After finding Moloney and McGarvey's1 modified adiabatic compression apparatus, I decided to insert this experiment into my physical chemistry laboratory at the last minute, replacing a problematic experiment. With insufficient time to build the apparatus, we placed a bottle between two thick textbooks and compressed it with a third textbook forced down from above. We discovered that approximately one in three trials exhibited a damped pressure oscillation after compression, as shown in Fig. 1 below, making it difficult to determine the true peak pressure. We discarded these trials and used only those without oscillation. I subsequently have had time to build a version of Moloney and McGarvin's apparatus. Using this apparatus, my students and I have recently performed numerous adiabatic compression trials with three different gases, with very few instances of oscillation.

Topics
Adiabatic compression apparatus, Chemical physics, Educational aids
1.
M. J.
Moloney
 and
A. P.
McGarvey
, “
A simplified adiabatic compression apparatus
,”
Phys. Teach.
45
,
452
–
453
(Oct.
2007
).
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2.
Some students had insufficient strength to compress a 2-L bottle. We now use primarily 20-oz bottles.
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© 2011 American Association of Physics Teachers.
2011
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