Transcript Speed of sound - Coosa High School

WAVE and SOUND
Sound Terminology
Amplitudeis the maximum distance
the particles in a wave
vibrate from their rest positions.
Frequency
- the number of waves
produced in a given time
Sound Terminology
Wave Velocity - is the speed with which a
wave crest passes by a particular point in
space
It is measured in meters/second.
Wave Velocity = Frequency  Wavelength
Speed of Sound
• Medium
air (20 C)
air (0 C)
water (25 C)
sea water
diamond
iron
copper
glass
velocity m/sec
343
331
1493
1533
12000
5130
3560
5640
Sound Terminology
Pitch
- description of how high or low
the sound seems to a person
Higher Pitch means Increased Wave Frequency
Tone: A sound of distinct pitch, quality, and
duration; a note.
. Loudnesshow loud or soft a sound is
perceived to be.
CLICK HERE:
Loudest Speakers
Analysis Question:
What is the relationship
between
PITCH AND WAVELENTH?
Sound Terminology
• Acoustics: the study of all mechanical
waves in gases, liquids, and solids
including vibration, sound, ultrasound and
infrasound.
• Decibel: ( dB) is used to measure sound
level, but it is also widely used in
electronics, signals and communication.
Loudness of Sound in Decibels
Sound
Loudness (dbs) Hearing
Damage
Average Home
40-50
Loud Music
90-100
After long
exposure
Rock Concert
115-120
Progressive
Jet Engine
120-170
Pain
Are Sound vibrations visible???
• http://www.kirotv.com/
videos/news/videowhat-doeswashingtons-loudestcar-stereo/vCM4g4/
Think, Pair and Share
Complete the following Hypothesis:
If you are exposed to sounds louder than 200 decibels, then
your internal organs most likely will
_____________________________________________ because
__________________________________________________.
Sounds and Mediums
• Waves must have medium in order for
sound to be heard
– Of the three mediums (gas, liquid, and solid)
sound waves travel the slowest through
gases, faster through liquids, and fastest
through solids.
– Temperature affects the speed of sound.
• http://www.ndted.org/EducationResources/HighSchool/Sound/te
mpandspeed.htm
Ultrasound
sound waves with frequencies above the
normal human range of hearing
Sounds in the range from 20-100kHz
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Infrasound
- sounds with frequencies below the
normal human range of hearing.
Sounds in the 20-200 Hz range
Obstetric Ultrasound
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Date the pregnancy (gestational age)
Confirm fetal viability (if it is living)
Determine placement of fetus, intrauterine vs ectopic
Check the location of placenta in relation to the cervix
Check for the number of fetuses (multiple pregnancy)
Check for major physical abnormalities
Assess fetal growth
Check for fetal movement and heartbeat.
Determine the sex of the baby
4 D Ultrasound Images
Animals In Utero
Other Uses of Ultrasound
• Medical
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Detecting blood-clots in arteries and veins
Eye scans
Any soft tissue scans (organs, skin, muscles, etc)
Biopsies
Break up kidney stones
Chemotherapy - delivery of medicines using high frequency
Jewelry Cleaning - UltraSonic
Humidifiers
Identification Badges
Sonar - in submarines and ships
Product testing – finds flaws in materials
Used in Horses to detect injuries
Used in Beef Industry to evaluate fat thickness, rib-eye
area and to improve breeding procedures
Ultrasound in Animals
• Echolocation (Echoes) - Sonar
– Using echoes for communication, navigation
and foraging
– Bats and Whales / Dolphin, Shrews, Cavedwelling birds, Tenrecs
– Humans use of echolocation
• Called “Perceptual Mobility”
• Blind persons
•Whales, elephants, hippopotamuses, rhinoceros, giraffes,
Okapi and alligators are known to use infrasound to
communicate over distances—up to hundreds of miles in
the case of whales.
•Tigers use low frequency growls to
paralyze their prey
•It has also been suggested that migrating birds use
naturally generated infrasound, from sources such as
turbulent airflow over mountain ranges, as a navigational
aid.
ANSWER THE FOLLOWING:
TRUE OR FALSE: SIGHT IS THE PRIMARY SENSE FOR ALL
ANIMALS
COMPLETE THE FOLLOWING STATEMENT:
SOME ANIMALS NEED INFRASOUND AND ULTRASOUND
BECAUSE
________________________________________________________
__________________________________________
HUMANS NORMALLY DON’T NEED INFRASOUND OR
ULTRASOUND BECAUSE ____________________________
EXPLAIN THE EVOLUTIONARY ADAVANTAGES OF INFRASOUND
AND ULTRASOUND.
