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Intermediate 1 Physics . Sound and Music. Sound Waves. Speed of Sound. Using Sound. Amplified Sound. Intermediate 1 Physics . Sound and Music. Sound Waves. Sound Waves. Vibrations Musical instruments produce sound when part of the instrument v _ _ _ _ _ _ _

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intermediate 1 physics

Intermediate 1 Physics

Sound and Music

  • Sound Waves
  • Speed of Sound
  • Using Sound
  • Amplified Sound

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intermediate 1 physics1

Intermediate 1 Physics

Sound and Music

Sound Waves

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sound waves
Sound Waves

Vibrations

Musical instruments produce sound when part of the instrument v _ _ _ _ _ _ _

A guitar string vibrates when it is plucked.

vibrates.

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vibrations
Vibrations

air

A trumpet blasts out sound when the a _ _ inside it vibrates

Energy is transferred from the vibrating object to the listener by sound w _ _ _ _ which travel through the air. These sound waves make the air v _ _ _ _ _ _ .

waves

vibrate.

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frequency
Frequency

Each note or sound has a frequency which is measured in h _ _ _ _ (Hz).

A tuning f _ _ _ has the frequency engraved on it.

This vibrating fork will produce 256 vibrations every s _ _ _ _ _ .

This means that 256 sound w _ _ _ _ are produced in one second.

hertz

fork

second.

waves

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frequency1
Frequency

F _ _ _ _ _ _ _ _

= number of waves produced in one second.

Frequency

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frequency2
Frequency

higher

A whistle produces a h _ _ _ _ _ frequency sound than a vibrating drum.

The whistle has a much higher p _ _ _ _ .

pitch

The higher the pitch means the higher the f _ _ _ _ _ _ _ _

frequency

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detecting sound
Detecting Sound

Sound

S _ _ _ _ can be taken in by a microphone and a trace displayed on an oscilloscope.

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loud and quiet
Loud and quiet

A loud sound transfers more e _ _ _ _ _ so the oscilloscope trace will have a l _ _ _ _ amplitude. The amplitude of a wave is the distance from the m _ _ _ _ _ of the wave to the top or bottom of the wave.

energy

large

middle

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loud and quiet1
Loud and quiet

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loud and quiet2
Loud and quiet

less

A soft/quiet sound transfers l _ _ _ energy so the oscilloscope trace will have a s _ _ _ _ amplitude

small

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high and low frequency
High and Low Frequency

The effect of changing the frequency of a note can be seen on the oscilloscope screen.

Sound _ has a higher frequency than sound _ .

B

A

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high and low frequency1
High and Low Frequency

octave

If the frequency is doubled, we say that sound B is an o _ _ _ _ _ higher than sound A.

frequency: 256 512 1024

(Hz)

one octave

t _ _ octaves

two

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changing the note
Changing the Note

A musician tunes a guitar by making the string t _ _ _ _ _ _ or looser.

While playing the guitar, the note is changed by altering the l _ _ _ _ _ of string which vibrates.

tighter

length

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changing the note1
Changing the Note
  • S _ _ _ _ strings produce a higher frequency than long strings.
  • T _ _ _ _ strings produce a higher frequency than slack strings.

Short

Tight

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changing the note2
Changing the Note

length

An organ produces a variety of musical notes which depend on the l _ _ _ _ _ of the air column which vibrates. The shorter pipes have the shorter air columns which produce the h _ _ _ _ _ frequency notes.

higher

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intermediate 1 physics2

Intermediate 1 Physics

Sound and Music

Speed

of

Sound

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speed of sound
Speed of Sound

During a thunderstorm, the lightning flash is seen a short time b _ _ _ _ _ the roll of thunder is heard. This is due to the fact that l _ _ _ _ travels much faster than sound through the air.

between

light

In air: Speed of light = 300 000 000 m/s

Speed of sound = 340 m/s

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calculating the speed of sound
Calculating the Speed of Sound

In a laboratory the speed of sound can be calculated using the formula below.

(meaning; speed equals distance d _ _ _ _ _ _ by time)

divided

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speed of sound apparatus
Speed of Sound : Apparatus

different

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speed of sound1
Speed of Sound

starts

A loud sound is made. As the sound reaches microphone A, the timer s _ _ _ _ _ .

When the sound waves reach microphone B, the timer s _ _ _ _ . The distance between the microphones is measured with a m _ _ _ _ stick.

