re: Cloud Chamber

["Brian Rees" <brees@lanl.gov>]

Mike,

First of all, paint the inside of the can black.  Cut a small (1/2-1") hole 
in the side of the can, about an inch above the bottom (top's removed).   
And you'll need some ethyl alcohol (the stuff you can drink) and a 
flashlight. The can sits on top of the dry ice, with the open end up.  The 
plastic wrap covers the top of the can, and tape some over the hole in the 
side of the can.  Pour some (about a CC or so) of the alcohol into the can, 
put the lantern mantle inside the can, and cover the top.  Shine the 
flashlight through the hole.

What should happen is that the alcohol vapor will stay near the bottom of 
the can, the alphas from the mantle will leave a track in the vapor, and 
the sidelight will show the track.  I've had problems with the amount of 
alcohol vapor (not using enough), and not waiting long enough for the vapor 
to form a layer.  

Good luck,

Brian Rees
brees@lanl.gov