Do you know if dry ice melts?

Sublimation is the process of a substance passing directly from the solid to the gas phase without becoming liquid. Sublimation is also frequently utilised in theatrical productions to generate fog. Water sublimates under the right conditions, and it exists as a solid at atmospheric pressure below 0° C (32° F). Some ice passes directly to the atmosphere as a gas, despite the fact that it cannot melt at lower temperatures. When the frost on the outside of a window disappears on a very cold day, this process can be easily observed.

Dry ice is made up of solid carbon dioxide that is solid at -109° F (-78.5° C) at atmospheric pressure. If you need to export frozen water-based items, a block of dry ice will suffice, as it does not melt and moves straight from solid to gas. When dry ice is placed in warm water, it quickly sublimates and the gas escapes, forming small droplets of water that form a fog. Because the gas is cold and carbon dioxide is heavier than air, the fog flows across the stage rather than rising above it, making it a popular choice for stage performances.

Dry ice is also used to clean surfaces, similar to sandblasting, by spraying solid pellets to remove impurities and paint. The pellets sublimate into a gas, which means there are no sand mounds to clean up.

Temperature and pressure do, however, affect the state of a substance, whether it is a gas, liquid, or solid. Under normal atmospheric pressure, carbon dioxide does not melt like most other substances, but it can turn into a liquid under higher pressure. Carbon dioxide becomes a liquid at room temperature when the pressure is increased to about five times that of normal atmospheric pressure. Carbon dioxide is also used in fire extinguishers, storing liquid carbon dioxide under pressure, “snow” sprays, and several dry-cleaning techniques for clothes.

In the end, dry ice can turn into a liquid and melt like ordinary ice, but not at normal air pressure. It does not melt because carbon dioxide sublimates, turning from solid to gas, until the air pressure is five times higher. Because of this property, a parcel containing a block of dry ice will arrive safe and undamaged; the block of dry ice will be smaller but not melted.