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Sound Chapter

  1. Oct 21, 2003 #1
    We need to write down why knowing the speed of life would be important to us personally. Can anyone come up with suggestions? I would appreciate it.

    I would also like to find experiments or information on how to measure the speed of sound. I would appreciate it if you provide me with experiments that are easy to do at home and don't need complicated equipement.

    I'll be waiting your responses.
    Thank you!:smile:
  2. jcsd
  3. Oct 21, 2003 #2
    Well if you live fast you die young, that's pretty important.

    I assume you meant the speed of light.

    For every material, there is a constant that determines the angle that light will refract through when it passes from air (or a vacuum) into that material. That constant is c and is usually written like this:

    aircwater, this would be the constant for light passing from air into water, I think that the constant is called the refractive index, and in the case of water it would take the value 1.33 (maybe). This means that the speed of light in water is the speed of light in air divided by 1.33.

    c also equals sin i / sin r where i is the angle of incidence and r is the angle of refraction.

    Unfortunaktely this is as far as I can take you for light, I can't think of any experiment to actually measure the speed of light. However I can tell you that it is approximately 2.997 * 10^8 m/s.

    For sound though, that is much simpler. For this you will need a stopwatch, a pair of symbols and a friend willing to walk as far down the street as possible.
    Your friend clashes the symbols together as hard as he can and when you see him do this, start the stopwatch. When you hear the sound stop the stopwatch. As bigger distance as possible is needed for this to make it more accurate, but you will also need to measure the distance between the two of you.
    Alternatively, if you had access to some microphones and some equipment, you could set it up so that when mic 1 detects a sound it starts a timer, then when mic 2 detects a sound it stops a timer. Place them a measured distance apart and have them both facing the same way. Stand directly in line with the two of them but closest to mic 1, then clap two wooden blocks together. This will give the effect of measuring the time taken for sound to travel from mic 1 to mic 2, then speed = distance/time.

    I hope this has helped you out for the sound, sorry about not being able to help you out so much for the light.
  4. Oct 22, 2003 #3
    Oh sorry, what I meant was the speed of sound, not speed of light, what a mistake.

    I'll be thankfull for further suggestions.
  5. Oct 22, 2003 #4
    Well if you go back and read my post, you'll find a little experiment for measuring the speed of sound that's easy to perform.

    Get a friend to stand a measured distance away, then have him clash two symbols together and time from when you see the symbols clash until you hear them.
    The use the equation speed = distance/time to find the speed of sound.
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