Waves Flashcards

1
Q

What type of wave is on the surface of water?

A

Transverse waves, particles in the water move up and down as a waves oases - the particles are not carried to the shore

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2
Q

How do transverse waves move?

A

The particles move up and down at right angles to the direction the wave is moving

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3
Q

What can sound waves also do?

A

Transfer energy

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4
Q

What type of waves are sound waves?

A

Longitudinal waves, particles in the material through which the wave is travelling move backwards and forwards as the wave passes

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5
Q

What type of waves do earthquakes and explosions produce?

A

Seismic waves, they travel through the earth.

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6
Q

What waves can push and pull solid rock material?

A

Longitudinal seismic waves

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7
Q

What waves can can move solid rock material up and down and side to side?

A

Transverse seismic waves

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8
Q

What are electromagnetic waves?

A

Light, radio waves, microwaves, they are transverse waves and do not need a medium (material) through which to travel

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9
Q

What is wave frequency and what is it measured in?

A

Frequency Is the number of waves passing a point each second, it’s measured in hertz (Hz)

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10
Q

For sound and light what does the frequency determine?

A

Sound - pitch

Light - colour

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11
Q

What is a period?

A

The length of time it takes one wave to pass a given point

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12
Q

What’s a wavelength?

A

If the distance from a point on one wave to a point on the same position on the next wave measured in meters

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13
Q

What’s an amplitude?

A

It’s the maximum distance of a point on the wave away from its rest position, measured in meters. The greater the amplitude of a sound wave, louder the sound

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14
Q

What is a velocity?

A

It is the speed of the wave in the direction it is travelling. Waves travel at different speeds in different materials

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15
Q

Where do you measure the amplitude?

A

The amplitude of a wave is from the middle to the top or bottom, not the distance between top and bottom

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16
Q

What can changes in frequencies, wavelengths or amplitude be used for?

A

Can be used to transfer information from one place to another. E.g when you listen to FM radio, the music is sent by variations in the frequency of the radio waves

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17
Q

Go to book and look at page 50 for wave speeds

A

Now

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18
Q

What does the speed of a wave depend on?

A

The medium through which its travelling

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19
Q

What speed does light always travel at?

A

300 000 000m/s in a vacuum, but it travels more slowly in glass or water.

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20
Q

What reduces when light goes from air into water?

A

The wavelength

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21
Q

How can you find the speed of sound?

A

By measuring the time it takes for a sound to travel a certain distance. For example, if you stand in front of a large wall you can measure the time it takes for an echo of a loud sound to reach you.

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22
Q

What can you use to calculate the speed of sound?

A

A Speed, time, distance equation

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23
Q

How can you measure the speed of waves on water?

A

Measure the time it takes for a wave to travel between two fixed points such as buoys. The speed can be calculated from the time and the distance between the points

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24
Q

Go to page 52 and 53 to look at the core practical

A

Now

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25
Q

Where do most waves travel but then where can they change direction to?

A

Outwards from their source in straight lines, however waves can change direction when they can move into a different medium

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26
Q

What is the change in direction called?

A

Refraction

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27
Q

When does refraction happen?

A

At the interface (boundary) between the two media

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28
Q

What is the line at right angles to the interface called?

A

The normal line

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29
Q

What does light travelling along the normal do?

A

It doesn’t change direction when it goes into a different medium

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30
Q

When do we see things?

A

We see things when light reflected from them reaches our eyes

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31
Q

Waves can travel through many different media but with different speeds

A

As light passes the interface between one medium and another it changes speed. This change in speed causes the direction of the light to change

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32
Q

What does the bend depend on?

A

How fast the light travels in the two media and the angle of the light hitting the interface. The greater the difference in speed between the two media, the more light is bent. The light bends towards the normal when it slows down

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33
Q

How can we use waves on water?

A

To help us understand what happens with light waves .

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34
Q

What does the speed of waves depend on?

A

How deep the water is

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35
Q

Hat do waves moving from deep water into shallow water do?

A

Slows down and changes direction

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36
Q

What do lines on Ray diagrams show?

A

The direction the wave is moving not the waves themselves

37
Q

Look at the diagram on page 55

A

Now

38
Q

What does reflected mean?

A

The wave ‘bounces’ off

39
Q

What does refracted mean?

A

The wave passes into the new material but changes the direction in which its travelling

40
Q

What does transmitted mean?

A

The wave passes through the material and is not absorbed or reflected

41
Q

What does absorbed mean?

A

The wave disappears as the energy it is carrying is transferred to the material

42
Q

What does light do with lighter coloured objects

A

The light reflects

43
Q

What do darker objects do with light?

A

It absorbs light

44
Q

What is light from light bulbs or the sun called? How is it made?

A

White light, it’s made up of a mixture of different frequencies of light

45
Q

What do we see different frequencies of light as?

A

Colours

46
Q

When do different colours in light change speed?

A

When it travels from air to glass

47
Q

How can sound waves be affected?

A

In the same way as light waves, we hear echoes when sound is reflected by a hard surface. Some materials absorb sound well and some transmit it well. Sound is also refracted when it goes into different materials, but this is much harder to observe

48
Q

In different materials what speeds do sound waves travel at?

A

Different speeds

49
Q

What is wave velocity equal to?

