Question: What lengths of a closed air column will resonate in response to a tuning fork of a known frequency?

Hypothesis: That the length of the closed air column will have a direct and proportional relation ship with the wavelength.

Materials: 80cm plastic pipe, large graduated cylinder, two tuning forks (512 and 1029), meter stick, thermometer.

Procedure: – Place pipe into cylinder, fill cylinder as close to top as possible with water

• sound tuning fork and hold over mouth of pipe, move pipe slowly out of water and listen for first resonant sound,
• use meter stick to measure length of the air column for first resonant point
• Continue to raise pipe finding and measuring other points of resonance
• Repeats steps 2 through 4 with a tuning fork of a higher frequency
• Record air temperature of room

Analysis:

B) The speed of sound at the air temperature we recorded was 344.39 m/s at 21 degrees Celsius.

C) The wavelength of the first tuning fork (512Hz) was 0.67m and the wavelength of the second tuning fork (1029Hz) was 0.33m.

D) That if you multiplied the Length of the air column by the Wavelength you came up with ¼ of the length of the air column.

E) That if you multiplied the Length of the air column by the Wavelength you came up with ¾ of the length of the air column.

F) As a general rule the resonant wavelengths for a closed air column are ¼ the wavelength for the first ¾ of the wavelength for the second and 5/4 of wavelength for the third.

H) Sources of error in this investigation is that the human ear is not the most accurate measure of resonance also since there were many tuning forks being rung in one area and they could have interfered either destructively or constructively. These errors could be solved by having only one tuning fork in one room and also having the same person listen for the resonance each time.