Dry ice is the solid form of carbon dioxide (CO2). Unlike regular ice made from water, which forms at temperatures below 0°C (32°F), dry ice forms at temperatures below -78.5°C (-109.3°F). At atmospheric pressure, carbon dioxide cannot exist as a liquid, so it undergoes a process known as "sublimation," wherein it transitions directly from its solid form to a gas without passing through the liquid state.
To create dry ice, gaseous carbon dioxide is compressed and cooled to very low temperatures, typically below -78.5°C (-109.3°F), until it solidifies into dry ice. The resulting dry ice is a white, solid substance that is much colder than regular ice and emits dense, white clouds of carbon dioxide gas when it comes into contact with warmer temperatures or liquids.
Dry ice is commonly used for various purposes, such as refrigeration, cooling, special effects in stage productions, and transportation of perishable goods. It's essential to handle dry ice with care, as its extremely low temperatures can cause frostbite and its sublimation can lead to the buildup of carbon dioxide gas in confined spaces.