why do rain fall in droplets and not as wires or long uninterrupted columns of water?
150463
There are a couple of reasons that work together to explain this situation. The first one has to do with how raindrops form. \n\nNow, it may seem silly to make such an obvious statement as, "Rain always falls from clouds." But once it has been said, we can then ask, "What is going on inside those clouds?" And that question leads us to plenty of relevant information! \n\nDo you remember the last time your local weather was described as being "hot and humid"? Do you remember what it FELT like? Do you also remember what the air LOOKED like? The reason I am asking these questions is because it is important to know that ordinary water is commonly found in one of three forms: solid, liquid, or gas. The liquid form is what we call "water", while the solid form we call "ice", and the gas form we call "water vapor". Water vapor is colorless, odorless, and invisible. But you sure can FEEL it on a hot and humid day! \n\nNext, do you remember the last time you encountered some fog? Think about what IT looked like. If you looked real close, you would have seen zillions of tiny tiny droplets of water floating in the air. And, if you remember the last time you saw some steam, you might think that it looked just like fog (except it was hotter). Steam is NOT pure water vapor! \n\nWell, it happens that the description, "zillions of tiny tiny droplets of water floating in the air", applies to every fog, to every mist, to every burst of steam -- and to every cloud in the sky. If you sit back and simply watch the clouds for a while, you will see that some clouds grow, some shrink, and some do nothing but move across the sky. What is happening to the growing or shrinking clouds? When a cloud grows, water vapor in the air gradually "condenses" to form lots more tiny tiny droplets. When a cloud shrinks, many droplets are completely "evaporating" to become invisible water vapor. \n\nAs the winds move air across the sky, carrying clouds along, fragments of wind known as "eddys" can do strange things to the shapes of clouds. A common game is to study a cloud's shape and guess what it looks like. Also, winds from different directions can collide with each other, which often has great effects upon clouds. It depends on how cold or warm the colliding winds are, and how much water each wind carries (only the differences matter, not whether the water is in the form of vapor or tiny drops). \n\nFor rain to happen, the weather conditions inside the clouds, and surrounding them, has to cause the droplets to grow. Some droplets will grow by colliding and combining with each other -- just what you Asked about. Some droplets will grow by acquiring more and more water vapor from the air. Some will do both. But the important thing to remember now is that MOST of the droplets in the clouds grow at the same time! \n\nBUT, the droplets do not all grow at the same rate; some grow faster than others. As soon as ANY get big enough, they start to fall out of the cloud. Water is heavier than air, after all. Depending on the wind conditions, those first raindrops might be blown back up into the cloud, where they can grow some more. Eventually, however, they get too big to stay up in the air, so they fall all the way to the ground. And the slower-growing droplets will fall after them, and the slower-growing-yet droplets will fall after THEM, and so on. This is the essence of the raining process. \n\nAs I said at the start, there are a couple of reasons why the raindrops don't combine to make a single stream. The first reason is simply that raindrops start falling just as soon as they are too heavy to stay in the air. The second reason is that they are all falling together DOWNWARDS, not sideways. If the wind blows them sideways, they all move TOGETHER sideways. That isn't good enough to cause them to meet each other, while falling, so they could combine to form a si
548046
To an extent it is true.  If dew has settled by morning, then that means there is less water vapor in the air.  If there is less water in the air, then it is less likely to condensate and fall.  However, after dew has settled, if it gets cold enough, it can still rain.
422900
My guess is that they can get bigger during a storm. I think the reason is this:\nWhen a storm is brewing, the warm and cold air cause the clouds to vibrate and the moisture in the rain-clouds begins to 'rub together' so crazily that it creates it's own electricity (just like when you rub a balloon on your head briskly, and then it will stick to the wall for a while, due to the static electricity created)and then comes the lightning - when the static gets too much...it needs to release itself and the only place is EARTH. This sudden release of a high-voltage charge will no doubt cause the cloud to dissipate - thus making a huge downpour of rain...and with larger RAINDROPS!
364366
As air rises to get over the mountain, it cools.  Cooler air can't carry as much water vapor as warmer air, so cloud droplets form.
353678
The water droplets are very tiny and present a lot of surface area (compared to their volume) to the air. Rapid evaporation from the surface of the droplets cools them sufficiently to freeze.
