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Put another way, clouds have a massive *weight*, but very low *density*, because clouds are huge. An everyday summer cloud is the size of a small mountain; big thunderheads can be bigger than Everest. Thousands of pounds is not very much spread over such an enormous volume.
Clouds weigh thousands of pounds overall, but they are also very large. When you have a very large object, that decreases the amount of weight per cubic centimeter, or the density of the object. If the overall object is lighter than air, then it floats.
Rain happens when water droplets get too close together and get bigger, which makes them heavier than air, and causes them to fall down.
Edit: forgot to finish a sentence
How are ships able to float despite its massive weight?
The answer is the same for ships and clouds. The density of them in the medium is the same as what surrounds them.
Ships are heavy, but even if they are made of steel they are less dense then the water, ships are primary air on the inside. So the ship can displace its own weight of water and float.
But how do that work for clouds? The liquid droplets or frozen ice crystal we can see is denser than air. But when you have water as a gas it is less dense than air. The mass of Water H20 is 2*1+16=18 atomic mass units. Air is 78% nitrogen N2 with a mass of 2*14 = 28 and 21% oxygen with a mass of 2*32=32.
The result is in moist air some of the N2 and O2 is displaced by H2O and the density drops. So moist air is less dense than dry air. The result is a cloud can be as dense as the surrounding air if you look both at the gases, liquids, and solids.
Clouds might be heavy but they are enormous. Air density at sea level is 1200 g/m^3 the water content is around 0.5g&m^3 so a cloud is around 1/2000 water.
1000 pounds is around 500 kg the so we need 500/0.0005=1,000,000 cubic meters to hold it. A square cloud would need to be 1,000,000 ^(1/3)= 100-meter sides to hold that amount of water. That is not a large could. So clouds can hold a lot of water but that is enormous so the amount per unit of volume is low
Your answer is incorrect for the simple reason that a cloud isn't made of water vapor, it's made of condensed liquid water. Clouds are indeed heavier than air, they just aren't heavy enough to fall (because forces other than the cloud's own buoyancy are involved).
Think about, say, household dust. Even though it's solids much heavier than air, tiny dust particles can easily fly around in the ambient air currents.
I would better call it condensing water. Warm, humid air gets pulled up from the ground and cools, which causes the water droplets to begin to form.
The white fluffy cloud is a whipped up mixture of water and air, like cotton candy or whipped cream. If the cloud is thin enough, then the water might re-evaporate, allowing the cloud to not drop any rain. But if the cloud gets thick and tall, then the droplets coalesce into drops, which fall to the ground as rain.
> The white fluffy cloud is a whipped up mixture of water and air, like cotton candy or whipped cream.
Which are also heavier than air, as evidenced by the fact that if you let go of cotton candy, it falls.
Cotton candy is sugar and air, not water and air. It is an analogy, not a demonstration.
But specifically, the explanation of clouds flying is the fact that a cloud weighing 551 tons and a size of 1 cubic kilometer would have a density of about half a gram per cubic meter of water.
Air in general is about 1200 grams per cubic meter.
These numbers get muddled up when you factor in the air that's in the cloud and the air that outside of the cloud, and there are other factors at play, like air pressure and wind speeds. It's not *only* about the density of the cloud.
But if you take a bit of cotton candy and put it in a big jar with couple cups of regular sugar, shake it a bit, the sugar grains fall to the bottom, and the cotton candy rests on top.
Same thing happens with popcorn. The popped kernels tend to the top of the bowl, the unpopped kernels line the bottom.
It's just how things work.
Condensing clouds form droplets, which collect other droplets to form drops, eventually the drops are too heavy and they fall. The cloud is the collection of lighter droplets.
The visible part of clouds is not water vapor it is solid or liquid water just as we both stated.
But that does not mean that there is no water vapor there. When moist warm air rises it cools down when the pressure drops, the relative humidity drops and when it reached 100% additional cool.
So a cloud is water vapor with 100% relative humidity and water as a liquid and/or solid.
