Physics Pendulum... 19/24

To determine if the length of a pendulum affects its period, (T), and compare the theoretical value of (T) to the experimental value.

Background Information:
A simple pendulum is one that can be considered to be a point mass suspended from a string or rod of negligible mass. It is a resonant system with a single resonant frequency. For small amplitudes, the period of such a pendulum can be approximated by:


      Laws of a simple Pendulum
            ▪ The period of a simple pendulum of constant length is independent of its mass, size, shape or material.
            ▪ The period of a simple pendulum is independent of the amplitude of oscillation, provided it is small.
            ▪ The period of a pendulum is directly proportional to the square root of the length of the pendulum.
            ▪ The period of a simple pendulum is inversely proportional to the square root of acceleration due to gravity.

It is hypothesised that as the length of the pendulum increases, the period (T), will also increase. Providing there is a constant angle of release (or amplitude) as the length of pendulum increases, the distance travelled by the point of measurement ( or ‘bob’) will increase. Hence the period increases.


    - 3 Large nails
    - Large protractor
    - Tape measure
    - String 2m
    - 500g Mass (pendulum bob)
    - Stopwatch
    - Spirit Level and set square


  Independent Variable – The length of the string

  Dependent Variable     – The time it takes for the pendulum to oscillate

  Controlled Variables   – The mass of the bob
                                        – The amplitude
                                        – The string, changed in length
                    – Controlled environment


    1) A table was drawn that allowed for recordings of raw data – 3 trials of 6 independent variables.

    2) The equipment was set up as shown in the diagram...