Carbon dioxide in Cold Temperatures

[noz92]

The tempereture outside where I'm at is [math]6.7 \ensuremath{^\circ}C[/math] ([math]44 \ensuremath{^\circ} F[/math], [math]279.8 \ensuremath{^\circ} K[/math]). So when I blow outside, the [math]CO_2[/math] from my lungs becomes visible. Why does this hapen?

[JaKiri]

The tempereture outside where I'm at is [math]6.7 \ensuremath{^\circ}C[/math] ([math]44 \ensuremath{^\circ} F[/math], [math]279.8 \ensuremath{^\circ} K[/math]). So when I blow outside, the [math]CO_2[/math'] from my lungs becomes visible. Why does this hapen?

 

That's not Carbon Dioxide, that's the water vapour precipitating from your breath.

[Ophiolite]

That is not carbon dioxide. It is condensed water droplets. The relatively cool air cannot hold as much water vapour as the warm air in your lungs.

[noz92]

Okay, then forget the question I asked above .

[Martin]

OK here is another question about "CO2 in cold temperatures"

 

suppose you have a block of dry ice (co2) in an icechest

How cold does the it get?

 

there is a vent to let the co2 and/or air escape so that pressure doesnt build up------so the pressure in the icechest stays at normal atmospheric.

after a while the block of solid co2 is sitting in an atmosphere of mostly co2.

[jdurg]

The temperature will get as cold as solid CO2 is. So you'd have to look up the temperature at which solid CO2 begins to sublimate, and that's how cold the temperature will be at equillibrium.

[Ophiolite]

-78.5 C

[Gilded]

"-78.5 C"

 

Hmmm... What was the low temperature record in nature (on Earth)? -71? Or below the sublimation point?

[Ophiolite]

The lowest temperature ever recorded anywhere on earth, -88.3° C (-126.9° F), was on August 24, 1960, at Vostok Station.

http://ireland.iol.ie/south-aris/climate.htm

[Gilded]

Yum. That sounds CO2-sublimicious.

 

Edit: Btw, do you have different words in the English language for going straight from gas to solid and going straight from solid to gas, or is it just "sublimation" in both cases?

[jdurg]

Going from solid to gas is defined as sublimation, and I believe the reverse process is described as crystalization. (Though people usually add 'from a gas' when describing the process. I.E. Iodine Vapor).

[budullewraagh]

actually, deposition is the opposite of sublimation :\

[jdurg]

actually, deposition is the opposite of sublimation :\

 

 

THAT's the word I was trying to think of. Deposition.

[Nave]

you know what a cool thing to do in the freezing cold(i did it in -20 F) weather is to take a cup of boiling water and just throw it and it freezes in mid air.

[Gilded]

"you know what a cool thing to do in the freezing cold(i did it in -20 F) weather is to take a cup of boiling water and just throw it and it freezes in mid air."

 

Finland didn't really get that kind of temperatures this winter, but if the next winter's different perhaps I'll try that. And wouldn't it be more effective if the water was already somewhat cold?

[YT2095]

nope, boiling water freezes faster than cold does.

 

contra-intuitive I know, but it does

[jdurg]

nope' date=' boiling water freezes faster than cold does.

 

contra-intuitive I know, but it does [/quote']

 

 

Really? Hmmm. I'd like to see some scientific data to back that up.

[Gilded]

Hot water freezes faster only if you throw it in the air, as it's partially steam, and scarce water molecules are easier to freeze than... less scarce water molecules. If you have a bowl of 50 C water and a bowl of 25 C water, with equal masses and so on, the 25 C water freezes faster.

 

http://www.physlink.com/Education/AskExperts/ae7.cfm

[YT2095]

Really? Hmmm. I'd like to see some scientific data to back that up.

Certainly

 

have a look at the link in post #6 in here: http://www.scienceforums.net/forums/showthread.php?t=4931

[jdurg]

Hot water freezes faster only if you throw it in the air' date=' as it's partially steam, and scarce water molecules are easier to freeze than... less scarce water molecules. If you have a bowl of 50 C water and a bowl of 25 C water, with equal masses and so on, the 25 C water freezes faster.

 

http://www.physlink.com/Education/AskExperts/ae7.cfm[/quote']

 

That was my deduction as well. If I have a 1 gallon jug of boiling water and a 1 gallon jug of cold water, I'm pretty sure the cold water will freeze sooner. A noticeable change in temperature, however, will occur with the boiling water much quicker since us humans are able to perceive extreme changes in temperature pretty quickly.

[swansont]

nope' date=' boiling water freezes faster than cold does.

 

contra-intuitive I know, but it does [/quote']

 

You really have to add "under some circumstances" to this, because it's not universally, or even usually, true.

[YT2095]

You really have to add "under some circumstances" to this, because it's not universally, or even usually, true.

I`ll go along with that, "Wording things" isn`t my strongest point at all, thanks for the correction/re-wording

[budullewraagh]

i think he's saying that if you take water vapor at incredibly low pressures and expose it to a really cold setting the gas will freeze

[Nave]

Jdurg if u ever want some data to try and back that up when u have a really cold temp outside just take two different cups. one with boiling water and one with room temp. and throw them. the room temp wont do anything while the boiling one will freeze in the air. I think next time i get into those temps ill try it with the water just sitting there and let u know the results..but if u ever get a chance to do it its quite amazing...

[Gilded]

Nave, we already discussed the part that causes that: As some of the boiling water is in steam form, and more of it is in steam or less-scarce form when it's thrown, of course it freezes (at least partially) faster than the room temp water. But obviously, if you have a 5 C cup of water in the freezer and a similar sized 50 C cup of water in the freezer, the 5 C water freezes faster.