Physics - Sound

Question 1

HOW IS SOUND MADE?

Answer 1

Vibrations or oscillations

Question 2

SOURCES OF VIBRATION:

Answer 2

-Vocal chords,
-strings on an instrument,
-lips when one plays the trumpet,
-reed on an oboe,
Cone in loudspeakers.

Question 3

WHICH PART OF THE EAR VIBRATES?

Answer 3

The eardrum

Question 4

HOW DOES SOUND TRAVEL FROM THE SOURCE TO OUR EARS?

Answer 4

-Vibration of source - eardrum vibrates,
-Above causes inner ear hairs to vibrate,
-Above causes generation of electrical signals,
+Electrical signals travel to nerves in brain - hearing.

Also, forces of vibrating air next to ear drum causes vibration

Question 5

LONGITUDINAL WAVE

Answer 5

Vibrations parallel to the flow of the sound energy. E.g. direction of sound from speaker, same as direction of air particle vibration from candle flame. see physics - sound inn photos

Question 6

THE EFFECT OF SOUND TRAVELING THROUGH AIR ON PARTICLES AND AIR PRESSURE:

Answer 6

PARTICLES: see photos physics - sound
0 Sound sent to ear - pushes and pulls air particles next to it, meaning air particle vibrate left and right,
0 Sound creates compressions (Air PARTICLES bunched together) and rarefactions (Air PARTICLES +spaced out),
0 Sound wave/ sound = longitudinal sound wave - air particles travel in same direction as sound waves.

AIR PRESSURE:
1 Sound creates compressions (Air PRESSURE ^ than normal) and rareFACTIONS (Air PRESSURE lower than normal)

Question 7

COMPRESSION

Answer 7

+Air particles bunched together,
+Region where air pressure is ^ than normal.

Question 8

RAREFACTION

Answer 8

_Air particles more spaced out,
_Air pressure lower than normal.

Question 9

SOUND TRAVELS AS A LONGITUDINAL WAVE

Answer 9

see photos physics- sound

Question 10

RECALL Qs AND As FROM THE BELL JAR EXPERIMENT:

Answer 10

see photos - physics- sound

Question 11

WHICH DOES SOUND TRAVEL FASTEST IN, SOLIDS, LIQUIDS OR GASES?

Answer 11

Hint:
hard wood - 4000 m/s
Aluminium - 5100 m/s
Iron and steel - 5000 m/s
Seawater - 1560 m/s
Water - 1440 m/s
H - 1300 m/s
He - 1005 m/s
Air - 331 m/s

Answer = solids, not how clearly you can hear it; but how fast.

Question 12

THE DENSER THE MEDIUM, THE SLOWER SOUND TRAVELS; TRUE OR FALSE?

Answer 12

False, the more dense the medium the faster sound travels, should have done true because I am reading this question a lot so will skim past it without real acknowledgement meaning I will believe above it true, this is just to keep you on your toes though.

Question 13

sound travels slowest in gases; true or false

Answer 13

True

Question 14

SOUND OF A SOLID IN A VACCUM IS…

Answer 14

…quieter than the sound of a solid not in a vaccum

Question 15

Sound waves cannot pass through a vaccum

Question 16

VACCUM

Answer 16

A region of space with no particles or atoms in it, e.g. space.

Question 17

CALCULATION OF THE SPEED OF SOUND, TELL US:

Answer 17

see photos physics- sound

Question 18

‘Mach 1’ = ?

Answer 18

Jet plane flies faster than the speed of sound (reasoning = sound waves cannot escape the nose of the jet). Normally leads to ‘sonic boom’.

Question 19

WHAT HAPPENS WHEN MACH 1 IS EXCEEDED?

Answer 19

‘sonic boom’ x2 occurs, very loud sounds. To fly above Mach 1 need to be over ocean - noise pollution.

