Sound properties and Uses

Question 1

What happens when sound travels across a boundary?

Answer 1

Its velocity and direction (refraction) can change

If velocity increases, wavelength increases, frequency stays the same

Question 2

What happens when a sound wave hits the boundary at 0° to the normal?

Answer 2

Wave will speed up but won’t change direction

Question 3

What is Ultrasound?

Answer 3

Sound of a frequency over 20,000 Hz

Has very small wavelength

Question 4

How do Doctors and Midwifes use Ultrasound?

Answer 4

A transmitter beams ultrasound waves into the Mother
Waves reflect from different boundaries
Machine calculates distances using time and velocity and uses distances to produce an image

Question 5

What systems use Ultrasound?

Answer 5

Echo-sounding

Sonar (Sound, Navigation and Ranging)

Question 6

What is Echo-sounding?

Answer 6

A process of finding distance using the time for the reflection of a pulse of sound

Question 7

What is Sonar?

Answer 7

A method of working out the distance to objects or navigating using sound