OCR AS Physics

Revision Notes

1.2.11 Methods to Increase Accuracy

Methods to Increase Accuracy

  • The accuracy of an experiment can be increased by repeating measurements and using mean values
  • Methods seeking to reduce systematic errors result in increased accuracy
  • In order to reduce the uncertainty of results for an experiment some changes may need to be made to the method, such as:
    • Timing over multiple oscillations
    • Using a fiducial marker
    • Using a set square or plumb line

Using Multiple Oscillations

  • Uncertainty in a measurement of periodic time can be reduced by:
    • Measuring many oscillations to calculate the average time for one oscillation
    • Increasing the total time measured for multiple swings
  • It would be ideal to measure the time taken for the pendulum to complete 10 (or more) oscillations and divide this time by 10 to determine the time period of one oscillation

Complete Oscillation Pendulum, downloadable AS & A Level Physics revision notes

One complete oscillation of a pendulum

Fiducial Marker

  • A fiducial marker is a useful tool to act as a clear reference point, such as when measuring time period of a pendulum using a stopwatch
  • This improves the accuracy of a measurement of periodic time by:
    • Making timings by sighting the pendulum as it passes the fiducial marker
    • Sighting the pendulum as it passes the fiducial marker at its highest speed. The pendulum swings fastest at its lowest point and slowest at the top of each swing

Fiducial marker, downloadable AS & A Level Physics revision notes

A fiducial marker is used to mark the centre of the oscillation of the pendulum

Set Squares & Plumb Lines

  • A set square can be used to determine whether:
    • An object is vertical
    • Two objects are at right angles to each other
    • Two lines are parallel
  • A plumb line can be also be used to determine if a setup is vertically aligned accurately

Set square and plumb line, downloadable AS & A Level Physics revision notes

A plumb line and set square used to make sure the setup is completely vertical

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Katie has always been passionate about the sciences, and completed a degree in Astrophysics at Sheffield University. She decided that she wanted to inspire other young people, so moved to Bristol to complete a PGCE in Secondary Science. She particularly loves creating fun and absorbing materials to help students achieve their exam potential.

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