[Simmer]

Good luck with that []

PS Watch out for water ice forming on surfaces in contact with air, the pure dry ice will be on the surfaces protected by the blanket of CO2

[simeonie]

How do i get my hands on some dry ice. Not literally though because it can hurt

----------------------
http://www.simeonie.co.uk
Check it out. Click on the forums

[David Sparkman]

Many years ago I could buy it from normal ice companies. I would start there and ask them the question.

David

[Steve Vai]

today in chemistry, we were reacting calcium carbonate with hydrochloric acid. As this reaction produces lots of Carbon dioxide, we decided to hold our finger over the bung and let the pressure build up. when we eventually took off the bung, i felt the glass at the top get colder, and we noticed a small amount of the visible CO2 that comes wiht dry ice.

would it be possible to create dry ice in this way, but by trapping the expanding CO2 in a container, possibly a very cold container to help it solidify?

"Turkeys killed my family" - Chip, 02/09/2005, 12:49

[DrN]

which is colder - dry ice or liquid nitrogen? I'm guessing liquid nitrogen, as when you put dry ice in it, it doesn't melt. or maybe it does, and i just can't see it through the smoke.

thats pretty cool about the cup turning blue when you put cold stuff in it. is that how they manufacture those cups that do the same thing? havn't seen them advertised in a while, so I hope they were safe!

when i use acetone as a fixative in plastic dishes, the plastic goes white and rough, almost like its been sandpapered, so it must do something nasty to it!

[rosy]

Liquid nitrogen boils at about 80K (-190C ish). Dry ice, solid CO2, sublimes direct to the gas at about -77C (195K ish). So yeah, you're right, liquid N2 is colder than solid CO2.

[anthony]

The answer you're looking for is crazing. Your cup was probably high density polystyrene, though it doesn't need to be for the effect. The acetone creates areas of low density (crazes) within the plastic, these have a lower refractive index than the surrounding plastic and so scatter light. And why is the sky blue? Small particles scatter light selectively, blue in preference. This effect of the cold is curious, these areas in the plastic must be amorphous, and so expand in the cold, plastics do this. The chances of you achieving this effect if you wanted to are slim, so well done!

[Equalizzer]

where could i get hold of dry ice

I Know A Good Experiment:
mix, H2O and H2O and you get, well, just H2O. =p

[Ylide]

It's sold in the supermarket here, not sure about across the pond.  



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