In a simple time of flight experiment, the speed of sound is observed to travel about 5% slower inside a corrugated irrigation pipe as compared with measurements conducted in open air. Although some theoretical understanding for this retardation is provided, the focus of this paper concerns how this finding might be incorporated into an undergraduate lab activity that challenges student understanding of error analysis and its significance. We propose an inquiry-based format, recently championed by others, wherein students are challenged to decide how to resolve their observation of a slower speed in a second round of investigations.

1.
N. G.
Holmes
and
C. E.
Wieman
, “
Introductory physics labs: We can do better
,”
Phys. Today
71
(
1
),
38
45
(
2018
).
2.
C.
Walsh
,
K. N.
Quinn
,
C.
Wieman
, and
N. G.
Holmes
, “
Quantifying critical thinking: Development and validation of the physics lab inventory of critical thinking
,”
Phys. Rev. Phys. Ed. Res.
15
,
010135
(
2019
).
3.
N. G.
Holmes
,
B.
Keep
, and
C. E.
Wieman
, “
Developing scientific decision making by structuring and supporting student agency
,”
Phys. Rev. Phys. Ed. Res.
16
,
010109
(
2020
).
4.
E. M.
Smith
,
M. M.
Stein
,
C.
Walsh
, and
N. G.
Holmes
, “
Direct measurement of the impact of teaching experimentation in physics labs
,”
Phys. Rev. X
10
,
011029
(
2020
).
5.
N. G.
Holmes
and
E. M.
Smith
, “
Operationalizing the AAPT learning goals for the lab
,”
Phys. Teach.
57
,
296
299
(
2019
).
6.
American Association of Physics Teachers
, AAPT Recommendations for the Undergraduate Physics Laboratory Curriculum (
2014
). <https://www.aapt.org/Resources/upload/LabGuidlinesDocument_EBendorsed_nov10.pdf>
7.

The corrugated pipe is made of high density polyethylene (HDPE) and can be found at most any home improvement store for less than 4 USD per meter.

8.
Wikipedia,
<https://en.wikipedia.org/wiki/Speed_of_sound>. The speed of sound varies linearly over temperature ranges from −80 to +50 °C and can be approximated as 331.4+0.606T, where T is in Celsius.
9.
J. W.
Elliot
, “
Corrugated pipe flow
,” in
Lecture Notes on the Mathematics of Acoustics
, edited by
M. C. M.
Wright
(
Imperial College Press
,
London
,
2005
).
10.
D.
Tanon
,
B. J. T.
Landry
,
S. P. C.
Belfroid
,
J. F. H.
Willems
,
G. C. J.
Hofmans
, and
A.
Hirschberg
, “
Whistling of a pipe system with multiple side branches: Comparison with corrugated pipes
,”
J. Sound Vibr.
329
,
1007
1024
(
2010
).
11.
G.
Nakiboglu
,
S. P. C.
Belfroid
,
G.
Golliard
, and
A.
Hirshberg
, “
On the whistling of corrugated pipes: Effect of pipe length and flow profile
,”
J. Fluid. Mech.
672
,
78
108
(
2011
).
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