Vivian

__**Topic:**__ Sound and Waves __**Questions I have:**__ 1) Why do high pitched sound waves break glass? 2) Why are burps always low pitched? 3) Why are sound waves created from a tuning fork really bumpy?


 * __Background + Research:__**

Rumor has it that opera divas can shatter glass with their high pitched notes. Hm... is that true? I always see it happening in movies, but does it really happen in real life? Below is a link that answers this question. http://wiki.answers.com/Q/How_do_high_pitched_sound_waves_shatter_glass I am not going to do an experiment related to this because I guess this is more like common knowledge than an interesting thing to find out.

Humans burp naturally after eating a lot, or drinking soft drinks like coca cola. Why is that? Below is a link that answers this question. http://tellmewhyfacts.blogspot.com/2006/11/why-do-people-burp.html Now that I know why people burp, but why are burps always low pitched? I have never heard of a high pitched burp! Hiccups are high pitched, but not burps!


 * __How I tuning fork works__**

As a tuning fork vibrates, it causes molecules in the air to move. The molecules bump into other molecules nearby, causing them to move. This process continues from molecule to molecule. The resulte is a series of compressions and rarefactions that make up sound waves.


 * __My Experiment__**

I recorded the sound made from the middle C, E and G tuning forks. I then recorded a person whistling. After this, I noticed how sound waves of tuning forks are really bumby. Unlike the tuning forks, the sound wave of a whistle is really smooth and what I would call 'a perfect sound wave'. This part of the experiment was done with Audacity.

The second part of my experiment is to see if the sound wave of the middle C tuning fork I recorded was really 256Hertz/second. I used the wave equation to do this. See data below.


 * __Data__**

Wave Equation : wavelength / period, wavelength x frequency

__//Middle C tuning fork//__ 3.63975 - 3.63555 = 0.00395 <-- period Frequency = 1 / period 1 / 0.00395 = 253.2 Hertz / second

253.2 Hertz is actually pretty close to the actual frequency of middle C which is 256 Hertz per second.

__**Conclusion**__

Although I didn't get perfect middle C (256 Hertz per second) when I calculated the sound wave of the tuning fork, but 253.2 is pretty close. This is mostly because I rounded numbers up when I measured the distance of one cycle. There was inaccuracy.

When a source vibrates, it actually vibrates with many frequencies at the same time. Each of those frequencies produces a wave. Sound quality depends on the combination of different frequencies of sound wave. This is why the sound wave of a tuning fork is bumpy. It's because the bumpy sound wave give the tuning fork its special tone.

//The anatomy of wave://

 * **crest** - peak of a wave
 * **trough** - lowest point of a wave
 * **amplitude** - distance from rest to crest
 * **wavelength** - length of 1 complete wave cycle
 * **frequency** - how often te particles of the medium vibrate when a wave passes through the medium (1 Hertz = 1 vibration/second)
 * **period** - time for a particle on a medium to make one complete cycle

//Types of Waves://

 * **Longitudinal** - particles of the medium are displaced in a direction PARALLEL to the direction of energy transport (slinky)
 * **Transverse** - particles of the medium are displaced in a direction PERPENDICULAR to the direction of energy transport (rope)
 * **Mechanical** - wave that requires a medium through which to transpit energy
 * **Electromagnetic** - a wave of energy having a frequency within the electromagnetic spectrum and propagated as a periodic disturbance of the electromagnetic field when an electric charge oscillates or accelerates
 * **Pressure wave** - a wave consisting of a repeating pattern of high pressure and low pressure regions moving through a medium (e.g. sound wave)

//The speed of a wave://

 * **What are some of the factors that affect the speed of a mechanical/transverse wave?**
 * 1) The speed of a wave is only altered by alterations in the properties of te medium through which it travels. Amplitude, wavelength or frequency does not affect the speed of a wave.
 * **What is the wave equation? How is it similar/different from a stardard speed or velocity equation?**
 * 1) standard speed = distance/time
 * 2) wave equation (speed) = wavelength/period, wavelength x frequency