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Author Topic: What makes clouds float?  (Read 15974 times)

Offline The Scientist

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What makes clouds float?
« on: 31/12/2010 09:51:45 »
Can clouds support an average person's mass to prevent them from falling? What do you think? Thanks!


 

Offline Foolosophy

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What makes clouds float?
« Reply #1 on: 31/12/2010 10:26:59 »
Can clouds support an average person's mass to prevent them from falling? What do you think? Thanks!

Interesting question - ONCE AGAIN by THE Scientist

What sort of clouds are you referring to? (water droplets? Lead vapour? Uranium gas? Pressurised Chromium gas? An emulsion of methane and mercury droplets?)



What about this cloud?



« Last Edit: 31/12/2010 10:34:32 by Foolosophy »
 

Offline Soul Surfer

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What makes clouds float?
« Reply #2 on: 31/12/2010 11:08:37 »
Yes you can and it is done on a daily basis.  You need to be able to catch hold of the cloud and hold it in place using a fabric envelope.  It is called a hot air balloon.
 

Offline Foolosophy

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What makes clouds float?
« Reply #3 on: 31/12/2010 13:30:58 »
Yes you can and it is done on a daily basis.  You need to be able to catch hold of the cloud and hold it in place using a fabric envelope.  It is called a hot air balloon.

well done!

what about a Helium or Hydrogen filled balloon?

would that work too

Best Wishes

Foolosophy
 

Offline Airthumbs

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What makes clouds float?
« Reply #4 on: 31/12/2010 18:26:54 »
What about a cloud of lead?
 

Offline CliffordK

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What makes clouds float?
« Reply #5 on: 31/12/2010 21:54:25 »
I don't think I'll try walking on any clouds...   

I suppose you have 2 questions here.

"What makes a cloud float"
"Can it support additional mass"

I must admit that clouds are somewhat bizarre.  And, one wouldn't think that drops of water should be able to hang in the sky like they seem to do.

I think the formation of clouds is based on the "Ideal Gas Law"...  This is a Science Forum after all.

     pV = nRT

This essentially says that the volume of a gas is independent of the molecular weight, and thus the density of a gas is proportional to the molecular weight.

Keep in mind that Oxygen and Nitrogen form dimers.  So, if we look at the molecular weights of Oxygen, Nitrogen, and Water, we get:

O2: 2x16 = 32
N2: 2x14 = 28
H2O:2x1+16 = 18

What you find is that the molecular weight, and thus the density of water vapor is much less than that of Oxygen and Nitrogen (air).

This, along with a relatively high vapor pressure of water would create an elevator effect evaporating water and raising it into the higher atmospheric levels.  As the vapor rises, it decreases the humidity at the surface, and more water evaporates.

However, the higher levels of the atmosphere are much cooler.

And, thus the water vapor condenses into water droplets.  And one gets clouds.  Even with two water molecules joining, and the droplet is heavier than air (Molecular weight 18+18=36).

Atmospheric pressures, and the ability for these droplets to separate and recombine would tend to make the clouds tend to hover in one place.  Too big of droplets, and one gets RAIN.

The balance where the cloud is in the sky wouldn't tend to support weight, and there is nothing to stand on.

However,
Next time you wish to go for a balloon trip.  Perhaps try a WATER BALLOON!!!
If you don't get off the ground quickly, perhaps heat it to 101°C.



 

Offline The Scientist

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What makes clouds float?
« Reply #6 on: 02/01/2011 13:12:34 »
Can clouds support an average person's mass to prevent them from falling? What do you think? Thanks!

Interesting question - ONCE AGAIN by THE Scientist

What sort of clouds are you referring to? (water droplets? Lead vapour? Uranium gas? Pressurised Chromium gas? An emulsion of methane and mercury droplets?)



What about this cloud?






Those two pictures are interesting. Thanks Foolosophy.
Well, I'd say a cloud in general. Those everyday clouds you see when the sky is bright and when there is no rain. I can't put it better myself, can you help? Thanks again!
Best Wishes and Happy New Year!
 

Offline Foolosophy

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What makes clouds float?
« Reply #7 on: 02/01/2011 13:23:07 »
....not sure if I can help you in any way

What do you think?

