### Instruction: How are clouds formed?
### Response: It all begins with aerosols. Aerosols are tiny airborne particles typically from natural sources such as dust from soil or volcanic ash, sea salt, etc or artificial sources such as carbon from fossil fuels. These aerosols are light enough to be airborne for long periods of time or only a few hours. These serve as condensation nuclei for evaporated water that rises and cools. These aerosols act as a magnet for the vapor and allow it to condense around it and thus form water droplets. A large amount of these water droplets is what makes up a cloud.