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💡 A pure note
A tuning fork gives an almost single, clean frequency — which is why scientists love it for sound experiments.
What is a tuning fork?
Tuning Fork
A U-shaped metal bar with a stem, struck on a pad to give a nearly single-frequency sound. Sides of the U are the prongs
- A U-shaped metal bar with a stem, usually of steel or aluminium.
- The two sides of the ‘U’ are called prongs (or tines).
- Struck on a soft pad, the prongs vibrate and produce a nearly single-frequency sound.
Activity 10.2 — Let us explore
In this Activity, we will explore how a vibrating tuning fork produces sound and disturbs a water surface.
Activity 10.2 - Tuning Fork
Step 1
Strike a tuning fork on a rubber pad
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Step 2
Bring it near your ear
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Step 3
Touch a water surface with a prong
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Ripples form and sound is heard - the prongs vibrate
- Strike one prong gently against a rubber pad (never a hard surface) and bring it near your ear.
- Gently touch a water surface with a vibrating prong (Fig. 10.4c).
- Repeat, bringing the prongs near your ear in different orientations.
What we observe
You hear the sound, and ripples form on the water — showing the prongs are indeed
vibrating
. Sound is produced by vibrating objects.
⏸▶ Pause and Ponder
- 1. Ways to produce sound: plucking a string, striking a metal object, blowing air in a pipe, tapping a membrane — all involve vibration.
- 2. Instruments and their vibrating parts: sitar/veena (strings), tabla/drum (membrane), bansuri/flute (air column), taal (metal body).
🧵 Threads of Curiosity
- What if your name were a tune instead of a word?
- Kongthong is a village near Shillong in Meghalaya.
- It is also known as the ‘Whistling Village’.
- Every person there has a tune-name, sung or whistled.
- The tradition is called Jingrwai Iawbei .
- It begins at birth, when a mother composes the tune.
✅ Test Yourself
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How is sound produced?
Show Answer
By the vibration of an object. -
What is a vibration?
Show Answer
The periodic to-and-fro motion (oscillation) of an object. -
What is a tuning fork made of, and what are its sides called?
Show Answer
Steel or aluminium; the two sides of the ‘U’ are the prongs (tines). -
What is the ‘source’ of a sound?
Show Answer
The object that produces the sound.
Important Definitions
- Tuning fork — a U-shaped metal bar that vibrates to give a nearly single-frequency sound.
- Prongs — the two arms of a tuning fork that vibrate when it is struck.
