# I've looked at clouds for sometime now ... **URL:** \ **Category:** Factual Questions\ **Created:** [March 29, 2016, 7:50am UTC](https://boards.straightdope.com/t/ive-looked-at-clouds-for-sometime-now/750507 "2016-03-29T07:50:09Z")\ **Posts on this page:** 19\ **Page:** 1
**Author:** ![Medici](https://avatars.discourse-cdn.com/v4/letter/m/85f322/32.png) [@Medici](https://boards.straightdope.com/u/Medici)\ **Post date:** [March 29, 2016, 7:50am UTC](https://boards.straightdope.com/t/ive-looked-at-clouds-for-sometime-now/750507/1 "2016-03-29T07:50:09Z")
Why, almost as a contradiction in terms, are some clouds hard-edged? ---
**Author:** ![Richard\_Pearse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/richard_pearse/32/13144_2.png) [@Richard\_Pearse](https://boards.straightdope.com/u/Richard_Pearse)\ **Post date:** [March 29, 2016, 8:31am UTC](https://boards.straightdope.com/t/ive-looked-at-clouds-for-sometime-now/750507/2 "2016-03-29T08:31:43Z")
A defined boundary between the saturated air and the unsaturated air, sometimes due to the saturated air being pushed up by convection currents. In reality even the well defined ones aren’t all that well defined when you get up close. ---
**Author:** ![Derleth](https://avatars.discourse-cdn.com/v4/letter/d/b9e5f3/32.png) [@Derleth](https://boards.straightdope.com/u/Derleth)\ **Post date:** [March 29, 2016, 8:35am UTC](https://boards.straightdope.com/t/ive-looked-at-clouds-for-sometime-now/750507/3 "2016-03-29T08:35:01Z")
> [@Medici](#): > > Why, almost as a contradiction in terms, are some clouds hard-edged? Let’s take it from some people who’ve looked at them from both sides, the [the scientists at _Scientific American_](http://www.scientificamerican.com/article/why-do-clouds-always-appe/): > [@Harvey Wichman of Claremont McKenna College](#): > > "A good analogy for cloud formation is the development of bubbles of steam on the bottom of a kettle. Some spots are slightly hotter than others; it is at these locations that the water is turned to vapor. When a bubble gets large enough, the water’s surface tension can no longer hold it, and so it rises. Fluids having different densities behave quite independently. The bubble stays a bubble all the way to the top where it breaks free as steam. > > "So, too, with clouds. A spot on the earth’s surface gets hotter than the surrounding area. An example would be the black, flat tarred roof of a large building or a vacant parking lot. The air above it heats up and forms a bubble of hot air, which is less dense than the surrounding air. When the surface tension can no longer hold it, the bubble breaks free and rises. This is why soaring birds such as hawks and eagles are always circling–they sense an updraft and keep turning to stay inside the bubble of rising air. The hot air ascends until it reaches an altitude where the temperature is cool enough to condense the water vapor contained in the air bubble into visible droplets. The visible droplets become a cloud, and that altitude (temperature) at which it forms is called the condensation level. > > “There can be some mixing of clouds on windy days, but in general the air mass at the cloud level is moving quite steadily. And again, fluids of slightly different densities do not mix well. This tendency not to mix accounts for one of the most familiar types of weather systems. When a cold front (a mass of cool, dense air) bumps into a warm air mass, it runs underneath the warm air mass and pushes all the warm air up. When that warm air reaches the condensation level, you get a solid cloud mass and rainy weather.” So clouds keep a straight edge because they don’t even think about speed. It’s just something they don’t need. [If you think you don’t understand clouds at all, you can always use the HOLODEC](http://www.npr.org/2015/10/02/444877155/whats-at-the-edge-of-a-cloud) with Raymond Shaw, an atmospheric scientist at Michigan Technological University. (This is utterly gratuitous, but cool.): > [@](#): > > His team has been flying through clouds in an airplane equipped with a new instrument that they call the Holographic Detector for Clouds, or HOLODEC. > > “The instrument creates a small, three-dimensional picture of everything inside of a volume,” says Shaw. > > The volume isn’t a big amount of space — it’s like a cigar-sized section of the cloud — but it’s enough to be revealing. > > “We can not only see how many droplets there are, and how big they are, we can also see how they are distributed in space,” explains Shaw. > > They focused on the clouds’ edges — where dry air is mixing in. You might think all the droplets at the edge of a cloud would evaporate a little bit and that they would all shrink. But that’s not what happens. > > Shaw says dry air seems to creep in and evaporate some droplets completely, while others survive in wispy cloud filaments surrounded by clear air. > > “The droplets that are remaining are just as big as the droplets that are in the center — kind of the protected core of the cloud, where no evaporation has taken place,” he says. “That was a surprise to us.” When asked about the suggestive shape of the region captured in the HOLODEC, he said “Sometimes a long, oblong shape is just something to study intently.” ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [March 29, 2016, 12:16pm UTC](https://boards.straightdope.com/t/ive-looked-at-clouds-for-sometime-now/750507/4 "2016-03-29T12:16:26Z")
Wow. I really don’t know clouds. At all. ---
**Author:** ![Si\_Amigo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/si_amigo/32/2877_2.png) [@Si\_Amigo](https://boards.straightdope.com/u/Si_Amigo)\ **Post date:** [March 29, 2016, 12:35pm UTC](https://boards.straightdope.com/t/ive-looked-at-clouds-for-sometime-now/750507/5 "2016-03-29T12:35:05Z")
I believe its clouds illusions you are recalling. ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [March 29, 2016, 12:59pm UTC](https://boards.straightdope.com/t/ive-looked-at-clouds-for-sometime-now/750507/6 "2016-03-29T12:59:58Z")
A lot of the feathery cirrus-type clouds have soft-looking edges because of _virga_; that is to say, ice crystals fall out of the bottom of the cloud and sublime gradually on the way down. If you manage to see these clouds in three dimensions (from both sides, that is) you might notice the tail of virga precipitation falling downwards into the wind. [![](https://beccasbyline.files.wordpress.com/2012/05/cirrus-clouds-1_28018101.jpg) ](https://beccasbyline.files.wordpress.com/2012/05/cirrus-clouds-1_28018101.jpg) ---
**Author:** ![bienville](https://avatars.discourse-cdn.com/v4/letter/b/4bbf92/32.png) [@bienville](https://boards.straightdope.com/u/bienville)\ **Post date:** [March 29, 2016, 1:06pm UTC](https://boards.straightdope.com/t/ive-looked-at-clouds-for-sometime-now/750507/7 "2016-03-29T13:06:02Z")
_ENOUGH!!!_ Now that we’ve looked at clouds from both sides, can we get on to addressing the question of clouds in my coffee? That’s _my_ question! I’m sure you all find my question much more interesting. Let’s all address my question about clouds in my coffee. _My_ question is what this Thread is really about. This Thread is about _MEEEEEEEEEEEE!!!_ ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [March 29, 2016, 1:17pm UTC](https://boards.straightdope.com/t/ive-looked-at-clouds-for-sometime-now/750507/8 "2016-03-29T13:17:38Z")
Please note that we have not covered the way they appear from up and down yet. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [March 29, 2016, 1:26pm UTC](https://boards.straightdope.com/t/ive-looked-at-clouds-for-sometime-now/750507/9 "2016-03-29T13:26:34Z")
Obligatory [XKCD reference.](https://xkcd.com/941/) ---
**Author:** ![Si\_Amigo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/si_amigo/32/2877_2.png) [@Si\_Amigo](https://boards.straightdope.com/u/Si_Amigo)\ **Post date:** [March 29, 2016, 2:20pm UTC](https://boards.straightdope.com/t/ive-looked-at-clouds-for-sometime-now/750507/10 "2016-03-29T14:20:57Z")
> [@bienville](#): > > _ENOUGH!!!_ > Now that we’ve looked at clouds from both sides, can we get on to addressing the question of clouds in my coffee? > That’s _my_ question! I’m sure you all find my question much more interesting. Let’s all address my question about clouds in my coffee. _My_ question is what this Thread is really about. This Thread is about _MEEEEEEEEEEEE!!!_ You probably think this thread is about you, don’t you? Don’t you? That would be so vain about you if you did. ---
**Author:** ![Sunspace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunspace/32/1250_2.png) [@Sunspace](https://boards.straightdope.com/u/Sunspace)\ **Post date:** [March 29, 2016, 2:46pm UTC](https://boards.straightdope.com/t/ive-looked-at-clouds-for-sometime-now/750507/11 "2016-03-29T14:46:31Z")
> [@Machine\_Elf](#): > > Obligatory [XKCD reference.](https://xkcd.com/941/) Oh, that is _beautiful_. ---
