Physics AP - Speed of Sound in Air (#20)

Background:
To find the speed of sound use the wavelength (8) times by the
frequency (f), 8f = v. In this lab the wavelength of the wave is
equal to four times the length of the tube. This is because of nodes,
a place where there are no waves, and anti?nodes, where waves reach
their maximum amplitude. Nodes form where you switch mediums, for
instant go form air to a more dense substance like water, or where
destructive interference.  Destructive interference causes the waves
to cancel each other out; they are out of phase 180°. Anti-nodes form
at switching mediums form a dense to a less dense, and also in the
center of the space between nodes. According to this, a node will
form at the water in the tube, and an anti?node will form at the open
end of the tube.  

Problem:
Find the speed of sound through air by using a glass tube, three
tuning forks, and water. 

Procedure:
1. Measure diameter of tube.
2. Place glass tube into water with part of it sticking out.
3. Hit tuning fork against palm of hand.
4. Place tuning fork above tube, and adjust tube up and down until
   the note that is being played sounds the same as the note you
   heard from the tuning fork in.
5. Repeat step 3.
6. Record length of tube from the water to the end of the tube
   outside of the water and the frequency of the tuning fork being
   used.
7. Repeat steps 2-6 with the two other tuning forks.
8. Calculate the speed of sound in each case.  

Data:   
F        Lo       D       Ladj	  8       Vexp    Vaccepted
440      .191m    .15m    .1846m  .7784m  342m/s  343.6 m/s
480      .173     .15     .1776   .7104   341     343.66
493.9    .170     .15     .1746   .6984   345     343.66
523.2    .159     .15     .1646   .6544   342     343.66