Dry ice is the solid form of carbon dioxide, a gas that makes up a small part of the air we breathe. Unlike regular ice made from water, dry ice is incredibly cold (about negative 109 degrees Fahrenheit) and creates an eerie fog when exposed to air.

The “dry” part of the name comes from an unusual property: dry ice doesn't melt into a liquid like regular ice does. Instead, it sublimes, meaning it transforms directly from solid to gas. When you see that spooky fog rolling off dry ice at a Halloween party or stage show, you're watching it sublimate. The fog itself isn't the carbon dioxide. It's actually tiny water droplets forming in the cold air around the dry ice, like the fog you see when you breathe out on a winter day.

Because dry ice is so cold, it can cause frostbite very quickly if you touch it with bare hands. People use dry ice to keep things extremely cold during shipping, like ice cream or medical supplies. Scientists use it in experiments, and theatrical productions use it to create dramatic fog effects on stage. Despite being made from a gas we exhale with every breath, in its solid form carbon dioxide becomes something quite remarkable.