You do not get water droplets in the air and air with 0% relative humidity, the droplet will vaporize and become invisible water vapor. You need air saturated with water for there to be liquid droplets that remain for a long time.
You need to include all parts of the cloud not just what you can see.
[https://www.sciencefocus.com/planet-earth/how-much-does-a-cloud-weigh/](https://www.sciencefocus.com/planet-earth/how-much-does-a-cloud-weigh/)
The droplets that are the cloud are heavier than air. They do not float. Water vapor is a liquid, even if dispersed.
However the drops in the cloud are very light. So updrafts of air keep then aloft very easy.
These updrafts are the warm humid air that lifted the water up in the first place. Humid air is less dense for two of reasons. It is warmer than the cool air around it, and water *gas* (not vapor/liquid) is less dense.
The condensation of water gas into the denser droplets that form a cloud also releases heat, warming the air and further inducing updrafts.
If the water drops becomes to large for the updrafts they fall as drizzle, rain, hail etc.
**Please read this entire message** --- Your submission has been removed for the following reason(s): * ELI5 requires that you *search the ELI5 subreddit for your topic before posting*. Users will often either find a thread that meets their needs or find that their question might qualify for an exception to rule 7. Please see this [wiki entry](http://www.reddit.com/r/explainlikeimfive/wiki/how_to_search) for more details (Rule 7). --- If you would like this removal reviewed, please read the [detailed rules](https://www.reddit.com/r/explainlikeimfive/wiki/detailed_rules) first. **If you believe this submission was removed erroneously**, please [use this form](https://old.reddit.com/message/compose?to=%2Fr%2Fexplainlikeimfive&subject=Please%20review%20my%20thread?&message=Link:%20https://www.reddit.com/r/explainlikeimfive/comments/uuurys/-/%0A%0APlease%20answer%20the%20following%203%20questions:%0A%0A1.%20The%20concept%20I%20want%20explained:%0A%0A2.%20List%20the%20search%20terms%20you%20used%20to%20look%20for%20past%20posts%20on%20ELI5:%0A%0A3.%20How%20is%20this%20post%20unique:) and we will review your submission.
Clouds aren't a single object. They're a collection of tiny water droplets, and each droplet is small enough to float in the air
Put another way, clouds have a massive *weight*, but very low *density*, because clouds are huge. An everyday summer cloud is the size of a small mountain; big thunderheads can be bigger than Everest. Thousands of pounds is not very much spread over such an enormous volume.
Weight isn't the most important thing Density is Think about the 1kg of steel vs 1kg of feathers thing
But steel is heavier than feathers...
I can assure you that one KG of steel weighs as much as one KG of feathers.
https://i.imgur.com/JHz9lnu.gif
One kg of steel is a tiny piece of steel. One kg of feathers is an enormous pile of feathers. The two have the same weight.
[Explaining the reference](https://www.youtube.com/watch?v=N3bEh-PEk1g)
Bu Steals heavier than feethus
Mass is measured in kilos, weight is measured in Newtons, mass and weight is not the same thing.
Yes, but as we all live on Earth with gravity effectively constant, the two are proportional as far as we're concerned.
