Fun with a digital microscope: Measuring the Avogadro Number using videos of Brownian Motion.
http://access2010.wikidot.com/am AM Calibration, hair, π, and NA Table
http://access2010.wikidot.com/pm PM Calibration, hair, π, and NA Table
don't forget to upload your Excel spreadsheet file for π
Brownian Motion Measurements:
At 40x magnification: after focusing on a field with 20 or more microsphere in the suspension,
wait for the flow of the fluid to subside, then, without causing any vibrations (take the mouse
off the table and hold it in your hands), take a 2 minute of 1-sec-per frame-lapse movie.
Digitize the motion of 10 particles over the SAME 30s time interval (important!)
Take one sample every 3 seconds and record your data in the following Excel template
(download it, look at it and save it before you start)
Repeat for 100x, in a field with at least 10 particles
digitize 7 particles every 3 seconds over the SAME 30s interval