Pianos can't be perfectly tuned - it's a mathematical fact!
Thanks to http://www.audible.com/minutephysics for supporting MinutePhysics.

Equal tempered tuning: https://en.wikipedia.org/wiki/Equal_temperament

Just Tuning: https://en.wikipedia.org/wiki/Just_intonation

Harmonics: https://en.wikipedia.org/wiki/Harmonic

Pythagorean vs Just Tuning: https://www.youtube.com/watch?v=QaYOwIIvgHg

Thanks to Patreon supporters for making MinutePhysics possible!

MinutePhysics is on Google+ - http://bit.ly/qzEwc6
And facebook - http://facebook.com/minutephysics
And twitter - @minutephysics

Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!

Music by Nathaniel Schroeder http://www.soundcloud.com/drschroeder Created by Henry Reich