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Waves Lab

Physics · Cambridge O Level · Waves · Motion, frequency and wavelength

Follow a travelling disturbance and a single oscillating particle. Compare transverse and longitudinal waves and explore v = fλ.

Preview of Waves Lab

Free to explore. The interactive lab loads only when you start. No account or saved progress.

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Things to try

  1. Play the transverse wave. Follow the amber particle: does it travel right with the disturbance or oscillate around one position?
  2. Pause and Step through a period. Compare the selected particle in the medium with its displacement–time trace.
  3. Keep speed fixed and double frequency. Predict and measure the new wavelength and period.
  4. Switch to longitudinal. Find a compression and a rarefaction. Explain why maximum displacement is not the centre of a compression.
  5. Set amplitude to zero. Then try the longest wavelength: explain why a full wavelength no longer fits in the window.

Key ideas

  • A wave transfers a disturbance through a medium while its particles oscillate locally. This ideal model has no bulk particle drift.
  • Transverse oscillations are perpendicular to propagation; longitudinal oscillations are parallel. Compressions have closer particle spacing and rarefactions have wider spacing.
  • Wave speed equals frequency times wavelength: v = fλ. At fixed speed, increasing frequency decreases wavelength.
  • Period is the time for one oscillation: T = 1/f. Amplitude is maximum displacement from equilibrium.
  • The continuous sinusoidal wave travels right. Displayed phase loops at two periods; the finite drawing window is not a reflecting boundary.

Exam tip

Distinguish a snapshot of displacement against position from a particle displacement–time graph. Measure wavelength on the position graph and period on the time graph. Use consistent SI units in v = fλ.

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