we have all learnt from elementary geography that rain forms after the condensation of moist air that rises from the earth's surface. There are other ways by which it may form, such as by the rise of air over high obstacles, such as a mountain. Anyway, the cloud forms and when it is heavy enough, it falls as rain, in droplets.
Now, what is puzzling is the fact that the rain falls in droplets. My question is, if the cloud is heavy enough to fall as rain, why does it not fall at once as a single mass? I dont understand why the same cloud should fall as small rain drops for a whole thirty or so minutes. What continues to support its weight up there?
Anonymous2007-10-04T07:44:46Z
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Clouds are formed by air which rises and condenses, like you said. This rising air is what in fact keeps the clouds in the air and part of the reason it does not fall all at once.
In order for droplets (or, in most cases in the midlatitudes, ice crystals which melt) to fall as rain, they need to grow to a size large enough so that their downward force (mass*gravity) is enough to overcome both air resistance and the upward motion of the cloud itself. Eventually, evaporative cooling will cause the air to become more dense and the cloud will have a downdraft instead of an updraft, and it's life cycle as a shower is nearing an end.
Drops are not created equal in size. They crash into each other, breaking large droplets into small droplets which can no longer overcome the upward motion and air resistance. Small droplets overtake even smaller droplets as they fall. Fall speed will depend on the size of the droplet, and all the droplets will be falling at different speeds, some won't be falling at all.
This is a pretty simplified version of it all. Here is a USAToday article that you might find interesting. Do a search for the word "hold" and you should find something that is kinda related: http://www.usatoday.com/weather/resources/askjack/archives-clouds-precip.htm
The water vapour rises from earth's surface due to convection to form clouds. The Clouds are basicaly tiny water( or ice or both) droplets very tiny - so tiny that they float on air. For rain to happen these very tiny particles of water or ice need to precipitate - or gather together to form larger droplets. Larger droplets would mean more weight - hence gravity pulls it down in the form of rain.This typically happens when the temperature in the cloud goes down due to various reasons ( like mixing with very cold winds) or by some artificial means the precipitation can be brought about. Thus we have rain. As long as the droplets are tiny - there is no rain only clouds.
Rain, immediately from a cloud is drinkable. that's as sparkling as freshly fallen snow. truly there are exceptions as different have stated, like if the rain grow to be falling down by using a mud hurricane or in a close-by of poisonous smoke from some business area etc. yet, the only debris frequently recent in rain are the condensation nuclei around which they formed. those condensation nuclei are tiny bits of dirt debris or smoke debris or, maximum ordinarily, salt crystals. yet they'd in basic terms account for some factors in line with billion interior the water droplets. So, specific, assuming you commence with a sparkling cup, the rainwater is secure to drink.