Re: things to do with dry ice?

[Stefan Jeglinski <jeglin@4PI.COM>]

> If you can keep the dry ice long enough, you might consider building a
> Wilson Cloud Chamber which as you might already know consists of a pin
> set vertically in an enclosed jar. On the head of the pin is glued a
> small amount of flourescent material as can be obtained from an old
> watch face whose hands glow in the dark. The jar is set on dry ice and
> black cloth is draped around the jar as a backdrop. After a few minutes,
> one can observe the tracks of particles shooting away from the pinhead.


Right, but IIRC this requires alcohol as well. Commonly, black felt
is soaked with alcohol, and underlying dry ice super-cools the
alcohol vapor. The particles act as a perturbation which causes the
alcohol to freeze out locally into crystals, the path of which can be
seen. Is this not the correct generic explanation?



Stefan Jeglinski