Class 11 Physics simulations · Waves

Resonance tube: speed of sound

Hold a vibrating tuning fork over a tube whose air column is set by a water level. Find the first and second resonance.

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What to notice

The sound becomes suddenly loud only at certain air-column lengths; the second resonance is about three times the first.

Key relation

L₁ + e = λ/4, L₂ + e = 3λ/4 ⇒ v = 2f (L₂ − L₁)

Try this

Find the first resonance, then lower the water to find the second. Is L₂ ≈ 3L₁? Why not exactly?

What you can change

• Tuning fork: choose 512 Hz, 480 Hz, 426.7 Hz, 384 Hz, 341.3 Hz, 320 Hz, 288 Hz
• Air column length L: 3 to 95 cm
• Room temperature: 0 to 40 °C

More in Waves

• Beats: two notes, one pulsing sound
• Doppler effect
• Open and closed organ pipes
• Pulse reflection at a boundary
• Ripple tank: two-source interference
• Sonometer: frequency and length
• Standing waves on a string
• Wave speed on a stretched rope
• Superposition of two waves
• Travelling wave

See all Class 11 Physics simulations or every Physica simulation.