Cumulus clouds form as warm, invisible air &quot;bubbles&quot; (thermals) containing water vapor rise from the earth's surface, cool with ascension, and condense at the condensation level.
(Cumulus clouds; form; ) (thermals; containing; water vapor rise from the earth's surface, cool with ascension, and condense at the condensation level)
Cumulus clouds thermals
form containing
water vapor rise from the earth's surface, cool with ascension, and condense at the condensation level