Here's how it works:

1. Evaporation: Water on the Earth's surface (oceans, lakes, rivers) evaporates into the atmosphere as water vapor.

2. Rising Air: This water vapor rises with warm, moist air currents.

3. Cooling: As the air rises, it cools, and the water vapor within it begins to condense into tiny water droplets or ice crystals.

4. Condensation Nuclei: These water droplets or ice crystals need tiny particles in the air, called condensation nuclei, to form around. These nuclei can be dust, salt, or other small particles.

5. Cloud Formation: As more water vapor condenses, the droplets or crystals become larger and more numerous, forming visible clouds.

The type of cloud that forms depends on the temperature and other atmospheric conditions.