The Mystery of Dry Ice Smoke: Is it CO2?

In summary, the smoke you see from dry ice is actually condensed water vapor caused by the sublimation of solid CO2 into gas. The low temperature of the CO2 causes the surrounding air to reach 100% humidity, resulting in the formation of small water droplets or snowflakes. This phenomenon is similar to the condensation on a cold beverage.
  • #1
GrizzlyBat
36
0
Does anyone know why you can see the smoke coming from dry ice? Is it actually CO2? It does not make sense to me, why could I see CO2 evaporating, but I cannot see it normally? Is it the moisture in the air that I can see reacting with the cold CO2?
 
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  • #2
What you are seeing is the sublimation point where the solid CO2 is converting directly to gas. The smoke as you describe really is nothing more then a dense area of CO2 gas (due to is still low temperature) which quickly expands and dissipates which makes it appear to disappear.
 
  • #3
Backscattered said:
The smoke as you describe really is nothing more then a dense area of CO2 gas (due to is still low temperature) which quickly expands and dissipates which makes it appear to disappear.

I've never heard of gaseous CO2 being visible anywhere atmospheric pressure, so I severely doubt this. It's far more likely that when you're seeing is water droplets condensed out of the surrounding air due to the low temperature.
 
  • #4
Good point, and certainly reasonable, though I have seen the same phenomenon in a dry nitrogen / Co2 atmosphere set at normal atmosphere pressure... maybe there was still some h20 in the system? Anyway good luck with your discoveries.
 
  • #5
It could be that the temperature drop of the air is causing the relative humidity of the air to reach 100%.
 
  • #6
I agree that what you see is condensed atmospheric water. CO2 is invisible. When you use dry ice to make 'smoke', such as for a party, you put it into a tub of water.
 
  • #7
The smoke is condensing water vapor - small snowflakes or droplets of water. Capture it on an object and it gets wet.
 
  • #8
Vanadium 50 said:
The smoke is condensing water vapor - small snowflakes or droplets of water. Capture it on an object and it gets wet.

A bit like the condensation on the outside of my glass of cold beer.Cheers.
 

Related to The Mystery of Dry Ice Smoke: Is it CO2?

1. What is dry ice and how is it made?

Dry ice is the solid form of carbon dioxide (CO2) that is created by compressing and cooling gaseous CO2. It is then formed into solid blocks or pellets, which can be used for various purposes.

2. Why does dry ice create smoke?

Dry ice does not actually create smoke, but rather it sublimates (transforms directly from a solid to a gas) at a temperature of -109.3°F. This rapid phase change results in the visible "smoke" or fog that is seen when dry ice is exposed to air.

3. Is dry ice smoke harmful to breathe?

Dry ice smoke is composed of carbon dioxide gas, which is not toxic in small amounts. However, if exposed to high concentrations of CO2, it can cause dizziness, headaches, and difficulty breathing. It is important to use dry ice in well-ventilated areas and avoid prolonged exposure to the smoke.

4. Can I touch dry ice with my bare hands?

No, it is not safe to touch dry ice with bare hands. Dry ice is extremely cold (-109.3°F) and can cause frostbite or burns. Always handle dry ice with protective gloves or tongs.

5. Can dry ice be used for cooling food and drinks?

Yes, dry ice is commonly used for keeping food and drinks cold without the mess of melting ice. However, it is important to handle dry ice properly and avoid direct contact with food or drinks as it can cause freezer burn or carbonation.

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