Sublimation is a phase change in which a substance transitions directly from a solid to a gas without passing through the liquid phase. This process occurs when the vapor pressure of the solid exceeds the atmospheric pressure at a given temperature, allowing molecules to escape directly into the gas phase.

Common examples include:

• Dry ice (solid CO₂) sublimating at –78.5°C under normal pressure, producing a dramatic fog effect.
• Iodine crystals sublimating to form a purple vapor when heated.
• Snow or frost disappearing without melting on cold, dry days.

Sublimation is used in various applications, such as freeze-drying food, purifying chemicals, and in printing technologies (like dye-sublimation printing). It’s a key concept in physics, chemistry, and material science, especially when studying phase transitions and energy changes.