What is sublimation?

Sublimation is when a substance changes directly from a solid into a gas without becoming a liquid first. A common example is dry ice, which turns into carbon dioxide gas at ordinary atmospheric pressure.

Quick Scoop

  • State change: solid →\rightarrow → gas.
  • No liquid stage: the material skips melting completely.
  • Energy needed: it absorbs heat, so it is an endothermic process.
  • Examples: dry ice, iodine, naphthalene mothballs.

Why it happens

Sublimation happens when molecules at the surface of a solid gain enough energy to escape directly into the air. This is more likely under certain temperature and pressure conditions, especially below the substance’s triple point.

Real-world uses

  • Freeze-drying: water is removed from frozen food by sublimation under vacuum.
  • Purification in chemistry: some solids can be heated so they vaporize and then re-condense as a purer solid.
  • Printing and crafts: “sublimation printing” uses heat to turn ink into gas so it bonds with a material surface.

Bottom line

If you want the simplest definition: sublimation is a solid turning straight into a gas. If you'd like, I can also explain the difference between sublimation, evaporation, and deposition.