Sound

Question 1

what are echoes

Answer 1

Echoes = reflection of sound waves - i=r (angle of incidence = angle of reflection

Question 2

what is sonar

Answer 2

Sonar = Sound, Navigation and Ranging

Question 2

how do ships use echo sounding

Answer 2

How ships use echo sounding:
ships use echo sounding by sending a soundwave downwards into the ocean and recording the time taken for it to relfect off the ocean bed and come back the the ship, depending on the time taken, the ship can calculate the depth of the ocean

Question 3

how does refraction help in soudwaves

Answer 3

Sound waves can also be refracted - in some situations, it allows sound to be heard clearer - e.g. across water (pond)
How:

Question 4

how can heat help with refraction

Answer 4

Most sound waves travel in a straight line, but some travel up
If the temperature is right, the upward waves are refracted and so they curve downwards, so more sound waves are received and the sound heard is clearer and louder

Question 5

what is the range of human ear

Answer 5

Range of frequency for humans = 20-20,000 Hz
This range narrows as we get older