Chapter 1 - Measurements


Describe an experiment to show how the period of pendulum can be determined

  • The simple pendulum is made to oscillate at a small angle.
  • When the oscillation is steady, the time taken for 20 oscillations is measured using a stopwatch.
  • The measurement is repeated and the average is calculated.
  • The period of the pendulum is given by average time for 20 oscillations divided by 20.

State the precautions you would take for the experiment.

  • Ensure that the oscillation is steady before starting to time.
  • Ensure that the angular displacement of the bob is less than 10 degrees.


Describe how you would obtain experimentally accurate values for internal (external) diameter of a thick metal pipe.

  • Use internal (external) jaws of vernier calipers to measure the internal (external) diameters of the pipe at three different positions.
  • Take the average values of the measurements.

Why is there a need to obtain the average of several readings?

  • To reduce random errors (the positive errors and negative errors will cancel out)