Sound

Question 1

What causes sound?

Answer 1

Sound is made when an object vibrates

Question 2

How does sound travel through the air?

Answer 2

Longitudinal waves in a series of compression (particles close) and rarefactions (particles far apart)

Question 3

What happens to sound in a vacuum?

Answer 3

Sound cannot travel in a vacuum.

Question 4

How do you work out the speed of sound?

Answer 4

distance (m) divided by time (s)

Question 5

What inaccuracies can occur when measuring speed of sound and how can they be minimised?

Answer 5

Inaccurate distance measurement, wind (with and against), timing (more than 1 person), unlevel ground

Question 6

What happens when a sound wave meets a hard flat surface.

Answer 6

It is reflected back of the surface, ECHO.

Question 7

What is the speed of sound in water?

Answer 7

1500 m/s

Question 8

Ship sends out a sound wave and it gets back after 1 sec. (i) How long did the sound take to hit the bottom (ii) How far does the sound travel in that time? (iii) How deep is the sea?

Answer 8

(i) 0.5 s (ii) 1500 m (iii) 750 m

Question 9

How does ear work?

Answer 9

1&2. Sound waves are collected by the pinna or earlobe.

3. The sound wave then along the ear canal.
4. The sound waves bump up against the eardrum.
   causing it to vibrates.
5. The vibration moves tiny bones (ossicles) in the middle ear which amplify vibrations.
6. These bones carry vibrations into the inner ear to a fluid-filled tube called the cochlea which turns them into electrical signals.
   The fluid inside the cochlea vibrates a series of tiny hairs called cilia, which are attached to auditory nerves.
   9.The movement of these cilia stimulates the nerve cells, and they send signals to the brain via the auditory nerve.
   The brain processes these signals into the sounds we hear

Question 10

How can you study sound waves?

Answer 10

(i) a loudspeaker converts signals into sound waves (ii) signal generater produces different types of signals (converts longitudinal to transverse) (iii) oscilloscope shows wave patterns and allows us to see sound waves

Question 11

describe a sound wave

Answer 11

Amplitude (A) is height of peak/depth of trough. Higher A, louder sound.

Wavelength is linked to frequency (f) measured in metres. Frequency is neumber of waves per second and is measured in hertz (Hz). Long wavelength = lower pitch = lower frequency

Question 12

Function of Eardrum

Answer 12

When sound waves reach the eardrum it vibrates

Question 13

Function of ossicles

Answer 13

consists of 3 small bones called the Hammer, Anvil and stirrup. these bones help make vibrations larger.

Question 14

function of oval window

Answer 14

Smaller area than eardrum, passes bigger vibrations to the cochlea.

Question 15

function of cochlea

Answer 15

shaped like a snails shell, filled with liquid, vibrations effect the cochlea which effect the nerves which sends messages to the brain.

Question 16

Range of frequency a person can hear is called? Give values as well as name.

Answer 16

hearing range for young person: 20 - 20000Hz (20 kHz)

upper limit decreases with age

Question 17

5 ear problems

Answer 17

wax in the ear, perforated eardrum, earache, tinnitus, limited movement in ossicles

Question 18

Cause and cure of wax in ear

Answer 18

overactive gland - syringe the ear

Question 19

Cause and cure of perforated eardrum

Answer 19

very loud noises e.g. explosion - small holes cure themselves, large holes need skin grafts

Question 20

Cause and cure of earache

Answer 20

infection - antibiotics

Question 21

Cause and cure of tinnitus

Answer 21

regular loud noise - avoid loud noise

Question 22

Cause and cure of limited movement of ossicles

Answer 22

age - hearing aid