Current Events > You know what I never understood about clouds?

(+) Yeah! (+)

Water vapor goes up (understand),
Starts sticking together (don't understand),
Gets more dense as it sticks together more (definitely don't understand),
And after weeks of doing this, suddenly surpasses the density of air, every drop at the same time (WTF),
And for some reason plummets to Earth instead of drifting down slowly, like it should shortly after surpassing air density (I give up)
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I just recently learned this year that water goes up as vapor, but that clouds aren't vapor. It's already condensed water droplets suspended in air, until they are too heavy to fly, and just fall as rain.
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Fuckin' molecules, how do they work?!

It's already condensed water droplets suspended in air,

Right, which... how?

Even if they're tiny droplets, liquid water is still much more dense than air. I suppose they do have more surface area but I mean is there a perpetual updraft up there pushhing them up?
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Here:
https://en.wikipedia.org/wiki/Cloud#Physical_forms
How the air becomes saturated[edit]
Main article: Cloud physics

Progressive evolution of a Single Cell Thunderstorm
File:Cloud evolution in under a minute.ogv
Time-lapsed cloud evolution from cumulus humilis to cumulonimbus capillatus incus in under a minute.
Air can become saturated as a result of being cooled to its dew point or by having moisture added from an adjacent source. Adiabatic cooling occurs when one or more of three possible lifting agents – cyclonic/frontal, convective, or orographic – causes air containing invisible water vapor to rise and cool to its dew point, the temperature at which the air becomes saturated. The main mechanism behind this process is adiabatic cooling.[71] If the air is cooled to its dew point and becomes saturated, it normally sheds vapor it can no longer retain, which condenses into cloud. Water vapor in saturated air is normally attracted to condensation nuclei such as dust and salt particles that are small enough to be held aloft by normal circulation of the air.[16][72]

Frontal and cyclonic lift occur when stable air is forced aloft at weather fronts and around centers of low pressure.[73] Warm fronts associated with extratropical cyclones tend to generate mostly cirriform and stratiform clouds over a wide area unless the approaching warm airmass is unstable, in which case cumulus congestus or cumulonimbus clouds will usually be embedded in the main precipitating cloud layer.[74] Cold fronts are usually faster moving and generate a narrower line of clouds which are mostly stratocumuliform, cumuliform, or cumulonimbiform depending on the stability of the warm air mass just ahead of the front.[45]

Another agent is the convective upward motion of air caused by daytime solar heating at surface level.[16] Airmass instability allows for the formation of cumuliform clouds that can produce showers if the air is sufficiently moist.[75] On comparatively rare occasions, convective lift can be powerful enough to penetrate the tropopause and push the cloud top into the stratosphere.[76]

A third source of lift is wind circulation forcing air over a physical barrier such as a mountain (orographic lift).[16] If the air is generally stable, nothing more than lenticular cap clouds will form. However, if the air becomes sufficiently moist and unstable, orographic showers or thunderstorms may appear.[77]


Windy evening twilight enhanced by the Sun's angle, can visually mimic a tornado resulting from orographic lift
Along with adiabatic cooling that requires a lifting agent, there are three major non-adiabatic mechanisms for lowering the temperature of the air to its dew point. Conductive, radiational, and evaporative cooling require no lifting mechanism and can cause condensation at surface level resulting in the formation of fog.[78][79][80]

There are several main sources of water vapor that can be added to the air as a way of achieving saturation without any cooling process: Water or moist ground,[81][82][83] precipitation or virga,[84] and transpiration from plants[85]
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