Infrasound: Paranormal Activity
and Religious Activity
• Documentation of infrasound and ghost
activity
• Ghosts and spirits emit low
Frequency sound waves
• Extreme bass of Organ
music triggers spiritual
feelings or a feeling of a
person nearby or a
presence.
Infrasound and Other Mental and
Physical Effects
• Infrasound can cause fear, have a
negative effect on a person physically and
even cause death.
– Elevated blood pressure and heart rate,
nausea
– Release Endorphins leads to adrenaline
response
– Anxiety, coldness, tingling sensations,
sorrow, shivers down the spine
WARM UP 3/12
WEDNESDAY
Describe a situation where
CONSTRUCTIVE INTERFERENCE
would be necessary or beneficial.
Describe a situation where
DESTRUCTIVE INTERFERENCE
would be necessary or beneficial.
Interference
• The result of two or more sound
• Waves Overlapping
Interference
Constructive Examples
• Iridescence
– Bubbles
– Butterfly wing colors
• Musical Instruments
– Instruments harmonize
and become one sound
Destructive Examples
• Noise Cancelling
Headphones
– Pilots – decreases noise
from high decibel
environments
– Construction Workers
PITCH AND THE DOPPLER EFFECT
You are standing by the side of the road. A car horn blares as it comes
toward you and passes you at constant speed. The PITCH of the horn
that you hear
a. gets higher and higher as the source approaches and gets lower and lower
as the source recedes
b. stays at a constant high pitch as the source approaches and then drops to a
constant lower pitch as the source recedes
c. stays at the same constant pitch throughout the motion
d. maintains the same pitch except at the moment the source passes
e. varies too much to tell what the pitch is doing
DRAW A DIAGRAM TO EXPLAIN YOUR ANSWER
Doppler Effect
Change in the frequency of a sound
caused by the motion of either the
listener or the source of the sound.
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Sonic Booms
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If the source is moving as fast or faster
than the Speed of sound the sound waves
pile up into a shock wave called a sonic
boom.
Enormous energy
A sonic boom sounds very much like the
pressure wave from an explosion
The crack of a bull-whip is a small sonic
boom.
Sonic booms are
usually associated
with Space Shuttle
Landings or large
aircraft.
Resonance
the frequency of sound waves
exactly matches the natural frequency
of an object. A Forced Vibration.
An example of resonance: A motor that causes vibration in a
piece of furniture in another part of the same house.
These vibrations occur because the furniture has a natural
frequency equal to the frequency of the vibrations set up by
the motor.
Mythbusters Resonance
Bridge Video Clips
Mechanical Resonance can produce vibrations strong
enough to destroy the object in which they occur.
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For example, soldiers marching over a bridge can
cause extreme vibrations at the bridge's natural
frequency and shake it apart. For this reason, soldiers
break step to cross a bridge.
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In 1940 wind gusts at Puget Sound Narrows,
Tacoma, Washington, caused a suspension bridge to
vibrate at its natural frequency and the bridge
collapsed.
In Music, resonance is used to increase the intensity
(loudness) of a sound. The comparatively weak vibrations
produced at the end of an organ pipe, for example, cause a
column of air in the pipe to vibrate in resonance, thus greatly
increasing the loud-ness of the sound.
In humans, the vibrations of the vocal cords are reinforced
by resonant vibrations in the oral and nasal passages.
Video of Vocal Chords
Steven Tyler Vocal Chords
Can the human voice shatter glass????
Mythbusters Rock Star Singing
Kid Breaking Glass
• Everything has a Resonant Frequency
• the speed at which it will vibrate if bumped or otherwise
disturbed by some stimulus, such as a sound wave
• Glass wine goblets are especially resonant because of their
hollow tubular shape
• If a person sings the same tone as that ringing note, the
sound of the voice will vibrate the air molecules around the
glass at its resonant frequency, causing the glass to start
vibrating as well.
• If sung loudly enough, the glass will vibrate itself to
smithereens.