Yours Sincerely

Foolosophy
« Last Edit: 02/01/2011 13:28:51 by Foolosophy »
 

Offline Soul Surfer

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What makes clouds float?
« Reply #8 on: 02/01/2011 20:41:04 »
The air cools and the water condenses out but the act of condensing releases a  great deal of heat which also tends to reinforce the updraft. This is what creates the intense updraft  in thunderheads.
 

Online yor_on

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What makes clouds float?
« Reply #9 on: 02/01/2011 23:04:37 »
What makes clouds float?

I would have liked to answer "Small pink teddy bears throwing fairy-dust" but as I know that that isn't the correct scientific terminology I will refrain from it. But if we name those creatures 'density'?

'Density' makes them float :)
 

Offline Foolosophy

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What makes clouds float?
« Reply #10 on: 03/01/2011 06:02:45 »
What makes clouds float?


'Density' makes them float :)

"Density" is not the reason that clouds float
 

Offline CliffordK

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What makes clouds float?
« Reply #11 on: 03/01/2011 06:15:51 »
The air cools and the water condenses out but the act of condensing releases a  great deal of heat which also tends to reinforce the updraft. This is what creates the intense updraft  in thunderheads.

Good point.
So the density of water vapor makes it float.  And, the act of condensing would also create an updraft to hold them up there.

And...  that would also explain how some areas can generate hailstones the size of a tennis ball.
 

Offline Foolosophy

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What makes clouds float?
« Reply #12 on: 03/01/2011 07:07:55 »
The air cools and the water condenses out but the act of condensing releases a  great deal of heat which also tends to reinforce the updraft. This is what creates the intense updraft  in thunderheads.

So the density of water vapor makes it float.  

Density is not the reason that clouds float
 

Online yor_on

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What makes clouds float?
« Reply #13 on: 03/01/2011 15:12:51 »
Density and buoyancy goes hand in hand.
But it depends on how you look at it.

So how do you look at it :)

"Condensation or deposition of water above the Earth's surface creates clouds. In general, clouds develop in any air mass that becomes saturated (relative humidity  becomes 100%). Saturation can occur by way of atmospheric mechanisms that cause the temperature of an air mass to be cooled to its dew point or frost point."

There are several nice links in the post too.
how air temperature, pressure, and density are related to cloud formation.

 

Online yor_on

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What makes clouds float?
« Reply #14 on: 03/01/2011 19:37:22 »
Apropos nothing, I think QC mentioned Gaia, or at least an equivalence, in an earlier thread discussing Earth. Now, that may seem as 'mumbo jumbo' but I found it quite fascinating. Take a look here The Gaia Hypothesis.
 

Offline QuantumClue

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What makes clouds float?
« Reply #15 on: 04/01/2011 12:52:57 »
Apropos nothing, I think QC mentioned Gaia, or at least an equivalence, in an earlier thread discussing Earth. Now, that may seem as 'mumbo jumbo' but I found it quite fascinating. Take a look here The Gaia Hypothesis.

I must protest. I was likening an understanding of biological processes to Mother nature, but I did state that I did not believe that Mother Nature truely was a decision making automaton like human beings are. I only said that sometimes it is difficult not run into language and personify nature as it reflects directly our natural beings.
 

Offline Foolosophy

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What makes clouds float?
« Reply #16 on: 04/01/2011 13:06:44 »
Density and buoyancy goes hand in hand.
But it depends on how you look at it.

So how do you look at it :)

"Condensation or deposition of water above the Earth's surface creates clouds. In general, clouds develop in any air mass that becomes saturated (relative humidity  becomes 100%). Saturation can occur by way of atmospheric mechanisms that cause the temperature of an air mass to be cooled to its dew point or frost point."

There are several nice links in the post too.
how air temperature, pressure, and density are related to cloud formation.



Density is not the reason that clouds float.

How can very fine particles remain suspended in air when they are clearly more dense than the air itself?

What is causing them to avoid settling out towards the ground?
 

Offline JP

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What makes clouds float?
« Reply #17 on: 04/01/2011 13:34:15 »
I agree with Foolosophy.  I don't see how density can be the cause, as ice and water droplets are more dense than air. 

The cause is that these droplets are tiny enough that updrafts in the atmosphere can hold them aloft.
 

