing the weight of the bob

I will keep the length of the string and angle of release at a constant and change the weight of the bob each time I start a new session of swings on the pendulum. I will do this by measuring, recording and then changing the weight of the bob.

My prediction

Change of the angle of release

I think that the time of the swing will stay constant as the angle of release is increased.  I think this because the weight and length is the same therefore it will not have longer to travel and it will have the same weight.

Change of the length of string

I think that the time of the swing will become faster as the length of the string is increased.  I think this because the further the weight is from the fulcrum the greater the turning effect of the force.

Change of the weight of bob

I think that the time of the swing will become longer as the weight of the bob is increased.  I think this because gravity pulls a higher mass faster than a lower mass.

Changing the Weight

Changing the angle of release

Changing the length of the string

Conclusion

I have found that the only effect that significantly alters the speed of a swing on the pendulum is the length of the string.  This shows that my prediction was wrong as I thought the angle of release would also change but I was correct that the length of the string would affect time.

This shows me that the moment of a force equals force multiplied by distance from fulcrum to line of action of the force