PASCO WA-9612 RESONANCE TUBE - Manual (Page 12)

Resonance Tube 012-03541E
8
➂ Raise the frequency slowly until you find a new resonant frequency. Again measure and
record the frequency.
➃ Continue finding still higher resonant frequencies. Find at least five.
➄ Now close one end of the tube. You can either put the piston in the end of the tube, support-
ing the rod on some convenient object, or place an object, such as a book, against the end of
the tube.
➅ Repeat steps 2-4 for the closed tube, recording your readings in Table 1.2.
TABLE 1.1
Resonant Frequencies for an Open Tube
Frequencies
ν
ν/ν
0
ν
0
= --------
TABLE 1.2
Resonant Frequencies for a Closed Tube
Frequencies
ν
ν/ν
0
ν
0
= --------
Analysis
For each tube configuration (open and closed) divide each of your resonant frequencies (n)
by the lowest resonant frequency (n
0
) that you were able to find. Your results should give
you a series of whole numbers. Record this series for each tube configuration. If you do not
get a series of whole numbers, you may not have found the lowest resonant frequency for
the tube. If this is the case, try to use your results to determine what the lowest resonant
frequency would have been, had you been able to detect it.
Questions
Is the number series you determined the same for both closed and open tubes? Which tube
configuration gives a series of consecutive whole numbers? If you have already studied
standing wave patterns, try to explain your results in terms of the types of standing wave
patterns that are excited in each tube configuration. Is there a node or an antinode at a
closed end of the tube? Is there a node or an antinode at an open end of the tube?