**Part B - Problem: How do you measure
the velocity of sound using Resonance?**

1.
Measure the air temperature in
the area of the experiment.

2. Predict the length of the tube where resonance
will occur.

a.
Calculate the velocity of sound using the temperature method.

This velocity of sound is the theoretical value.

V_{T} = 330 m/sec.+ (.6 m/sec.^{ }^{0}C x T)

b.
Calculate the wavelength of the sound.

Since
V = f x *l *then
* l =* V** ÷** f

c.
Calculate the length of the column.

Column Length = *l*** ÷** 4

3. Measure the length of the tube where
resonance will occur.

a. Clamp
the 5.00-cm diameter plastic tube in a vertical position on a ring stand.

b. Place a
container filled with water to within approximately 2-cm. of the top of the
container.

c. Strike
the tuning fork on the rubber mat provided causing it to vibrate. The number
stamped on the tuning fork (480, 512), is the frequency (f) of the sound.

d. Hold
the vibrating tuning fork over the tube as close to the tube as possible.
Adjust the position of the tube in the water by raising it or lowering it until
the sound from the vibrating tuning fork is intensified. This is the point at
which resonance occurs. Clamp the tube so an accurate measurement can be made.

e. Measure
the length of the air column in the tube (in meters) from the surface of the
water to the top of the tube, (L). The wavelength (*l*) of the sound is equal to four times the length of the air
column.

Remember: When a vibrating tuning fork is in 'down' position, the
sound wave travels down the tube, reflect off the water, and returns to the
tuning fork, just as it reaches the 'up' position. The reflected sound reinforces the sound made by the tuning fork,
making it seem louder. The sound has
gone down the length of the tube and back; or 2L, in half of a wavelength. The
length of the tube is therefore one-forth the wavelength. To determine the
wavelength of the sound produced multiply the length of the tube by four. This
relationship can be expressed as:

*l* = 4
x L (Record this value in meters.)

4. The velocity of sound is equal to the product
of the wavelength and frequency. V_{E} = f x *l*. This velocity of sound
will be considered the experimental value.

5. Compute error/percentage of error
using the above values of V_{E} and V_{T, }and record
them. If your value for the percentage
of error is more than **10%**, look
closely for errors, and repeat the experiment.

6. Repeat
steps 1- 5, using a tuning fork with a different frequency, (512).