Resonance and the Singing
Glass
• The motion of your hand
Resonance
sets up a wave of
• Adding energy into the
vibration traveling
substance at its resonant
through the glass.
frequency will force it to
• The vibrations cause air
vibrate or resonate
molecules to vibrate at
• As your finger slides and
the same frequency.
sticks along the surface of the
• The vibrating air
rim, energy is added to the
molecules are the sound
glass molecules and causes
wave that you hear
them to resonate.
Glass Singing
Electrical Resonance
Electrical resonance
• is used to tune radios
and television sets.
• Tuning consists of
establishing a circuit with
a resonant frequency
equal to the assigned
frequency of the desired
station.
Magnetic Resonance Imaging
MRI
• Medical imaging using powerful magnets,
radio frequency and atoms in the body
– Used for more detailed images of the heart,
brain, etc. Used to detect cancers
– No Ionizing radiation (cancer causing)
Colors of Noise
• Different audio signals
– used in engineering, electronics and physics
• Each sounds different to the human ear
• Each has a different spectral reading
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White
Pink
Red (Brown)
Gray
Blue
Violet
Black
Green
White Noise
• White noise does not vibrate at one
specific frequency
• It covers a range of frequencies.
• Often used as sirens by the emergency
services
• It cuts through background noise and does
not echo so it is easier to perceive the
direction the vehicle is travelling.
White Noise Sound Machines
Link: White Noise Sound Machines Used to help Babies sleep may
be doing harm
STRUCTURE
PINNA
AUDITORY CANAL
FUNCTION
Outer part of the external ear. It amplifies sound by
funneling it from a large area into the narrower
auditory canal.
Carries sound waves to the tympanic membrane.
OSSICLES
Hammer: Malleus
Anvil: Incas
Stirrup: Stapes
TYMPANIC MEMBRANE
(EAR DRUM)
Tiny bones that amplify and carry sound in the middle
ear.
EUSTACHIAN TUBE
Air-filled tube of the middle ear that equalizes
pressure between the outer and middle ear.
Chamber at the base of the semicircular canals. Also
associated with equilibrium.
Fluid-filled structures that provide information
concerning equilibrium.
Coiled tube within the inner ear that receives sound
waves and converts them into nerve impulses.
VESTIBULAR NERVE
SEMI-CIRCULAR CANALS
COCHLEA
Receives sound waves.
HEARING LOSS TYPES
• CONDUCTIVE
– Sound doesn’t move correctly
through the ear drum, ear canal
or ossicles
– Sounds like ears are plugged
– Person may speak softly b/c
their voice seems loud to them
– Causes
• Earwax
• Punctured eardrum
• Fluid in the ear
• Genetic defect
• Infection
– Treatment
• Surgery
• Medicine
• Hearing Aid
• Cochlear Implant
• SENSORINEURAL
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Damage to the Cochlea or Nerves
90% of people with hearing loss
Gets worse over time
Some can hear, but can’t understand
what people are saying
– Causes
• Aging
• Infections
• Head Trauma
• Genetics
• Exposure to loud noises
• Fluid build-up
-Treatment: Usually can’t be treated
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Depends on the Specific Damage
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Hearing Aid
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Cochlear Implant
Otoscope: Instrument used to view the ear drum
Perforated Eardrum
Never use Q-tips!!
Ear Tubes Decrease Pressure in the Ear
Drainage is normal
after surgery
Hearing Aids
• Electronic Devices that amplify sounds
• Hair cells in the ear detect vibrations and convert to
nerve signals
• Not effective for everyone
• Only 1 in 5 people use due to embarrassment or financial
reasons
• Consists of
• a microphone
• amplifier
• receiver/ speaker
• battery
• Over 28 million people suffer from hearing loss
COCHLEAR IMPLANTS
Cochlear implants bypass damaged portions of the ear
and directly stimulate the auditory nerve.
VIDEOS AND ANIMATIONS
Cochlear Implants and Hearing Loss
Cochlear Implant: Girl Hears for the First Time
Hearing Frequency Test: EXTRA CREDIT!!!!
Julianna Wetmore: Treacher Collins Syndrome
INTERESTING FACT!!
The more intense a sound is, the louder
it will be. Normal sounds carry small
amounts of energy, but HUMAN ears
are very sensitive
IF we had enormous ears like Dumbo’s,
we could hear a sound delivering to this
area an energy of only one Trillionth of a
joule each second!
Since our ears are thousands of times
smaller, the energy our ears receive in a
second is thousands of times less.