# What does pitch tell you about an object?

What does pitch tell you about an object? For example, if you know the pitch that a fork resonates at, what does it tell you about the fork? Is it telling you the mass of the object (or anything else)?

This question came to me because a while back I was thinking that objects of the same color tend to be made of the same general substance. (Specifically relating clouds and snow based on their shared color to my niece).

It’s telling you about the length of the resonating object – the tines of the fork. Density of the material also factors into this.

“objects of the same color tend to be made of the same general substance”? Rubbish.

Is there a formula?

There are a whole bunch of different formulas, for objects of varying shapes. The simplest case would be a long, thin rod which is not restrained in its movement in any way: It can have any pitch of the form n*v/(2L), where v is the speed of sound in the material of the rod, L is the length of the rod, and n can be any integer. The velocity of sound, in turn, is given by v = sqrt(C/rho), where rho is the density of the material, and C is something called the modulus of elasticity, a number which describes the springiness of the material.

Here’s a page about tuning forks, which does have a formula for tuning forks made of specified dimensions but with different materials. I’m not an expert (this is just something I found by googling), so I can’t vouch for the information.

Nametag-

To explain in one way: Looking down from an airplane, any blue patches tend to be water, white patches tend to be snow, green patches tend to be plant life, and yellow patches tend to be sand.

As you go down to the basic level I suppose things get more complicated, but I believe the idea still applies in nature to some degree. I’m curious as to how you are viewing the quote?

It reads as though you might expect amethysts and aubergines to have similar compositions.