Intermediate 1 Physics - PowerPoint PPT Presentation

Loading...

PPT – Intermediate 1 Physics PowerPoint presentation | free to download - id: 740087-MzY4O



Loading


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation
Title:

Intermediate 1 Physics

Description:

Title: General Last modified by: Fife Council Created Date: 1/1/1904 12:00:00 AM Document presentation format: On-screen Show Other titles: Times New Roman Arial ... – PowerPoint PPT presentation

Number of Views:21
Avg rating:3.0/5.0
Slides: 42
Provided by: orgu1165
Category:

less

Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: Intermediate 1 Physics


1
Intermediate 1 Physics
  • Sound and Music
  • Sound Waves
  • Speed of Sound
  • Using Sound
  • Amplified Sound

2
Intermediate 1 Physics
  • Sound and Music

Sound Waves
3
Sound Waves
  • Vibrations
  • Musical instruments produce sound when part of
    the instrument v _ _ _ _ _ _ _
  • A guitar string vibrates when it is plucked.

vibrates.
4
Vibrations
  • 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 _ _ _ _ _ _ .

air
waves
vibrate.
5
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
6
Frequency
  • F _ _ _ _ _ _ _ _
  • number of waves produced in one second.

Frequency
7
Frequency
  • A whistle produces a h _ _ _ _ _
    frequency sound than a vibrating drum.
  • The whistle has a much higher p _ _ _ _ .

higher
pitch
The higher the pitch means the higher the f _
_ _ _ _ _ _ _
frequency
8
Detecting Sound
  • S _ _ _ _ can be taken in by a microphone
    and a trace displayed on an oscilloscope.

Sound
9
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
10
Loud and quiet
11
Loud and quiet
  • A soft/quiet sound transfers l _ _ _
    energy so the oscilloscope trace will have a s _
    _ _ _ amplitude

less
small
12
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
13
High and Low Frequency
  • If the frequency is doubled, we say that sound B
    is an o _ _ _ _ _ higher than sound A.

octave
frequency 256 512 1024 (Hz) one
octave t _ _ octaves
two
14
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
15
Changing the Note
  • S _ _ _ _ strings produce a higher
    frequency than long strings.
  • T _ _ _ _ strings produce a higher
    frequency than slack strings.

Short
Tight
16
Changing the Note
  • 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.

length
higher
17
Intermediate 1 Physics
  • Sound and Music

Speed of Sound
18
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  
19
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
20
Speed of Sound Apparatus
different
21
Speed of Sound
  • 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.

starts
stops
metre
repeated
22
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
23
Intermediate 1 Physics
  • Sound and Music

Using Sound
24
Using Sound
  • Sound can travel through s _ _ _ _ _ ,
    liquids and g _ _ _ _ .

solids,
gases.
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
25
Using Sound
  • 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.

sounds
older
Some animals can detect higher frequency sounds
than h _ _ _ _ _ .
humans.
26
Using Sound - Ultrasound
  • 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.

upper
baby
image
27
Using Sound - Ultrasound
  • 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.

sonar
echo
fish
28
Sound Levels
  • The sound level of a noise means how l_ _ _
    it is.
  • The sound level varies depending on the source of
    the sound.

loud
Sound level is measured in d _ _ _ _ _ _
_ (dB).
decibels
29
Sound Levels
  • 130 J _ _ engine at 50 metres
  • 100 Pneumatic d _ _ _ _
  • 70 Rush hour t _ _ _ _ _ _
  • 0 S _ _ _ _ _ _

Jet
drill
Sound l _ _ _ _ (dB)
traffic
level
Silence
30
Sound Levels
  • 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.

noise
damage
volume
31
Intermediate 1 Physics
  • Sound and Music

Amplified Sound
32
Amplified Sound
  • 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.

listen
signal
33
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
34
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.
electrical
  • An electronic system of 3 parts is used to
    amplify the
  • s _ _ _ _ given out by the announcer

signal
35
Amplified Sound
Part of the system Function
m _ _ _ _ _ _ _ _ _ converts sound into an e _ _ _ _ _ _ _ _ _ signal
a _ _ _ _ _ _ _ _ makes the electrical signal s _ _ _ _ _ _ _ (bigger amplitude)
l _ _ _ _ _ _ _ _ _ _ converts the electrical signal back to s _ _ _ _
microphone
electrical
amplifier
stronger
loudspeaker
sound
36
Voltage Gain
  • The performances of different amplifiers can be
    compared by finding the gain of the amplifier.

37
Voltage Gain
  • Example
  • Find the voltage gain of the following amplifier.

38
Voltage Gain
  • 400

N.B. Voltage gain is just a number. It has no
u _ _ _ .
unit
39
Playback
  • 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.
  •  

voice
skull
ears
air
40
Playback
  • 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
    _ _ _ _ .

high
laser
noise.
41
Intermediate 1 Physics
  • Sound and Music

End of Unit
About PowerShow.com