Speed of sound and echoes

6.04

Is the speed of sound depended on the temperature of the air?

And does sound waves travel faster through hot air or cold air?

Yes it is depended on the temperature of the air.

Does sound waves travel faster through hot air or cold air?

Sound waves travel faster through hot air than though cold air.

Does speed of sound depend on the pressure of the air?

The speed of sound does not depend on the pressure of the air. If the atmospheric pressure changes, the speed of sound waves stays the same.

Is the speed of sound different through different materials?

Yes it is different through different materials.

How fast or slow does the the sound waves travel through solids, liquids and gases?

Sound waves travel faster through liquids than through gases, and fastest of all through solids.

What is the equation for speed of sound?

Speed of sound = distance travelled : time taken

How can speed of sound be measured (experiment)?

A sound is made by hitting a metal block or plate with a hammer. When the control unit receives a pulse of sound from microphone A, it starts the clock. When it receives a pulse from microphone B, it stops it.

Does the temperature of the air have an effect on the speed of sound waves?

Yes it does.

Explain refraction of sound waves during night time, when the ground cools quickly, and air layers near the ground become colder than those above.

Sound waves travel more slowly through this colder air. As a result, waves leaving the ground tend to bend back towards it, instead of spreading upwards. A bending effect like this, caused by change in speed, is called refraction

What is an echo and echo time?

Reflected sound a short time after the original sound. The time it takes is the echo time.

What is the formula for speed of sound, for an echo?

Speed of sound = 2x distance to the wall : echo time

Why is the distance to the wall, timed with two in the speed of sound, for an echo?

Because the sound is sent to the wall, then reflected back, and then we hear the echo.

What is an echo-sounder?

Measures the depth og water under a boat. Send pulses of sound waves toward the sea bend and measures the echo time. Longer time → deeper water

What is an electronic tape-measure?

Like an echo-sounder. A surveyor measures the distance between two walls.

What is a radar?

Echo-sounding principle but with microwaves instead of sound waves. It detects the positions of aircraft by measuring the “echo times” of microwave pulses reflected from them.