Dry Ice is frozen or solid carbon dioxide, a colorless and odorless gas that is a normal part of our earth's atmosphere. It is the gas that we exhale during breathing and the gas that plants use in photosynthesis. It is also the same gas added to water to make soda water and carbonated beverages.
Dry ice keeps items colder for much longer than regular frozen water or “wet ice” because dry ice is extremely cold Dry Ice has a temperature of -109.3 degrees Fahrenheit (or -78.5 degrees Celsius). Dry Ice changes directly from a solid back to a gas, which is called “sublimating”, in normal atmospheric conditions without going through a wet liquid stage.
Dry Ice is used for cooling or freezing and keeping things frozen because of this very cold temperature. It is also fairly simple to make and easy to handle using insulated gloves. (See “Safe Handling of Dry Ice”).