Download sound waves - Coosa High School

WAVE and SOUND
Amplitudeis the maximum distance
the particles in a wave
vibrate from their rest positions.
Frequency
- the number of waves
produced in a given time
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
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
Pitch
- description of how high or low
the sound seems to a person
. Loudnesshow loud or soft a sound is
perceived to be.
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
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 location of fetus, intrauterine vs ectopic
Check the location of the 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.
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
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
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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Doppler Effect and 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.
A sonic boom sounds very much like the
pressure wave from an explosion
Resonance
the frequency of sound waves
exactly matches the natural frequency
of an object.
Suspension Bridges and Resonance
Bridge Video Clips
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)
How the ear works
animation
Cochlear Implants and Hearing Loss
Sound and Fury Debate over Cochlear Implants
Hearing Frequency Test