A

The frequency multiplied by the wavelength, so if the velocity changes, either the frequency or wavelength (or both) must change

50
Q

When we hear sounds at different pitches, what are our ears detecting?

A

The different frequencies of sound, (not wavelengths)

51
Q

When a sound wave enters a different material what changes?

A

The wavelength and the velocity, not the frequency

52
Q

What type of waves are sound waves?

A

Longitudinal waves

53
Q

When a sound wave reaches a solid what happens?

A

Some if the energy it is transferring is reflected and some transmitted through the solid or absorbed by it

54
Q

What does a sound wave cause? What happens?

A

Causes changes in pressure on the surface of a solid to vibrate and so the disturbance miss passes from air to the solid . The vibrations in the solid can be passed on both as longitudinal and transverse waves

55
Q

What do sea waves transfer to the shore?

A

Energy, when waves hit the land the energy is transferred to the land and can wear it away

56
Q

How do we deck sound waves?

A

Using our ears, the part of the ear on the outside of our heads helps us channel sound waves into our heads. The vibrations caused by the sound waves are passed on through various parts of the ear until they are detected and converted to electrical impulses that travel to the brain.

57
Q

Where do sound waves enter? (Ear)

A

The ear canal

58
Q

What is the eardrum?

A

A thin membrane, sound waves make it vibrate

59
Q

In the ear where are the vibrations from the eardrum passed onto?

A

On to tiny bones (ossicles) which amplify the vibrations (make them bigger)

60
Q

Where in the ear are the vibrations passed onto after the ossicles?

A

Passed onto the liquid inside the cochlea

61
Q

What do the tiny hairs inside the cochlea do to the vibrations?

A

Detects them and creates electrical signals called impulses

62
Q

In the ear where do the impulses travel?

A

Along neurones in the auditory nerve to reach the brain

63
Q

What is the cochlea and how does it work?

A

Is a coiled tube containing liquid. It can detect the different frequencies of sound reaching the ear. Human ears can detect sounds from 20Hz to 20000Hz

64
Q

In the cochlea what does the base do?

A

It’s thicker and stiffer and detects high frequencies

65
Q

In the cochlea what does the apex do?

A

It’s thinner and detects low frequencies

66
Q

What does the part of the membrane that vibrates depend on?

A

Depends on the frequency of the sound waves in the liquid inside the cochlea, as different thicknesses of the membrane vibrate at the best frequencies

67
Q

How many hair cells are along the membrane in the ear and what does it do?

A

Thousands, and they detect vibrations, each hair cell is connected to a neurone that sends impulses to the brain, the brain interprets signals from different neurones as different pitches of sound

68
Q

Go to page 59 and look at the diagram

A

Now

69
Q

what are sound waves with higher frequencies than 20 000Hz called?

A

Ultrasound

70
Q

How can animals such as dolphins and bass detect objects around them and what happens?

A

Using ultrasound waves, the ultrasound waves they make are reflected by things around them and animals listen for the echoes

71
Q

What piece of equipment is carried onto ships or submarines to find the depth of the sea or to detect fish?

A

Sonar equipment

72
Q

On ships how does sonar equipment work?

A

A loudspeaker on the ship emits a pulse of ultrasound. This spreads out through the water and some of it is reflected by the sea bed. A special microphone on the ship detects the echo and the sonar equipment measures the time between the sound being sent out and the echo returning.

73
Q

Go to page 60 and look at the equation

A

Now

74
Q

Apart from sound waves what can ultrasound also be used for?

A

To make images of things in the body, a common use is unborn babies so that directors can monitor how well the fetus is developing

75
Q

When a mother is having an ultrasound scan what is the gel used for and what is the probe used for?

A

Used to stop the ultrasound just reflecting from the skin, the probe emits and receives ultrasound waves

76
Q

What are sounds with a frequency less that 20Hz called?

A

Infrasound, they are too low for humans to hear

77
Q

What can infrasound a travel further than before they become to faint to detect?

A

Higher frequency sounds, animals such as elephants can hear infra sounds

78
Q

Which waves can natural eve rents such as volcanic eruptions and earthquakes create?

A

Infrasound waves as well as sounds that we can hear

79
Q

What are the vibrations such as earthquakes called?

A

Seismic waves, the energy released by an earthquake can travel through the earth as P waves or S waves

80
Q

Are P waves longitudinal or transverse?

A

Longitudinal

81
Q

Are S waves longitudinal waves or transverse waves?

A

Transverse

82
Q

What can seismic waves be detected by?

A

Seismometers

83
Q

What can longitudinal waves be transmitted through?

A

Solids liquids and gases

84
Q

What can transverse waves travel through?

A

Transverse waves need a medium to travel through so only solids

85
Q

Go to page 62 and 63 and look and the earth diagram and the last paragraph

A

Earth diagram

86
Q

What do scientists use information about the time the waves arrive in different places and the speed of the waves in different types of rock for?

A

To model the paths the waves have taken through the earth

87
Q

What does the place where the waves are detected depend on? And what is it called? (The earth)

A

Depends on where an earthquake occurs, but there is always a large area of the earth on the opposite side to the earthquake were no S waves are detected. This is called the S wave shadow zone

88
Q

When does the S wave shadow zone occur?

A

It occurs because part of the interior of the earth is liquid, there is also a band around the earth called the P wave shadow zone