By Rashmi Wickramasinghe
Fog is like thick clouds near the earth’s surface. The humidity of the atmosphere should be very very high to generate fog. Then is it just condensed water vapor along with dust or some air pollutants. Water vapor has to be condensed around these solid microparticles to form fog.
Dry ice is used to generate fog artificially.
What is dry ice?
Dry ice is the solid form of carbon dioxide gas. The gas has to be cooled, at least to -78.5C under high pressure to transform into its solid which is dry ice.
If dry ice gets into contact with your hand, the water in the cells freezes then the cells rupture causing damages similar to burns that are called ice burns.
⚠️ So whenever you touch dry ice remember to wear a protective cloth!
How to make fog with dry ice?
Have you ever noticed fumes around dry ice exposed to the air? When dry ice gets exposed to the air it directly turns into gas without turning into liquid. The temperature of gaseous Carbon dioxide is lower than the temperature of the surrounding environment. So, the water vapor in the air condenses making small water droplets that can be seen as a fume.
This fume is not enough to create a massive fog. That’s when hot water comes to aid. When a chunk of dry ice is put into hot water, it vaporizes and forms carbon dioxide bubbles inside water. These bubbles escape to the air causing the water vapor in the air which has a higher temperature to condense and form a thick fog.
😮 Why the fog does not go up into the sky? The fog is colder than the atmospheric temperature. Also, the density of carbon dioxide is high. So, fog tends to drop towards the floor