The experiment can be r _ _ _ _ _ _ _ to calculate a more accurate, average result.

stops

metre

repeated

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speed of sound2
Speed of Sound

Example:

Recorded times: 0.0030 s, 0.0029 s, 0.0031 s, 0.0027 s, 0.0029 s

Average time = 0.0146/5 = s

0.0029

Distance travelled = 1 metre

Speed = distance/time

= 1.0/0.0029

= m/s

344.8

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intermediate 1 physics3

Intermediate 1 Physics

Sound and Music

Using Sound

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using sound
Using Sound

solids,

gases.

Sound can travel through s _ _ _ _ _ , liquids and g _ _ _ _ .

The only thing that sound cannot pass through is a v _ _ _ _ _ .

vacuum.

A vacuum is an e _ _ _ _ space, so there are no particles to pass on the vibrations.

empty

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using sound1
Using Sound

sounds

When listening to music, you hear

s _ _ _ _ _ with a wide range of frequencies. We can detect sounds that range from about 20 hertz to

20 000 hertz. As we get o _ _ _ _ , the upper limit gradually falls to about 15 000 hertz.

older

Some animals can detect higher frequency sounds than h _ _ _ _ _ .

humans.

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using sound ultrasound
Using Sound - Ultrasound

upper

Sound beyond the u _ _ _ _ limit of human hearing (20 000 Hz) is called ultrasound.

Ultrasound can be used in hospitals to scan the b _ _ _ in the mother's womb.

This can be used by a computer to produce an i _ _ _ _ of the baby on a screen.

baby

image

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using sound ultrasound1
Using Sound - Ultrasound

sonar

A system called s _ _ _ _ is used by fisherman at sea.

The ultrasound signal is transmitted towards the sea bed and an e _ _ _ is detected.

Shoals of f _ _ _ are located by this method.

echo

fish

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sound levels
Sound Levels

loud

The sound level of a noise means how l_ _ _ it is.

The sound level varies depending on the source of the sound.

Sound level is measured in

d _ _ _ _ _ _ _ (dB).

decibels

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sound levels1
Sound Levels

Jet

130 J _ _ engine at 50 metres

100 Pneumatic d _ _ _ _

70 Rush hour t _ _ _ _ _ _

0 S _ _ _ _ _ _

drill

Sound

l _ _ _ _

(dB)

traffic

level

Silence

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sound levels2
Sound Levels

noise

When sound levels rise to unacceptable levels, the problem is described as n _ _ _ _ pollution.

There are many sources of noise pollution, such as aircraft noise or pneumatic drills. Exposure to high sound levels over a long time can d _ _ _ _ _

our hearing. Listening through stereo headphones will produce a harmful effect if the v _ _ _ _ _ is turned to maximum.

damage

volume

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intermediate 1 physics4

Intermediate 1 Physics

Sound and Music

Amplified Sound

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amplified sound
Amplified Sound

listen

A stereo system can be used to l _ _ _ _ _ to a compact disc (CD) or a radio programme. No matter what function is selected, the signal passes through an amplifier which turns a small amplitude electrical s _ _ _ _ _ into a higher amplitude one.

signal

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amplified sound1
Amplified Sound

Only the amplitude of the signal is changed. The frequency does n _ _ change.

not

When announcements are made at airports and stations, the message has to be changed from sound into

e _ _ _ _ _ _ _ _ _ signals and back to sound.

electrical

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amplified sound2
Amplified Sound

When announcements are made at airports and stations, the message has to be changed from sound into

e _ _ _ _ _ _ _ _ _ signals and back to sound.

An electronic system of 3 parts is used to amplify the

s _ _ _ _ given out by the announcer

electrical

signal

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amplified sound3
Amplified Sound

microphone

electrical

amplifier

stronger

loudspeaker

sound

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voltage gain
Voltage Gain

The performances of different amplifiers can be compared by finding the gain of the amplifier.

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voltage gain1
Voltage Gain

Example:

Find the voltage gain of the following amplifier.

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voltage gain2
Voltage Gain

= 400

N.B. Voltage gain is just a number.

It has no u _ _ _ .

unit

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playback
Playback

voice

A recording of your own v _ _ _ _ will sound a bit strange when it is played back from a cassette.

This is because we normally hear our own voice by:

vibrations of bones in our s _ _ _ _ and

vibrations in the air being detected by our e _ _ _

When we listen to a recording of our own voice we hear it by:

vibrations in the a _ _ being detected by our ears only.

skull

ears

air

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playback1
Playback

high

A CD (compact disc) is a source of h _ _ _ quality sound. As the CD spins inside the CD player, light from a l _ _ _ _ reflects off the CD. There is no wear and tear of the disc surface and there is very little background n _ _ _ _ .

laser

noise.

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intermediate 1 physics5

Intermediate 1 Physics

Sound and Music

End of Unit

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