Why does dry ice smoke when it meets water?

The reason why dry ice smokes in water is because the temperature of dry ice itself is very low. When put into water or air, it will quickly absorb heat and sublimate, and the water vapor in the nearby air will condense into countless small water droplets. This is white fog. It looks like smoke. This is the same as the "white fog" of popsicles in summer. It's all water droplets, not other gaseous substances.

Dry ice is solid carbon dioxide, which condenses into colorless liquid at room temperature and pressure of 6079.8 kPa. If the temperature continues to decrease and the low pressure increases, the liquid will quickly evaporate and condense into pieces of compacted ice-like solid matter, which is dry ice.

When dry ice is heated and turned into gas, it condenses the water vapor in the nearby air into countless small water droplets, which is white fog. If you pour hot water on dry ice, these white fogs will appear thicker, just like a fairyland.

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Application of dry ice in food preservation

Putting some dry ice in food warehouses or train freezers can not only reduce the temperature, but also make bacteria unable to reproduce, thus keeping fish, meat and fruits fresh. Dry ice has incomparable advantages over ice.

For example, it is very light, accounting for about118 of the same volume of water ice. Light weight is good for transportation. In addition, dry ice will not leave liquid after sublimation, which is cleaner than water ice storage and will not make food wet.

At the same time, the density of carbon dioxide produced by sublimation of dry ice is higher than that of air, so that carbon dioxide gas adheres to the surface of heavy food, and the food is isolated from oxygen, so as to inhibit the growth of bacteria, slow down their metabolism, and ensure the freshness and non-deterioration of fruits, vegetables and seafood products.

It is worth mentioning that making food with dry ice can also create a warm and romantic atmosphere, which can make diners feel like they are in a fairyland. Nowadays, making food with dry ice has become a must for many high-end hotels.