Dry ice is a genericized trademark for frozen carbon dioxide. The term was coined in 1925.
It is used for:
- producing "dry ice fog" for special effects: when dry ice is put into contact with water, the frozen carbon dioxide sublimates into a mixture of cold carbon dioxide gas and cold humid air. This causes condensation and a fog.
- cleaning: shooting tiny dry ice pellets at a surface cools the dirt and causes it to pop off. This is analogous to sandblasting with the advantage that the abrasive agent in this case, dry ice, sublimates to nothing.