1157155
A given cell of a thunderstorm goes through three stages: the cumulus stage, the mature stage, and the dissipation stage.\n\nIn the cumulus stage of a thunderstorm cell, masses of moisture are pushed upwards. The trigger for this can be solar insolation heating the ground producing thermals, areas where two winds converge forcing air upwards, or where winds blow over areas of high ground. The moisture rapidly cools into liquid drops of water, which appears as cumulus clouds. As the water vapour condenses into liquid, latent heat is released which warms the air, causing it to become less dense than the surrounding dry air, and so the air will tend to rise in an updraft due to the process of convection (hence the term convective precipitation). This creates a low-pressure zone beneath the forming thunderstorm. In a typical thunderstorm, some 5×108 kg of water vapour are lifted and the amount of energy released when this condenses is about equal to the energy used by a city (US-2002) of 100,000 during a month.\n\nIn the mature stage, the warmed air continues to rise until it reaches existing air which is itself warmer, and the air can rise no further. Often this 'cap' is the tropopause. The air is instead forced to spread out, giving the storm a characteristic anvil shape. The resulting cloud is called cumulonimbus incus. The water droplets coalesce into heavy droplets and freeze to become ice particles. As these fall they melt, to become rain. If the updraft is strong enough, the droplets are held aloft long enough to be so large that they do not melt completely as they fall and fall as hail. While updrafts are still present, the falling rain creates downdrafts as well. The presence of both updrafts and downdrafts during this stage can cause considerable internal turbulence in the storm system, which sometimes manifests as strong winds, severe lightning, and even tornadoes. If there is little wind shear, the storm will rapidly 'rain itself out', but if there is sufficient change in wind speed and/or direction the downdraft will be separated from the updraft, and the storm may become a supercell.\n\nFinally, in the dissipation stage, updraft conditions no longer exist, and the storm is characterized largely by weak downdrafts. Because most of the moisture has precipitated out, there is not sufficient moisture in the lower air to sustain the cycle and the thunderstorm
1008382
Falling raindrops are often depicted in cartoons or anime as "teardrop-shaped" — round at the bottom and narrowing towards the top — but this is incorrect. Only drops of water dripping from some sources are tear-shaped at the moment of formation. Small raindrops are nearly spherical. Larger ones become increasingly flattened on the bottom, like hamburger buns; very large ones are shaped like parachutes. [1]  The shape of raindrops was studied by Philipp Lenard in 1898. He found that small raindrops (less than about 2 mm diameter) are approximately spherical. As they get larger (to about 5 mm diameter) they become more doughnut-shaped. Beyond about 5 mm they become unstable and fragment. On average, raindrops are 1 to 2 mm in diameter. The biggest raindrops on Earth were recorded over Brazil and the Marshall Islands in 2004 — some of them were as large as 10 mm. The large size is explained by condensation on large smoke particles or by collisions between drops in small regions with particularly high content of liquid water.\n\nand they obviously fall at the speed of gravity
492491
Water vapor is transparent (for most purposes) and so mere humidity in the atmosphere can't be a cloud. Since clouds don't have motors keeping them in the air, and yet stay there for hours in some cases, they can't be solid, for if they were, they'd fall out of the sky and we'd find cloud bits laying around on the ground. And the same is true for liquid as well. \n\nSo what's a cloud? Mostly, it's very small bits, so small that air currents can keep them in the air. The bits can be solid (eg, ice crystals of which snowflakes are examples), or liquid (eg, little drops of water, of which rain is an example). In either case, enough of these small things begin to look white as light passes thorough them and is reflected and refracted and generally diverted. Kind of like the effect of fine particulate suspensions in water. They are sometimes referred to as milky looking. Indeed, milk is white for a similar reason.\n\nThese are usually formed around dust bits, for real. High humidity (forced by cooling temperatures) produces supercooling (ie, ready to condense, if a trigger can be found). The dust motes provides the trigger. With updraft winds, a condensed drop can grow pretty large. And if it goes high enough, and gets cold enough, the drop can freeze (and thus make hail). If the orignal condensation is sufficiently cold, then water will be added to an ice crystal. With the proper history, such crystals become snowflakes.
1062646
Rain, rain, don't go away.\nLet's catch some drops and save some water.
420266
Usually underground wires are surrounded by lots of insulation. Plus, the ground itself is an insulator. So even if it does get wet, the power won't go very far. Then there is the fact that a wire is just a wire. Wires do not really short out from water. It is the devices they connect that short out.
467833
In some countries, they spray the top of the clouds ("seed the clouds") with chemicals (AgI or AgCl).  This causes the small water droplets in the cloud to grow, and finally the drops are big and heavy enough to fall to the ground in the form of rain.\n\nThe reason for doing this could be that you really don't want rain in a certain area, and you think it is a better idea to make the potential rain clouds "release the rain" in another area, before they have moved with the wind to the area you want to protect.\n\nSo, the rain is not really artificial, but the cause of the rain is artificial.
307686
If you think about it, the "source" of a river is not a real thing; It's just a single spot in the water cycle. Rain falls, collects, runs into streams, runs into rivers, run to a lake or an ocean, evapourates into clouds, and goes round again.  You could argue that anywhere in this cycle is a starting point, or nowhere.  Gravity & evapouration are driving this cycle.  In the same way, winds are just air moving from an area of higher pressure to an area of lower pressure. What causes these differences in pressure is what starts the winds a-blowing.  Some of the factors involved are temperature changes in the oceans, and the friction of the atmosphere against the earth as it turns.
