PAG: Measuring Wave Properties (OCR GCSE Combined Science A (Gateway)): Revision Note

Exam code: J250

Katie M

Author

Katie M

Last updated

PAG: Measuring Wave Properties

Equipment List

5-1-6-pag-wave-properties-equipment
  • Resolution of measuring equipment:

    • Metre ruler = 1 mm

    • Stopwatch = 0.01 s

Aims of the Experiment

  • To measure frequency, wavelength and wave speed by observing water waves in a ripple tank

Variables

  • Independent variable = frequency, f

  • Dependent variable = wavelength, λ

  • Control variables:

    • Same depth of water

    • Same temperature of water

Method

Ripple Tank Wave Properties Apparatus, downloadable IGCSE & GCSE Physics revision notes

Set up of ripple tank to investigate wave properties

  1. Set up the apparatus as shown and fill the ripple tank with water to a depth of no more than 1 cm

  2. Turn on the power supply and the light source to produce a wave pattern on the screen

  3. The wavelength of the waves can be determined by using a ruler to measure the length of the screen and dividing this distance by the number of wavefronts

  4. The frequency can be determined by timing how long it takes for a given number of waves to pass a particular point and dividing the number of wavefronts by the time taken

  5. Record the frequency and wavelength in a table and repeat the measurements

  • An example of the data collection table is shown below:

Ripple Tank Example Data Collection Sheet, downloadable IGCSE & GCSE Physics revision notes

Analysis of Results

  • The speed of the waves can be determined using the equation:

Wave Speed = Frequency × Wavelength

v = fλ

  • Where:

    • v = wave speed in metres per second (m/s)

    • f = frequency in Hertz (Hz)

    • λ = wavelength in metres (m)

Evaluating the Experiment

Systematic Errors:

  • It can be difficult to identify the wavefronts while they are moving

    • Use a stroboscope (flashing light) matched to the same frequency of the waves, this will be indicated by the waves appearing to be stationary

    • The frequency can be read from the frequency setting of the stroboscope, and the wavelength will be easier to determine while the waves appear still

Random Errors:

  • To improve the accuracy of the wavelength measurement in the ripple tank:

    • Measure across a number of waves (e.g. 5 of them) and then divide the distance by the number of waves

  • To improve the accuracy of the frequency measurement in the ripple tank:

    • Measure across a longer time period (e.g. a minute) and then divide the number of waves by the time

Safety Considerations

  • Care should be taken when working with water and electricity in close proximity

    • Carelessness could lead to electric shock

  • Make sure to stand up during the whole experiment, to react quickly to any spills

  • No food or drink should be consumed near the experiment 

  • If using strobe lighting to see the wavefronts more clearly, ensure no one in the room has photosensitive epilepsy

👀 You've read 1 of your 5 free revision notes this week
An illustration of students holding their exam resultsUnlock more revision notes. It's free!

By signing up you agree to our Terms and Privacy Policy.

Already have an account? Log in

Did this page help you?

Katie M

Author: Katie M

Expertise: Physics Content Creator

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.

Download notes on PAG: Measuring Wave Properties