[Aaron Zimmerman]

Aaron Zimmerman  asked the Naked Scientists:
Hi my name is Aaron, I am a student attending the University of Wisconsin in the U.S.  

My question is about dry ice, most people are familiar with it's smoky effects.  As I understand it, dry ice is a good example of a sublimation, of a solid going directly to a gas.  My question is if the solid white carbon dioxide is changing directly into a gas then why can I see the smoke, since carbon dioxide is colorless?  Is is water condensing out of the air, or small bits of particle picked up in the currents formed by sublimation?  

Thanks for any help, love your show, just caught up on 3 years of backlogs in the last three months!  

Keep it coming and keep it naked!
   
Aaron Zimmerman
What do you think?

[Madidus_Scientia]

Yes, it is just the fog from water condensing from the air in the colder carbon-dioxide gas

[NeilT]

Whatever you do, don't sit on it!

http://news.bbc.co.uk/nolpda/ukfs_news/hi/newsid_3579000/3579331.stm

[Make it Lady]

I see the future. I see a tall, dark, handsome stranger. Sorry, think you got your answer and couldn't resist.

[chris]

The lady in the picture seems to have quite an icy look on her face, if I may say so.

Chris