1.13 Sound Waves & Hearing

Question 1

What are sound waves called by?

Answer 1

Vibrating objects

Question 2

What are sound waves?

Answer 2

Vibrations that pass through the molecules of a medium

Question 3

Are sound waves transverse or longitudinal waves?

Answer 3

Longitudinal

Question 4

How are the vibrations passed through the surrounding medium?

Answer 4

These vibrations are passed through the surrounding medium as a series of compressions and rarefractions

Question 5

What is meant by the compressions of vibrations?

Answer 5

Regions where the vibrating particles are closest together

Question 6

What is meant by the rarefractions of vibrations?

Answer 6

Regions where the particles are furthest apart

Question 7

How does a sound wave travel through a solid?

Answer 7

When the sound wave hits a solid object, the air particles hitting the object (the pressure) causes the particles in the solid to move back and forth (vibrate). These particles hit the next particles in line and so on - passing the sound wave through the object as a series of vibrations. As this happens over and over again, the sound wave is transmitted through the material.

Question 8

Do sound waves travel faster in more densely packed materials or less dense?

Answer 8

More densely packed materials

Question 9

Why do sound waves travel faster in more densely packed materials?

Answer 9

A higher density leads to more elasticity in the medium and hence the ease by which compression and rarefaction can take place.

Question 10

Do the wavelength of sound waves get longer or shorter when it speeds up?

Answer 10

Longer

Question 11

Do the wavelength of sound waves get longer or shorter when it slows down?

Answer 11

Shorter

Question 12

What are sound waves reflected by?

Answer 12

Hard flat surfaces

Question 13

What are echoes?

Answer 13

Reflected sound waves

Question 14

Why can’t sound waves travel in space?

Answer 14

It is mostly a vacuum so there are no particles to move or vibrate

Question 15

The ___________ of sound doesn’t change when it passes from one medium to another

Answer 15

frequency

Question 16

What 3 things can sound be?

Answer 16

• Absorbed
• Refracted
• Reflected

Question 17

What are ossicles in the ear?

Answer 17

A group of 3 small bones

Question 18

Describe how human hearing works

Answer 18

Sound waves that reach your eardrum cause it to vibrate. These vibrations are passed on to tiny bones in your ear called ossicles, through the semi-circular canals and to the cochlea. The cochlea turns these vibrations into electrical signals which get sent to your brain. The brain interprets the signals as sounds of different pitches and volumes, depending on their frequency and intensity. A higher frequency sound wave has a higher pitch. Human hearing (audition) is limited by the size and shape of our eardrum, and the structures of all the parts within the ear that vibrate to transmit the sound wave

Question 19

When the sound waves reach the cochlea, what happens next?

Answer 19

The cochlea turns these vibrations into electrical signals which get sent to your brain

Question 20

What does the brain do after the sound waves get sent to it?

Answer 20

The brain interprets the signals as sounds of different pitches and volumes, depending on their frequency and intensity. A higher frequency sound wave has a higher pitch

Question 21

What is another word for human hearing?

Answer 21

Audition

Question 22

What is human hearing (audition) limited by?

Answer 22

The size and shape of our eardrum, and the structure of all the parts within the ear that vibrate to transmit the sound wave

Question 23

What do the ossicles only work over?

Answer 23

A limited frequency range

Question 24

What does a limited frequency range in the ossicles mean for humans?

Answer 24

Humans cant hear very low-pitched or very high-pitched sounds.

Question 25

What range of frequencies do the ossicles in the ear transmit the most efficiently?

Answer 25

1kHz to 3kHz

Question 26

What range of frequencies can young people usually hear?

Answer 26

20Hz up to 20 000Hz

Question 27

What happens to the range of frequencies you can hear as you age?

Answer 27

The upper limit decreases, and sounds may need to be louder for you to hear them. This is mainly due to wear and tear of the cochlea or auditory nerve

Question 28

Why does the upper limit of the frequency you can hear decrease as you get older?

Answer 28

This is mainly due to wear and tear of the cochlea or auditory nerve

Question 29

What happens when sound waves travel from a less dense medium, to a more dense medium?

Answer 29

Their speed increases

Question 30

The role of the ear drum is to:

Answer 30

Transmit the vibrations of the sound wave to the ossicles

Question 31

The role of the auditory nerve is to:

Answer 31

Transmit the electrical signals from the cochlea to the brain

Question 32

The range of human hearing is approximately ___ Hz to 20,000 Hz

Answer 32

20

Question 33

The role of the cochlea is to:

Answer 33

Convert the vibrations into electrical signals