Dry ice is frozen carbon dioxide (C02), the gas we exhale as we breathe. It is much denser and colder than traditional ice. Dry Ice is -109.3¿ F (-78.5¿ C). Traditional ice is 32¿ F (0 degrees C). In addition, dry ice doesn't melt - it sublimates. Sublimation is the process of going directly from a solid to a gas. Dry ice bypasses the liquid form, giving it its name "dry" ice. The first step in making dry ice is to turn the carbon dioxide gas into a liquid. This is done by compressing the C02 and removing any excess heat. The C02 will liquefy at a pressure of approximately 870 pounds per square inch. Next, the pressure is reduced over the liquid carbon dioxide by sending it through an expansion valve. Part of the liquid sublimates, causing the remainder to freeze into snow flakes. The dry ice snow is then compacted together under a large press to form blocks. Dry ice is much heavier than traditional ice, weighing about the same as standard bricks.