? Library of Wonders   The Wonder of Sound

How does a microphone make sounds bigger?
When you speak into a microphone, you voice gets bigger. But how does it work? A microphone, or mic, is a device that changes sound waves that are carried by air into electric signals. Air inside the microphone transfers the incoming sound waves into electricity. This is how sound waves are transformed into electric signals. Once sound waves are made into electric signals, the sound can be made louder by changing the strength of the electric signals. The electric signals can also be passed along electric wires to places far away. The device that does this is a power amplifier, or power amp.

TVs, radios, and telephones also change sounds into electric signals. This is why you can listen to voices and sounds from very far away.