Dry ice isn’t frozen water, but rather compressed carbon dioxide. Compared to ice, which freezes at 32 degrees F/0 degrees C, dry ice solidifies at -109 degrees F/-79 degrees C. This makes it useful for keeping things colder longer, like a cooler of fish returning from a fishing trip or your freezer during a power outage. Dry ice is also used in construction projects and by scientists, medical professionals and chemotherapy patients.
It is also a fun addition to a Halloween party or any event that would benefit from fog as a special effect, without the risk of respiratory or throat irritation that can occur with fog machines. Because dry ice is compressed carbon dioxide instead of frozen water, it turns to gas when it melts. This is what creates the cool fog that rolls off it.
We sell dry ice by the pound in sliced blocks and can advise you regarding how much you will need.