Changing+the+sound

Changing the Sound There are many ways to change sound. Many of these are closely related to the other topics of sound. This is because to change the sound something else must be altered.

Wavelength~from crest to crest The wavelength of sound is directly related to the frequency As the wavelength gets shorter the frequency gets higher and when the wavelength gets longer the frequency gets lower

Mediums ~ substance through which a wave travels Different mediums cause sound to travel at a different speed. For example sound travels at the speed of 331 m/s in air and 972 m/s in helium. Helium is a lot less dense than air, thus its faster traveling. Because of this when a person inhales helium from the balloon their voice sounds higher. The sound is traveling at a faster speed creating a higher frequency. The pitch does not actually change, despite the higher sound to the human ear. So basically the frequency goes up and so does your voice. Its also related to the wavelength.

Octaves An octave is the interval between 2 points, where the frequency at the first point is half that of the second. //(70////o////F, 21////o////C)// //(ft)// || 17.92 || 9.03 || 4.52 || 2.26 || 1.129 || 0.56 || 0.28 || 0.14 || //(70////o////F, 21////o////C)// //(m)// || 5.46 || 2.75 || 1.38 || 0.69 || 0.34 || 0.17 || 0.085 || 0.043 || A musical tone is 8 full tones above or below another tone, with twice or half as many vibrations per second as the other tone. . http://www.engineeringtoolbox.com/sound-frequency-wavelength-d_56.html media type="file" key="naglec-11_EmilyOctave.mp3" width="240" height="20" http://hyperphysics.phy-astr.gsu.edu/hbase/sound/souspe.html#c5
 * Octave || 1 || 2 || 3 || 4 || 5 || 6 || 7 || 8 ||
 * Frequency //(Hz)// || 63 || 125 || 250 || 500 || 1K || 2K || 4K || 8K ||
 * Wavelength in air
 * Wavelength in air

media type="file" key="Helium.mov" width="300" height="300"

Doppler Effect ~ a change in the frequency with which waves (as of sound or light) from a given source reach an observer when the source and the observer are in motion with respect to each other so that the frequency increases or decreases according to the speed at which the distance is decreasing or increasing ~ http://www.merriam-webster.com/dictionary/doppler%20effect

The Doppler Effect ties into changing the sound because as an object moves towards a person, the frequency will seem to go up and as it drives away it will seem to be going down.Therefore as a fire truck is coming towards you, the siren it is producing, is seemingly getting higher in pitch because the wavelength is getting shorter and vice versa.



Vacuums ~ For how a vacuum effects the pitch of a sound, click here. The reason the sound gets harder and harder to hear is not necessarily because it is being "changed." Because the air is being removed, the sound molecules don't have anything to travel through. This causes a person to not be able to hear the noise. Because the sound is technically traveling through "nothing" the frequency and pitch goes down.

http://www.physlink.com/education/askexperts/ae26.cfm