I'm sure at least some of you do the speed of sound lab with a tuning
fork, half golf tube, and 1 L graduated cylinder. I want to try a
variation by using Alka Seltzer to get the speed of sound in carbon
dioxide. I put the tablet in the tube so that the CO2 would push out the
air in the column. It did not work as I got the same result as for air. I
even tried lifting the tube a bit, adding the tablet, and then lowering
the tube to get the resonant frequency. Same result.
I'm thinking I have to add more tablets or wait a longer time so all the
air is pushed out. Or maybe the best way would be to somehow put a
screen/mesh on the submerged end of the tube in order to capture the
tablet. Then the column would always have CO2 in it since it's heavier
than air.