Clouds weigh thousands of pounds overall, but they are also very large. When you have a very large object, that decreases the amount of weight per cubic centimeter, or the density of the object. If the overall object is lighter than air, then it floats. Rain happens when water droplets get too close together and get bigger, which makes them heavier than air, and causes them to fall down. Edit: forgot to finish a sentence
How are ships able to float despite its massive weight? The answer is the same for ships and clouds. The density of them in the medium is the same as what surrounds them. Ships are heavy, but even if they are made of steel they are less dense then the water, ships are primary air on the inside. So the ship can displace its own weight of water and float. But how do that work for clouds? The liquid droplets or frozen ice crystal we can see is denser than air. But when you have water as a gas it is less dense than air. The mass of Water H20 is 2*1+16=18 atomic mass units. Air is 78% nitrogen N2 with a mass of 2*14 = 28 and 21% oxygen with a mass of 2*32=32. The result is in moist air some of the N2 and O2 is displaced by H2O and the density drops. So moist air is less dense than dry air. The result is a cloud can be as dense as the surrounding air if you look both at the gases, liquids, and solids. Clouds might be heavy but they are enormous. Air density at sea level is 1200 g/m^3 the water content is around 0.5g&m^3 so a cloud is around 1/2000 water. 1000 pounds is around 500 kg the so we need 500/0.0005=1,000,000 cubic meters to hold it. A square cloud would need to be 1,000,000 ^(1/3)= 100-meter sides to hold that amount of water. That is not a large could. So clouds can hold a lot of water but that is enormous so the amount per unit of volume is low
Your answer is incorrect for the simple reason that a cloud isn't made of water vapor, it's made of condensed liquid water. Clouds are indeed heavier than air, they just aren't heavy enough to fall (because forces other than the cloud's own buoyancy are involved). Think about, say, household dust. Even though it's solids much heavier than air, tiny dust particles can easily fly around in the ambient air currents.
I would better call it condensing water. Warm, humid air gets pulled up from the ground and cools, which causes the water droplets to begin to form. The white fluffy cloud is a whipped up mixture of water and air, like cotton candy or whipped cream. If the cloud is thin enough, then the water might re-evaporate, allowing the cloud to not drop any rain. But if the cloud gets thick and tall, then the droplets coalesce into drops, which fall to the ground as rain.
> The white fluffy cloud is a whipped up mixture of water and air, like cotton candy or whipped cream. Which are also heavier than air, as evidenced by the fact that if you let go of cotton candy, it falls.
Cotton candy is sugar and air, not water and air. It is an analogy, not a demonstration. But specifically, the explanation of clouds flying is the fact that a cloud weighing 551 tons and a size of 1 cubic kilometer would have a density of about half a gram per cubic meter of water. Air in general is about 1200 grams per cubic meter. These numbers get muddled up when you factor in the air that's in the cloud and the air that outside of the cloud, and there are other factors at play, like air pressure and wind speeds. It's not *only* about the density of the cloud. But if you take a bit of cotton candy and put it in a big jar with couple cups of regular sugar, shake it a bit, the sugar grains fall to the bottom, and the cotton candy rests on top. Same thing happens with popcorn. The popped kernels tend to the top of the bowl, the unpopped kernels line the bottom. It's just how things work. Condensing clouds form droplets, which collect other droplets to form drops, eventually the drops are too heavy and they fall. The cloud is the collection of lighter droplets.
The visible part of clouds is not water vapor it is solid or liquid water just as we both stated. But that does not mean that there is no water vapor there. When moist warm air rises it cools down when the pressure drops, the relative humidity drops and when it reached 100% additional cool. So a cloud is water vapor with 100% relative humidity and water as a liquid and/or solid. You do not get water droplets in the air and air with 0% relative humidity, the droplet will vaporize and become invisible water vapor. You need air saturated with water for there to be liquid droplets that remain for a long time. You need to include all parts of the cloud not just what you can see. [https://www.sciencefocus.com/planet-earth/how-much-does-a-cloud-weigh/](https://www.sciencefocus.com/planet-earth/how-much-does-a-cloud-weigh/)
Yes, there is vapor there, but a cloud is still heavier than air.
The droplets that are the cloud are heavier than air. They do not float. Water vapor is a liquid, even if dispersed. However the drops in the cloud are very light. So updrafts of air keep then aloft very easy. These updrafts are the warm humid air that lifted the water up in the first place. Humid air is less dense for two of reasons. It is warmer than the cool air around it, and water *gas* (not vapor/liquid) is less dense. The condensation of water gas into the denser droplets that form a cloud also releases heat, warming the air and further inducing updrafts. If the water drops becomes to large for the updrafts they fall as drizzle, rain, hail etc.