Cool!

[captpackrat]

I dug up my trusty non-contact thermometer (because none of the other thermometers I have could measure below -20C), then turned one of those "compressed gas dusters" upside down and sprayed the liquid into a spot on the desk.

I managed to get it down to -35F (-37.2C)!

Interestingly, if you spray enough of the liquid into one spot, it forms a white frost, which is NOT ice. If you drop the frost into water, it boils, so I assume it's dry ice, or something like it.

Comments

[wolffit.livejournal.com]

That compressed gas duster is pure r134a, the same refrigerant that's used in automotive refrigeration systems. Lotta people are surprised by this, normally associating r134a with bad nasty flammable ozone depleting baby killing substances. They call it by it's chemical name on the back of the can which avoids this issue.

The resulting white frost could be any # of things, ranging from frozen carbon dioxide distilled from the air to frozen moisture and anything else present.

Careful, it'll give you frostbite real quick. It's non-flammable though and unlike freon, isn't too much of a suffocation hazard. You don't wanna displace the oxygen you're breathing with anything though, even water will kill ya.

- Keman