Dry ice is a solid form of carbon dioxide. It's used primarily as a cooling agent, but can be used in fog machines at theatres and private events for dramatic effects.
The advantages of Dry Ice include lower temperatures than that of ice cubes in water without leaving any residue.
It is useful for preserving frozen foods where mechanical cooling is unavailable, and also plays a key role in a variety of industries; Medical, Commercial, Industrial, Food and Beverage industries, among many others more.