Sound in Solids and the Ear

Question 1

What happens if a sound wave hits a solid?

Answer 1

After being reflected many times, the sound is eventually absorbed,
When absorbed, the particles in the solid vibrate and heat up the solid

Question 2

What happens when a sound wave hits a microphone?

Answer 2

When the microphone absorbs the sound wave it produces a changing electrical signal

Question 3

How does your ear detect sound?

Answer 3

Outer ear (Pinna and Auditory Canal) gather sound waves and direct to ear drum which vibrates
Ear drum vibrations cause ossicles to amplify the vibrations and pass onto the inner ear through the oval window
Cochlea transmits the movements of Oval Window to small hairs
Hairs are attached to sound detecting cells that release chemical substances making nerves send a signal down the auditory nerve to the brain

Question 4

What is the Cochlea?

Answer 4

A fluid filled, spiral shaped structure in the inner ear that contains hairs which detect different frequencies of sound

Question 5

What is Natural Frequency?

Answer 5

The frequency at which an object oscillates if it is displaced

Question 6

What is an example of Natural Frequency?

Answer 6

If you hold a ruler on the edge of a desk, push it down, it vibrates with frequency depending on length of ruler hanging off desk

Question 7

What is Resonance?

Answer 7

The large amplitude oscillation that happens when you make something oscillate at it’s natural frequency

Question 8

Why do you only hear a particular range of frequencies?

Answer 8

The range of frequencies you hear depends of the range of length of hairs in your cochlea
The hairs resonate at different frequencies of sound