Question 20

HOW TO CREATE AN ‘audible’ ECHO:

Answer 20

1) Need reflection of sound to come from a surface, hardsurface.
Smooth because:ensures all sound reflects back to observer along same line (sound scatters in all directions, observer hears multiple echoes without this).
Hard because:ensures most of the sound reflected not absorbed.

see physics- sound in photos, observe well use brain

Question 21

HOW DO YOU MEASURE THE SPEED OF SOUND USING ECHOES?

Answer 21

see photos in physics - sound

Question 22

USES OF ECHOES?!?!

Answer 22

1) echolocation e.g. dolphins, bat, humans.
2) sonar, e.g. image of sea floor.
3) length of a steel/aluminium/iron rod e.g. measure time it takes for each to reach back tot he start of the rod.
4) flaw detector, e.g. measure distance it takes to see how deep flaw is and compare to length of steel rod for accuracy and to see if there is a flaw in the first place.

Question 23

USEFUL SPEED EQUATION FORO ECHOES:

Answer 23

d = s t/2
DIVIDED BY TWO BECAUSE ECHOES ARE A MIMIC OF THE REAL SOUND SO THERE ARE 2 SOUNDS IN TOTAL.

see photos in physics - sound

Question 24

REVERBERATION:

Answer 24

When the echo time is <0.1s, brain can’t tell echo apart from first sound. Observer hears 1 smoothed-out sound.

Heard in a room with no absorbents e.g. sound-absorbing furniture.

Question 25

CAUSES OF REVERBERATION?

Answer 25

* Multiple echoes *see photos in physics - sound*

Question 26

FREQUENCY.

Answer 26

***NUMBER OF VIBRATIONS PER SECOND*** *see photos in physics - sound*

Question 27

AMPLITUDE

Answer 27

***HOW FAR THE VIBRATION MOVES FROM ITS REST POSITION, e.g. how far the cone on a loudspeaker moves from its resting position.*** *see photos in physics - sound*

Question 28

RANGE OF HUMAN HEARING

Answer 28

**Normal Hearing:** - hear up to 25dB to hear average garden birds at 6000Hz (roughly) **Mild Hearing Loss:** -hear up to 26-40dB to hear an average person speaking at 1000 Hz **Severe Hearing Loss:** - hear up to 61-80dB to hear a piano at 1000 Hz **Profound Hearing Loss:** -81+dB to hear a motorbike at 4000 pitch (Hz) ***Average human cannot hear above 20,000Hz or below 20Hz***

Question 29

HOW DO YOU MINIMISE NOISE-INDUCED HEARING LOSS?

Answer 29

-Limit exposure to loud sounds. ***Amount of time one should be exposed to varies to the amount of sound (dB) they are exposed to.*** *see photos in physics - sound*

Question 30

INTERPRET AND DRAW CRO WAVEFORMS:

Answer 30

*see photos in physics - sound*

Question 31

HOW NOISE-INDUCED HEARING LOSS AFFECTS ABILITY TO HEAR SOUNDS:

Answer 31

The worse hearing one has; the more dB (louder) they need to hear sounds. *see photos in physics - sound*

Question 32

HOW FREQUENCY IS RELATED TO PITCH

Answer 32

**Frequency of a vibration ^ = pitch of note ^** *Frequency of a vibration ^ = number of waves seen on the CRO increases.* X-axis is always time. *see photos in physics - sound*

Question 33

EFFECT OF AMPLITUDE ON LOUDNESS

Answer 33

Large amplitude waves = holds a lot of energy. **Large amplitude wave = sound wave is loud** ***A WAVE OF ZERO AMPLITUDE CARRIES NO ENERGY; A SOUND WAVE OF ZERO AMPLITUDE IS COMPLETELY QUIET- THERE IS NO WAVE*** the wave would not knock over a sandcastle ;) :0 *see photos in physics - sound*

Question 34

Break 🧋🚱🥛🥤🥤

Answer 34

If need more breaks click do not know, if less click completely know.