Sound Page

Sound is created when the air around us gets pushed quickly (compressed) and then the push stops. This air compression (compression = longitudinal wave) produces what scientists call a sound wave. Our ears can detect that wave and through the ear's eardrum, some small bones, and some nerves, tells our brain that a sound was just heard. Our brain can determine quickly (less than a second) all kinds of different sounds. Notice how just very small differences in the sound is enough for you to determine differences. Fine, Find, factual, actual, etc.

The creation and propagation of sound waves are often demonstrated in class through the use of a tuning fork. A tuning fork is a metal object consisting of two tines capable of vibrating if struck by a rubber hammer or mallet. As the tines of the tuning forks vibrate back and forth, they begin to disturb surrounding air molecules. These disturbances are passed on to adjacent air molecules by the mechanism of particle interaction. The motion of the disturbance, originating at the tines of the tuning fork and traveling through the medium (in this case, air) is what is referred to as a sound wave. The generation and propagation of a sound wave is demonstrated in the animation below.

The sound of our voice seems to be made louder by humming into a kazoo because the kazoo resonates or vibrates with the sound of your voice. Your voice is a complex sound wave that contains lots of different sounds all put together so that it sounds like one sound. Scientists call the different sounds harmonics, and all those harmonics together is what makes your voice sound different than someone else's.

Not all the harmonics get amplified the same amount, so a kazoo changes the way your voice actually sounds. When you hum a tune into the kazoo, you get a completely different sound. Some people call this music, some call this noise.

We, as humans, have created many more sounds. Some of these sounds are what we would call music and the music is created in lots of different ways. Many hundreds of years ago, people found that certain things, such as a metal wire, when plucked, produced a pleasant sound. Over the years the people created many musical instruments from that simple sound.

          Read more:

http://www.measure.demon.co.uk/docs/Theory.html

http://www.cpo.com/CPOCatalog/SW/sw_sci.htm

http://www.smm.org/sound/discuss/libbysound.htm

http://www.stemnet.nf.ca/~yliu/acoustics.html

http://rustam.uwp.edu/GWWM/sound_waves.html

http://www.glenbrook.k12.il.us/gbssci/phys/Class/sound/u11l1a.html 

http://www.erichusby.com/9lesson1a.htm 

Intro to sound  

Doppler Effect Applet   http://www.sciencejoywagon.com/explrsci/dswmedia/soundwav.htm 

Another Doppler Effect Applet http://lectureonline.cl.msu.edu/~mmp/applist/doppler/d.htm 

Car horn doppler sound http://www.kettering.edu/~drussell/Demos/doppler/carhorn.wav 

A commonly used example is a train. When a train is approaching, the whistle has a higher pitch than normal. You can hear the change in pitch as the train passes. The same is true with sirens on police cars and the engines of race cars.

Think of sound waves as pulses emitted at regular intervals. Imagine that each time you take a step, you emit a pulse. Each pulse in front of you would be a step closer than if you were standing still and each pulse behind you would be a step further apart. In other words, the frequency of the pulses in front of you is higher than normal and the frequency of the pulses behind you is lower than normal. 

Source: http://www.windows.ucar.edu/tour/link=/earth/Atmosphere/tornado/doppler_effect.html&edu=mid

Many more lessons on waves: http://www.sciencejoywagon.com/physicszone/lesson/09waves/default.htm

Acoustics -- The science of sounds, teaching their nature, phenomena, and laws.

Reverberation -- Multiple echoes or reflections; in ultrasonography, an artifactual image caused by delay of an echo which has been reflected back and forward again before returning to the transducer.

Tongue -- The tongue is usually muscular, mobile, and free at one extremity, and in man other mammals is the principal organ of , aids in the prehension of food, in swallowing, and in modifying the voice as in speech

Vocal cords -- Two small bands of muscle within the larynx. They vibrate to produce the voice.

Larynx -- voice box.

Trachea -- The windpipe. A fibrocartilaginous tube lined with mucous membrane passing from the larynx to the bronchi.

Lungs -- The lungs are a pair of breathing organs located with the chest which remove carbon dioxide from and bring oxygen to the blood. There is a right and left lung.

Great presentation with pictures or the inner ear bones http://www.ear-anatomy.com/overview.htm 

Ear Diagram Quiz http://www.rcs.rome.ga.us/hargett/anatomy/nervous/erdiqz.htm 

Ear Diagram and Function  http://www.geocities.com/thmshelp/ear.html

An AWESOME flash demonstration of how the ear works! http://www.hearingcenteronline.com/ear2.shtml