1147858
Two forces act on a raindrop. One is gravity which is constant, the other is the friction from the air, which is opposed to gravity. The latter is proportional to the speed of the drop and the surface area.\nDuring it´s fall the speed increases and therefore the drag. In the end the two force are equal and the drop continues to fall with constant speed.
36815
From the National Weather Service:\n\nWhen we talk about rainfall, we usually refer to it as being either showers or rain. If we are forecasting showers, we expect the rain to fall on an intermittent basis and from cumulus-type clouds. The showers may vary greatly in intensity over just a few minutes or a few miles. For example, lets say that the forecast for today is calling for a chance of showers. That means that if the rain does develop, it will be on and off, rather scattered, may vary in intensity over just a couple of minutes, and fall from cumulus-type clouds.\n\nIf the forecast for today called for rain, it means we expect the rain to fall rather steadily and from a flat, stratus-type of cloud, and won't change much in intensity from hour to hour. It also means that the rain will fall over a fairly large area, not like showers, which usually fall over smaller areas.
51376
It depends on a number of variables. One factor is the temperature difference between two air masses. The warm air will hold more water than cold air, so if a warm front hits a very cold air mass the cold air will cool the warm air and it will become oversaturated with water vapor. The more the warm air is cooled the more rain will fall. \n\nAnother factor is the way the air masses are moving. If a warm front moves over cold air slowly it will form a gradual transition with the cold air remaining near the ground and the warm air climbing gradually over it. This will produce a prolonged period of rain. If a cold front pushes under a warm air mass it may form a much steeper boundary area between the two air masses. This can produce very hard short periods of rain. \n\nHere's a little diagram:\nhttp://www.tiscali.co.uk/reference/encyclopaedia/hutchinson/m0006324.html
922889
Because air at ground level and a significant distanace above is rarely saturated - when it is, fog forms - which is a cloud on the ground. It has to be saturated a significant distance above ground or else you only get shallow areas of ground fog or dew/frost (if it is unsaturated say 50-200 feet above ground).\n\nBases of what we normally consider to be clouds rarely touch the ground because rising air motion is required to saturate the air and form the cloud. If it has to rise to do that, it cannot occur on the ground - though such clouds can be advected to a higher location and perhaps reach ground level there - or as is more common, the rising motion occurs up a slope with a cloud forming at some point along it.
1034117
no clouds are not solid they are made  up of water  vapor and gas. Clouds are formed when air contains as much water vapor (gas) as it can hold. This is called the saturation point, and it can be reached in two ways. First, moisture accumulates until it reaches the maximum amount the volume of air can hold. The other method reduces the temperature of the moisture filled air, which in turn lowers the amount of moisture it can contain. Saturation, therefore, is reached through evaporation and condensation, respectively. When saturation occurs, moisture becomes visible water droplets in the form of fog and clouds.\n\nIt should be noted that condensation by itself does not cause precipitation (rain, snow, sleet, hail). The moisture in clouds must become heavy enough to succumb to gravity and return to earth's surface. This occurs through two processes. In cold clouds ice crystals and water droplets exist side by side. Due to an imbalance of water vapor pressure, the water droplets transfer to the ice crystals. The crystal seventually grow heavy enough to fall to earth. In the second process, water droplets in warm clouds collide and change their electric charge.Droplets of unlike charge attract one another and merge, thereby growing until they have sufficient weight to fall.\n\nThere is no difference between fog and clouds other than altitude. Fog is defined as a visible moisture that begins at a height lower than 50 feet. If the visible moisture begins at or above 50 feet, it is called a cloud. Two common types of fog are called radiation fog and advection fog. Radiation fog forms during the night as the earth's surface cools and the air immediately above it cools in turn by conduction. If the air is moist enough, the cooling causes it to reach saturation and visible water droplets form. We often call this type of fog ground fog because it lies so close to the surface. Advection fog forms when warm moist air moves over a colder surface (advection means to move horizontally). A perfect example is on the west coast of continents. Prevailing westerly winds move moist air from over a warm ocean area to over the colder waters off the coast. Fog forms and is carried by the westerly over the land.\n\nClouds can form anywhere in the troposphere, and although condensed liquid, they are light enough to float in the air and move from place to place by the wind. Clouds are classified according to appearance and height. Based on appearance, there are two major types: Clouds of vertical development, formed by the condensation of rising air; and clouds that are layered, formed by condensation of air without vertical movement. When clouds are classified by height, there are four classes: high, middle, low, and vertical development.\n\nCloud names, of which there are twelve, combine appearance and height. A brief description of the root name will indicate this combination of features.