system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does water stop evaporating when it reaches cloud-level, instead of floating into space?

Actual question from my actually 5 year old son, which I tried to research but couldn't understand the answer myself. Hoping someone can explain to both of us.
gpt
Cloud level itself is dependent on things like the temperature and moisture content of the air mass, and it varies widely. 

Moist air rises until it reaches its dew point, the temperature where that moisture condenses out as visible water vapor that we know as clouds. Whatever altitude that occurs at (based on the atmospheric conditions) is "cloud level". There can be many such layers of clouds at any given time. 

Vertical development, where the clouds are lofted much higher than they would otherwise be, is seen in atmospheric disturbances like thunderstorms that pump warm, humid air up into the atmosphere.