light and sound waves

Question 1

what are sound waves

Answer 1

mechanical waves- meaning they need a solid liquid or gas to travel through so they can’t travel through a vacuum
longitudinal

Question 2

what happens when sound waves go from air into a soild

Answer 2

they cause vibrations of the same frequency in the solid

Question 3

how do sound waves help us hear

Answer 3

they cause solid parts of the ear to vibrate and the brain converts these vibrations into what we hear

Question 4

what does higher frequency mean in sound waves

Answer 4

higher pitch

Question 5

what does greater amplitude mean in sound waves

Answer 5

louder sound

Question 6

what are the uses of sound waves

Answer 6

ultrasound

echo sounding

Question 7

what are ultra sound waves

Answer 7

waves that have a frequency above the range of human hearing

Question 8

what happens when ultrasound waves meet a boundary between two substances

Answer 8

they are partially reflected

Question 9

how is the distance to a boundary calculated using ultrasound

Answer 9

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

Question 10

what can ultrasound be used for

Answer 10

medical and industrial imaging

Question 11

what is an echo

Answer 11

a reflected sound wave

Question 12

how does echo sounding work

Answer 12

it uses high frequency sound waves to detect objects in deep water and to measure the depth of water

Question 13

what are P waves

Answer 13

longitudinal

travel through liquids and solids

Question 14

S- waves

Answer 14

transverse

only travel through solids

Question 15

how do seismic waves help to tell us about the structure of the earth

Answer 15

the way they travel can indicate the internal structure of the earth

Question 16

how do seismic waves travel through the earth and what does this tell us about the structure of the earth

Answer 16

• their paths curve showing us that there is a gradual change in the density of the mantle
• S - waves are not detected on the opposite side of the earth suggesting that the outer core must be liquid
• kinks in the paths of P waves travelling to the other side of the earth suggest a sudden change in the density of the material they are passing through
• The existence of shadow zones where no P waves are detected suggest the existence of a solid inner core