Sound waves, uses and hearing.

What are sound waves?

Mechanical waves and longitudinal.

What do mechanical waves need?

A solid, liquid or gas to travel through.

Where can't mechanical waves travel?

Through a vacuum.

What's longitudinal?

The oscillations of particles in the medium are parallel to the direction of energy transfer.

What happens when sound waves go from air into a solid?

They cause vibrations of the same frequency in the solid.

What do ultrasound waves have?

A frequency above the range of human hearing.

What can ultrasound waves always be?

Partially reflected when they meet a boundary between 2 substances.

What can the distance to a boundary be found?

By timing how long it takes for an ultrasound reflection to come back to a detector.

How can the distance of a boundary be used?

For medical and industrial imaging.

What's an echo?

A reflected sound wave.

What do echo sounding uses?

High frequency sounds waves to detect objects in deep water and to measure the depth of water.

What can sound waves cause?

Solid parts of the ear (ear drum) to vibrate.

What does the brain convert these vibrations?

Into what we hear, but only over a limited frequency range.

How high is the frequency range?

20Hz to 20kHz.

What would happen if there was a higher frequency?

There would be a higher pitch.

What would happen if there was a greater amplitude?

There would be a louder sound.