Self-proclaimed "recreational mathemusician" Vi Hart has posted an excellent short film explaining the science and mathematics of sound, frequency, and pitch. Basically Hart shows us how the chromatic scale was originally measured, how musical instruments work, and how we hear sound. It's playful and smart -- exactly what you need to watch right now if you have even the vaguest geeky interest in music, math, or sound.

Sample lines (shown as speech bubbles on a map, when describing how some cultures independently created similar systems of tonality):

Africa: "So a note and the note with twice the frequency...totally are like the same note, am I right?"

Germany (ish): "Oh man, octaves! Love 'em."

Madagascar: "Yeah!"

Peru: "OMG me too!"

USA (Motown): "Yo what about 5ths?"

USA (rest of country): "I like 5ths."

UK: "The ones with the 1:3 ratio?"

South Africa: "Yeah, I could go for those."

Hart also notes in her YouTube description a minor narration error. I thought I'd note it here before we got complaints:

Correction: it is the "Basilar" membrane, which is what I say, but somehow between recording the script and actually drawing the stuff I got confused and thought I just pronounced my Vs poorly. Always sad to have such a simple and glaring error in something I put hundreds of hours of work into, but a "Vasilar" membrane can be the kind that a Vi draws to explain Viola Vibrations, I guess! Making up new words is just so prolightfully awstastic.

If you like this, you'll love Hart's blog. She also takes donations to help fund her work, and publishes what I assume is a Google Voice phone number where you can send her text messages or voicemails.

(Via Laughing Squid.)