Energy and Change:
Sound

Sound is vibration or oscillation of particles. Sound needs matter (solid, liquid or gas) to travel through. Sound cannot pass through a vacuum. A person on the Moon would not be able to hear sounds as the Moon does not have a gaseous atmosphere for the sound to travel through.

Musical instruments produce regular sounds by controlled vibrations in the musical instruments. For example, when a piano is played, the vibration caused by the hammer striking the string passes to other parts of the piano and vibrates the air inside and around the piano.

Electrical energy can be transformed into sound and sound can be transformed into electrical energy. For example, when we turn on the radio, electrical energy is transformed into movement of the amplifier. This vibration of the diaphragm of the amplifier is passed through the air to our eardrum, which vibrates. The vibrations stimulate nerves that send electrical messages to the brain which we interpret as sound.

Sound

Links:
Sound energy Human senses A: Sight and sound

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