Offline Foolosophy

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What makes clouds float?
« Reply #18 on: 04/01/2011 13:44:20 »
I agree with Foolosophy.  I don't see how density can be the cause, as ice and water droplets are more dense than air. 

The cause is that these droplets are tiny enough that updrafts in the atmosphere can hold them aloft.

thats a plausible explanation.

its like the fine dust particles that float around in the air.

Smoke particles have densities that are orders of magnitude greater than the surroudning air - but they are very fine. Why does a smoke plume behave the way it does?
 

Offline QuantumClue

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What makes clouds float?
« Reply #19 on: 04/01/2011 14:04:52 »
I agree with Foolosophy.  I don't see how density can be the cause, as ice and water droplets are more dense than air. 

The cause is that these droplets are tiny enough that updrafts in the atmosphere can hold them aloft.

I don't know the science behind clouds, but surely this explanation JP cannot sustain on its own. You'd be surprised how much water is really in the atmosphere waiting to condense...
 

Online yor_on

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What makes clouds float?
« Reply #20 on: 04/01/2011 18:27:48 »
what !!

Maybe :)
Keep on and I may, just may, change my mind..
But I want you to understand that our "Small pink teddy bears throwing fairy-dust" will have to go with that too. Are you really prepared to do that?


It's a cruel cruel world.
"Don't cry children, I'm sure the big meanies will change their mind now."
 

Offline Geezer

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What makes clouds float?
« Reply #21 on: 04/01/2011 19:54:22 »
I think the airmass that forms a cloud is quite dynamic, and this produces a mechanism that keeps the minute water particles aloft.

You may have noticed how the ride in an aeroplane suddenly gets rather bumpy as soon as it enters a cloud. I would think this is an indication how much turbulence there can be in clouds. However, that only just occurred to me, so I would not be very surprised to learn that it's wrong.
 

Offline QuantumClue

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What makes clouds float?
« Reply #22 on: 04/01/2011 20:28:56 »
I've had some time to study the science behind clouds. Clouds are as I suspected a gas phase, which as most of us will all know from elementary science is one of four well-known phases of matter. The gas phase is simply a water vapour, so it should be of no surprise clouds stay afloat. Eventually, this water vapour will condense - it is not condensed in the air, and is not kept afloat by any special mechanism, like which was mentioned perhaps ''droplets are tiny enough that updrafts in the atmosphere can hold them aloft'' - Droplets are not in this form in the sky - droplets occur when the gas phase changes into a liquid phase, and hence, which is why clouds condense into rain.
 

Offline QuantumClue

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What makes clouds float?
« Reply #23 on: 04/01/2011 20:41:57 »
Here's a little info courtesy of wiki ~ water vapour is in fact lighter than air. So air cannot keep water vapour afloat.
 

Offline CliffordK

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What makes clouds float?
« Reply #24 on: 04/01/2011 20:52:48 »
Density of water vapor (from my calculations above) is lighter than air, and is what gets single-molecule water vapor up into the air at the level of the clouds.  A very fine aerosol, while greater density than air, will tend to float in the air for some time, but slowly settles down.

(Quantum, remember, if density is lower than air, like hydrogen or helium, it will tend to rise, if it is heavier than air, like propane, it will tend to sink).

Condensation would tend to release heat (Soul Surfer) which would cause convection and updrafts.  

Condensation would also tend to cause a decrease in volume, and thus a decrease in pressure, and create more turbulence.

While we see clouds that leisurely float across the sky, my guess is that it is a much more dynamic process.  

For example, if clouds tend to form at 1000 feet due to high vapor density, and low temperatures, then as mentioned, that might tend to create some updrafts.  However, if the droplets fall down to 900 feet, the air temperature may be higher and the vapor density may be lower, and the falling droplets would evaporate back into vapor, which would cause a localized high pressure, and the now lighter than air vapor would tend to rise again up into the cloud, only to re-condense. 

As mentioned previously, not all clouds are created equally.  Thunderheads are likely much different from ordinary high floating clouds.  While not a meteorologist, I'm thinking that a thunderhead would be formed with very cold air combining with very humid air, with a more extreme gradient than normally experienced. 
« Last Edit: 04/01/2011 20:58:06 by CliffordK »
 

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What makes clouds float?
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