Dry ice is the solid form of carbon dioxide. At normal atmospheric pressure, the freezing point of carbon dioxide is -78.5 degrees Celsius, which is very useful in keeping objects frozen or low temperature.
At present, dry ice has been widely used in many aspects. Dry ice is directly sublimated from solid to gas when heated, and directly converted into gas without changing into liquid, so its phase change will not produce liquid, so it is called "dry ice".
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Application of dry ice:
1. Making artificial rainfall: When dry ice is sprinkled on the cloud by plane, the small water droplets in the cloud will be frozen into many small ice crystals, so that more water vapor will condense on it, become raindrops and land on the ground.
2. Clouding: Because the temperature of dry ice is very low, it will absorb the surrounding heat when sublimating, and it can condense the water vapor in the air into small water droplets, so there is white fog. In stage performances, dry ice is often used to create special effects like clouds.
3. Refrigerant: Because the density of carbon dioxide is higher than that of air, it will stay below the air, so dry ice can still be coated on frozen items after sublimation, which can maintain a good freezing effect. Especially in air transportation, it is often used for items that need special freezing.
Reference source: Baidu Encyclopedia-Dry Ice