Question

We want to measure the speed of sound without having water vapor as a possible source of error. Which of the following scenarios would work?
Place dessicant in the tube.
Use mercury instead of water, since mercury has a very low vapor pressure.
Instead of water, insert the tube into fine sand or powder.
Perform the experiment in a vacuum.
Use a fixed length tube with dry air or nitrogen, and a tunable speaker instead of the tuning fork

Helga wants to measure the speed of sound in a similar experiment. However, she wants to show off and use an open-ended pipe instead of a pipe closed at one end. Which of the following approaches might be appropriate?
Use two pipes that fit closely together, so the overall length of the pipe can be changed.
Use a fixed length pipe, and use a sound generator that can produce various frequencies.
Use a fixed length pipe, and move the tuning fork around until it resonates.
Produce several tubes of varying lengths, and find the tube that resonates.
Insert the tuning fork into the open tube, forcing the tube to resonate.

In your experiment, how does the amplitude of the tuning fork vibration affect the results? t/f
Makes the speed of sound come out low.
Sounds louder or softer, but does not change the calculations.
Has no effect.
Makes the wavelength too low, resulting in a calculated speed too high.
Makes the resonant position too low, resulting in a calculated speed too high.

Answer 1

-> Put the tube into sand or powder - that does not removes the water vapour inside the tube . So no, this won't work.
-> In vacuum - can't work because without a medium,so,there's no sound.
-> Use a fixed length tube with dry air or nitrogen - this would work nicely.

2) tuning fork vibration makes the resonant position too low, resulting in a calculated speed too high.