Physics · 3.1 General properties of waves · Ripple tank
Ripple Tank. Make waves.
Generate water waves and explore wavelength, frequency and speed (v = fλ). Switch the source to a point (circular waves) or a bar (plane waves) and add a gap to watch diffraction.
0625 Topic 3.1 — Wave properties
v = fλ · diffraction
Variables
6.0
3.0
3.0
Live readouts
Frequency f
6.0 Hz
Wavelength λ
3.0 cm
Wave speed v = fλ
18.0 cm/s
Period T = 1/f
0.17 s
Wave speed v = fλ. Diffraction is greatest when the gap width is comparable to the wavelength.
📋 Method (Cambridge ATP procedure)
- Set up a ripple tank with a vibrating bar (plane waves) or dipper (circular waves) and a stroboscope/lamp to "freeze" the pattern.
- Measure the wavelength by measuring across several wavefronts and dividing.
- Read the frequency from the motor; calculate the wave speed v = fλ.
- Place barriers with a gap to observe diffraction; vary the gap width relative to λ.
Observations: waves slow and bend over shallow regions; diffraction spreads waves most when the gap ≈ λ.
⚠ Precautions
- Measure across many wavelengths and divide, to reduce uncertainty.
- Use a strobe to freeze the motion for clear measurements.
- Keep the water depth uniform unless investigating refraction.
🎯 Syllabus reference (0625)
- 3.1 General properties of waves — define wavelength, frequency, wavefront, amplitude and period; recall and use v = fλ; describe the use of a ripple tank to show reflection, refraction and diffraction; describe how diffraction depends on the gap width relative to the wavelength.