Waves and sound
Ripple tank
Measure frequency and wavelength, then check the wave speed.
v = fλ
Apparatus
- Ripple tank model
- Crest counter
- Wavelength scale
Method
- Set the frequency and the wavelength.
- Read the speed from v = fλ before you count.
- Count crests for 5.0 s. The count should be close to frequency × 5.
- Double the frequency and halve the wavelength. The speed should stay the same.
A real ripple tank uses water and a lamp. Keep the electrical supply dry.
Frequency
2Hz
Wavelength
0.5m
Speed
1m/s
Crests in 5 s
—
The cork bobs once per wave, and the counted frequency matches the setting.
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