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š” Where sound begins
Pluck a rubber band, blow a bansuri, strike a taal — every sound starts with something shaking back and forth. No shaking, no sound.
How is sound produced?
- Sound is produced by vibrations — the periodic to-and-fro motion (oscillations) of an object.
- As long as the object vibrates, sound is produced; when it stops, so does the sound.
- The vibrating object is called the source of the sound.
In this Activity, we will explore how a vibrating rubber band produces sound and stops producing it once the vibration stops.
- Stretch a rubber band across the open side of a cardboard box (Fig. 10.2).
- Pluck the band and listen — do you hear a sound? Watch it: is it vibrating?
- Wait till the band stops vibrating — do you still hear the sound?
- Change the tension and pluck again; notice how the sound changes.
What we observe
Sound is heard
only while the band vibrates
. Once the vibration stops, the sound stops — sound is produced by vibrations.
š§µ Threads of Curiosity
Gently touch your throat while you talk or sing — you feel vibrations! In humans, sound is produced by the vibration of the vocal cords , tightly stretched flaps inside the voice box (larynx). Some animals, like grasshoppers and crickets, rub their wings or legs to make sound.
