In this vid, “mathemusician” Vi Hart and Sal Khan (of the amazing Khanacademy) discuss the difference between linear and logarithmic scales and human perception. I like their joking idea of a liner scaled piano where the keys would get fatter and fatter as you moved up the scale.

For those who are sticklers enough to be annoyed by the fact that Vi just makes up frequency numbers for “C” (’cause she can’t remember the freq off the top of her head), on the blog Drew’s Day, Andrew Morrison provides some details Vi and Sal did not concern themselves with (the point of their video being more about conveying the idea of linear vs. logarithmic conceptually) and expands on several ideas.