Sound Waves

Sound Waves

What causes sound?

vibrations in the air from voices or objects create sound

If a tree falls in the forest and no one is around to hear it does it make a sound?

Check THIS out

Sound Waves are produced when vibrations from an object (like a speaker) collide with molecules in the air and pass energy to them.

Sound waves are compressional waves

Sound waves can travel through other mediums, like water.

They cannot travel through empty space.

If a person screams in empty space, do they make a sound?

Speed of SoundDepends on.........

1.  Medium (gas, liquid, types of solids)2.  Temperature - sound travels faster through warm air

How we hear sounds:

1.  Compressional waves enter ear2.  Eardrum transfers waves to 3 tiny bones - all serve to AMPLIFY the sound3.  Waves are converted to nerve impulses by the cochlea4.  Brain decodes and interprets that information

Is hearing and listening the same thing?

Anatomy Attack!

Can you name the parts of the ear  (# 4, 6, 7, 9 )?

What is INTENSITY?  = amount of energy that flows through a certain area, we perceive it as loudness

                 Intensity decreases with distance

Decibel Scale  (dB)  - measures sound intensity

 Sounds over 120 dB may cause pain and hearing damage

Pitch is related to frequency of sound waves

                   do, re , mi, fa, so, la, ti, do

Compare a high pitch to a low pitch:

                         http://www.flashmusicgames.com/

A healthy human ear can hear at frequencies                                                 from 20 Hz to 20,000 Hz

As you grow older, hairs in your cochlea become damaged, which results in hearing loss.   

The mosquito ring tone capitalizes on this by providing teenagers a ring that adults cannot hear.

Test it at   http://www.jimmyr.com/blog/hearingloss.html

On the ear, circle or shade the  COCHLEA. Draw and arrow to the eardrum Place a check mark next to the nerves that connect to the brain.

Analyzing Charts

What is the frequency (HZ) and Decibal (dB) level of a crying baby?   _________

A vacuum? _______

A motorcycle? ______

A teleophone? ______

A water faucet? _____

A dog bark? _______

Most people can't hear sound above 20,000 Hz 

                 - these are called ultrasonic waves

Subsonic waves have frequencies below 20 Hz

 You might not hear them, but you can feel them "rumble"

How do dog whistles work?

Dogs can hear up to 35,000 Hz.   This is beyond the range of human hearing

Test it at http://www.jimmyr.com/blog/hearingloss.html

1.  Which 2 animals have the largest hearing range? ______________2.  Which animal can hear the highest frequency sounds? ______3.  What range of hearing does a fish have? __________4.  Which animal has the smallest range of hearing? _______5.  The range of a rodent's hearing is similar to that of a __________

ULTRASONIC WAVES  - frequencies above 20,000 Hz

SUBSONIC WAVES - frequencies below 20 Hz

Ultrasonic Liposuction?     New fad or does it work?

Advertisement ....

Thanks to ultrasonic waves (approximately 40 kHz) excess fat pockets are removed without any bleeding or pain. The ultrasonic waves cause the release of water from the fatty storage areas.......

Discuss.....

Sonic boom created as this jet breaks the sound barrier.

A sonic boom is the sound associated with the shock waves created by an object traveling through the air faster than the speed of sound. 

Sonic booms generate enormous amounts of sound energy, sounding much like an explosion. 

Youtube Video on Sonic Boom

1.  Light travels  [ faster / slower ] than sound.2.  Supersonic travel breaks the [ light / sound ] barrier.3.  The shockwave begins at the [ wing / nose ] of the jet.4.  Humans can produce a sonic boom using a [ whip / horn ].

Mythbusters Sonic Boom  ~10 minutes

What is the Doppler Effect

Moving objects that have sound change pitch depending on their direction and speed - this is called the Doppler Effect

Doppler Effect Video 

1.  The Doppler Effect occurs when a source of sound or light       [ moves / changes frequency ].2.  The high pitch sound of a car horn turns into a       [ low / higher ] pitch when the car passes.3.  The  [ blue / red ] shift is evidence the universe is expanding.

What is Music?Sounds produced in a deliberate pattern

Instruments produce sounds of different frequencies.

Itunes top 10?    Guess what songs are on the list this week?

*Check Your Guesses Here

Frequencies of guitar strings depend on thickness, length and how tightly it's stretched.

Sound is amplified by resonance, instruments have a component that make the sound louder

Types of Instruments

1.  Strings

       violin, cello, guitar

Strings produce notes, hollow chamber (resonater) amplifies sound

Stretching the strings changes the pitch - something you can try with a rubber band

2.  Brass and Woodwinds

        Examples:  flute, trumpets, clarinets

A woodwind instrument is a musical instrument where player blows air against a sharp edge or through a reed, causing the air within its resonator to vibrate. 

Most are made of wood, but can also be made of brass or other metals. 

What is this instrument?

saxophone

3.  Percussion

shaken or struck to produce air vibrations

Examples:  

        drums, triangles

See Drum Kit wiki for samples of drum beats.

Drum Line Video

What is this instrument? xylophone

How Well Do You Know Instruments?

TRUMPET

TUBA

BONGOS

FLUTE

What is Acoustics ?            the study of sound

The design of concert halls can change the way music sounds due to reflection and absorption of sound waves

A scientist who works in the field of acoustics is an acoustician while someone working in the field of acoustics technology may be called an acoustical engineer.

What is Audiology?          =  the study of hearingAn audiologist is a health-care professional specializing in diagnosing and treating and monitoring disorders of the auditory a system portions of the ear.  These disorders may cause hearing and balance problems/

Audiologists can dispense hearing aids and recommend and  cochlear implants.

What is Echolocation? animals use sound to identify and track prey and navigate environment

Bats and Dolphins use echolocation 

What does "NAVIGATE" mean?

What is Ultrasound Imaging?Ultrasound waves are directed at a body, the waves reflect off organs and produce signals that are sent to a monitor. The monitor produces an imageThe image produced is called a SONOGRAM

What is an Ultrasound Technician ?also called Diagnostic Medical Sonographer 

work in  laboratories or hospitals where they capture the images of the inside of a human body

Many schools offer 1-2 year programs to earn your degree.

Average Salary is $60,000 per year, that's about $30.00 per hour.    See Ultrasound Technician for more info

Using cornstarch and the right frequency of sound - you can make a......  CORN STARCH MONSTER

QUIZ TIME!

Name of Quiz:  Sound

1. Sound travels faster in [ warm / cold ] air. 2.  The bones of the ear serve to ______________ the sound.3.  Sound moves through air by colliding with                                              [ molecules / energy ].    4.  Sound moving through air is a                   [ transverse / compressional ] wave.5. Sound intensity is measured in ____________

6.  Sounds waves with frequencies below 20 Hz are called [ ultrasonic / subsonic ]

7.  Name an organism that uses echolocation: ___________

8.  The image produced by an ultrasound is called a __________________________ 9.  What do you call a person who diagnoses and treats hearing problems? ____________________

10.  Give one example of a percussion instrument.