Re: [Phys-L] Guitar String Excitation Visualized.

[Zeke Kossover <zkossover@exploratorium.edu>]

The weird display isn't the actual waveform of the string. It is a property
of the shutter on the iPhone. Instead of blanking (rather clearing) the
entire CMOS on each frame, it clears a line at a time and then clears the
next line. The effect is to scan in time so that the entire frame isn't
from the same moment in time.

The effect is called "rolling shutter" and you can learn more about it
here.
http://www.diyphotography.net/everything-you-wanted-to-know-about-rolling-shutter/

You'll find lots of weird videos likes propellers that look like they are
coming apart. https://www.youtube.com/watch?v=LVwmtwZLG88

At the Exploratorium we have a mechanical exhibit that show this same
property, the Oscylinderscope. You can check out a video of it here.
https://www.youtube.com/watch?v=Ys9D48xFJRA

On Wed, Jan 21, 2015 at 12:17 PM, brian whatcott <betwys1@sbcglobal.net>
wrote:

> Drop the phone in the guitar and play:
>
> http://www.wimp.com/insideguitar/
>
> Brian Whatcott    Altus
> _______________________________________________
> Forum for Physics Educators
> Phys-l@www.phys-l.org
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