Discover how the solid-to-gas phase change happens around you every day, from dry ice to freeze-dried coffee.
Click any card to learn more about the science behind it.
Frozen carbon dioxide turning directly into spooky fog.
Snow disappearing without melting in cold, dry weather.
Using vacuum sublimation to preserve food and coffee.
Solid naphthalene slowly turning into insect-repelling gas.
Printing high-quality photos using heated solid dyes.
Ice sublimating directly out of frozen food.
The Science: Dry ice is solid carbon dioxide (CO₂). Because the triple point of CO₂ is 5.18 atm (over 5 times normal atmospheric pressure), liquid CO₂ cannot exist at room conditions. When exposed to room temperature air, the solid CO₂ absorbs heat and transitions directly into CO₂ gas at -78.5°C (-109.3°F).
Why the fog? The "fog" you see isn't actually CO₂ gas (which is invisible). It's water vapor in the surrounding air condensing into tiny liquid droplets because the sublimating CO₂ gas is so intensely cold!
The Science: Have you ever noticed snow piles shrinking on days when the temperature never goes above freezing? In cold, dry, and windy conditions, the air pressure of water vapor is very low. Sun hitting the snow provides enough energy for the ice crystals to sublimate directly into water vapor, bypassing the liquid phase entirely.
This process is responsible for significant mass loss in mountain glaciers and snowpacks around the world.
The Science: Freeze-drying is the commercial application of sublimation. Food (like coffee or astronaut ice cream) is frozen, then placed in a strong vacuum chamber. The vacuum lowers the ambient pressure below water's triple point (0.006 atm). When gentle heat is applied, the solid ice inside the food sublimates directly into vapor.
This leaves the physical structure of the food completely intact, preserving texture and nutrients much better than traditional heat-drying.
The Science: Mothballs are made of toxic chemical solids that have a high vapor pressure at room temperature. They slowly sublimate over months, turning from a solid ball directly into a strong-smelling gas that permeates closets and repels fabric-eating moths.
The Science: Used for high-end photo printing and custom apparel. The printer uses heat to turn solid colored dyes on a ribbon directly into a gas without passing through a liquid phase. The gaseous dye penetrates the paper or fabric, then quickly cools and returns to a solid.
This creates a continuous, high-quality color tone rather than the distinct dots produced by standard inkjet printers.
The Science: If you leave meat or vegetables in the freezer without airtight packaging, they develop "freezer burn"—dry, tough, discolored patches. Even in a freezer, the ice crystals inside the food slowly sublimate into water vapor.
The vapor travels to the coldest part of the freezer (the walls) and undergoes deposition (gas to solid) forming frost. The result is dehydrated food.