On Feb 8, 12:56 pm, "RCE" wrote:
"JoeSpareBedroom" wrote in message news:bbKyh.2321
The alcohol gone - water remaining & freezing idea seems the most
plausible at this point.

Water and water vapor is an interesting and complex subject. I spent the
better part of my career dealing with their effects and properties in
reduced pressure (vacuum chambers) vessels. Water vapor does not follow
natural gas laws and is the bane of those of us trying to create high vacuum
environments (equal to 200-300 miles in space) here on earth.

Place a cup of water in a large vacuum system and begin to remove the air,
reducing the atmospheric pressure. The water will quickly freeze at the
reduced pressure. Continue to reduce the pressure and the block of ice will
suddenly start to rapidly boil ... in the blink of an eye. Continue to
reduce the pressure and it will suddenly freeze again and begin to sublimate
(goes from solid to vapor without becoming a solid).

It also has weird properties when it condenses. Picture a snowflake with
all of it's points. Each point becomes a nucleation site for the next bit
of water vapor. Enough of them and they form an insulating lay whereby no
further nucleation takes place. That's why you don't get 3 inches of frost
on your windshield. The process stops once the outer surface is insulated
sufficiently from the cold glass where the initial nucleation took place.

That's the third time in two days I've heard the term nucleation.

That's the effect you get when you drop a Mentos into a bottle
of diet soda.

Funny - I never looked at frost like that.