Science Buddies: "Ask an Expert"

Hello!
My question is "How does the density of liquids affect pitch when playing music on crystal glasses?". As I was writing my ERP (Experimental Research Plan), I was think about constants. I was wondering if it would be a good idea to change "density" to "sound" in my question. Do you think that would eliminate some uncontrolled variables?

No. You are confusing cause and effect.

"How does the density of liquids affect pitch..." That is how a propery of a liquid affects the pitch of the sound.

"How does the density of sound affect pitch..." This reduces to "How a propery of a sound affects the pitch of the sound.

If you are asking how the density of a liquid affects the pitch of the sound made by a glass partially filled with a liquid, then state the question that way. Bear in mind that density may not the only variable you introduce. I am not sure how the density and the speed of sound propogation through the liquid are related. Most mateerials require the elasticity to be consideered too.

If this were my project, I would start with comparing the sound's pitch to the liquid level in the glass, changing the density by adding salt to the water, repeating the first step, and compare the liquid levels to the sound's pitch.