Effect of Liquid Level on Standing Wave Frequency in a Soda Bottle

[MAins]

A partially empty soda bottle will produce standing waves in the air above the liquid if you blow across the neck of the bottle. There will be a displacement antinode at the neck and a node at the surface of the soda. What happens if you drink more soda and repeat the experiment?

a) no change in the sound produced
b) frequency of the sound will increase
c) frequency of the sound will decrease
d) wavelenth of the sound will increase
e) wavelength of the sound will decrease
f) pitch of the sound will increase
g) pitch of the sound will decrease

Which one and why??
I figure the mass in the bottle will decrease so that might affect it, maybe the wavelength will increase & frequency decrease, not sure about the pitch... actually not sure of any of this. Please help!

 

[Dr. Jekyll]

...standing waves in the air above the liquid...

What happens with the air (wavelength) when you drink more soda? Mass of the soda doesn't have anything to do with it.

 

[astrorob]

You're on the right lines..

If I were to tell you that the higher the frequency of the wave then the higher resulting pitch, would that help?