Sublimation is the process where a solid changes directly into a gas without passing through the liquid phase. Here's a real-life example:
Dry Ice
Dry ice is the solid form of carbon dioxide (CO2). At room temperature and atmospheric pressure, dry ice sublimates, meaning it transitions directly from a solid to a gas. This is why dry ice is used in special effects like fog machines and theatrical productions.
Here's how it works:
- Dry ice has a very low sublimation point of -78.5 °C (-109.3 °F).
- When dry ice is exposed to room temperature, it absorbs heat from the surroundings.
- This heat energy causes the CO2 molecules to vibrate rapidly, breaking free from their solid structure and transforming into a gas.
- The gas is denser than air, creating a visible fog effect.
Other real-life examples of sublimation include:
- Freeze-drying food: This process involves freezing food and then lowering the pressure, allowing the ice to sublimate, removing water from the food.
- Snow disappearing in cold weather: While it might seem like snow melts, it can also sublimate directly into water vapor, especially in dry, cold conditions.
- Mothballs: Mothballs are made of naphthalene or paradichlorobenzene, both of which sublimate at room temperature, releasing a vapor that repels moths.