**Author:** ![Washoe](https://avatars.discourse-cdn.com/v4/letter/w/ecae2f/32.png) [@Washoe](https://boards.straightdope.com/u/Washoe)\ **Post date:** [March 29, 2016, 2:47pm UTC](https://boards.straightdope.com/t/ive-looked-at-clouds-for-sometime-now/750507/12 "2016-03-29T14:47:52Z")
> [@bienville](#): > > _ENOUGH!!!_ > Now that we’ve looked at clouds from both sides, can we get on to addressing the question of clouds in my coffee? > That’s _my_ question! I’m sure you all find my question much more interesting. Let’s all address my question about clouds in my coffee. _My_ question is what this Thread is really about. This Thread is about _MEEEEEEEEEEEE!!!_ I don’t know quite how to break this to you, but you don’t put marshmallows in coffee. You put them in _hot chocolate_. But then again, if you’re wealthy enough to fly your personal Learjet any old place just to take in a good solar eclipse, you can put whatever the fuck you want in your coffee. ---
**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\ **Post date:** [March 29, 2016, 2:58pm UTC](https://boards.straightdope.com/t/ive-looked-at-clouds-for-sometime-now/750507/13 "2016-03-29T14:58:37Z")
At the heart of every cloud droplet is a little piece of plant semen … so yeah, you can put whatever you want into your coffee. ---
**Author:** ![D18](https://avatars.discourse-cdn.com/v4/letter/d/c57346/32.png) [@D18](https://boards.straightdope.com/u/D18)\ **Post date:** [March 29, 2016, 3:00pm UTC](https://boards.straightdope.com/t/ive-looked-at-clouds-for-sometime-now/750507/14 "2016-03-29T15:00:01Z")
> [@bienville](#): > > _ENOUGH!!!_ > Now that we’ve looked at clouds from both sides, can we get on to addressing the question of clouds in my coffee? > That’s _my_ question! I’m sure you all find my question much more interesting. Let’s all address my question about clouds in my coffee. _My_ question is what this Thread is really about. This Thread is about _MEEEEEEEEEEEE!!!_ Alright, took some googling and connecting the dots of the pop-culture background, but that was pretty damn funny. Well played, sir. Well played. ---
**Author:** ![motu](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/motu/32/259_2.png) [@motu](https://boards.straightdope.com/u/motu)\ **Post date:** [March 29, 2016, 4:21pm UTC](https://boards.straightdope.com/t/ive-looked-at-clouds-for-sometime-now/750507/15 "2016-03-29T16:21:42Z")
> [@bienville](#): > > _ENOUGH!!!_ > Now that we’ve looked at clouds from both sides, can we get on to addressing the question of clouds in my coffee? > That’s _my_ question! I’m sure you all find my question much more interesting. Let’s all address my question about clouds in my coffee. _My_ question is what this Thread is really about. This Thread is about _MEEEEEEEEEEEE!!!_ Damn you Bienville! First, just reading your post got that song going through my head but I just was in a co-worker’s office and it came on the radio. It’s going to take me a week to get this outta my head! ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [March 29, 2016, 7:38pm UTC](https://boards.straightdope.com/t/ive-looked-at-clouds-for-sometime-now/750507/16 "2016-03-29T19:38:40Z")
> [@Sunspace](#): > > Oh, that is _beautiful_. You can get a similar effect with [a low-tech solution.](http://eyestilts.com/intro.html) I’ve been wanting to do something like that for a while now. ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [March 29, 2016, 7:42pm UTC](https://boards.straightdope.com/t/ive-looked-at-clouds-for-sometime-now/750507/17 "2016-03-29T19:42:32Z")
> [@Machine\_Elf](#): > > You can get a similar effect with [a low-tech solution.](http://eyestilts.com/intro.html) I’ve been wanting to do something like that for a while now. I’ve been taking enhanced 3D pictures for quite a while now by moving 5 feet or more between exposures. It makes the parallax quite a bit larger, and even things that ought to be 3D appear in more extreme relief (You can use a special “3D viewer”, like a stereopticon, or you can simply use the “crossed eye” method, with no special device. ) ---
**Author:** ![smithsb](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/smithsb/32/12107_2.png) [@smithsb](https://boards.straightdope.com/u/smithsb)\ **Post date:** [March 29, 2016, 9:53pm UTC](https://boards.straightdope.com/t/ive-looked-at-clouds-for-sometime-now/750507/18 "2016-03-29T21:53:25Z")
Judy Collins and Joni Mitchell I’ve looked at clouds for sometime now … [Joni Mitchell - Both Sides Now (HD) - YouTube](https://www.youtube.com/watch?v=aCnf46boC3I) ---
**Author:** ![Senegoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/senegoid/32/6606_2.png) [@Senegoid](https://boards.straightdope.com/u/Senegoid)\ **Post date:** [March 30, 2016, 4:18am UTC](https://boards.straightdope.com/t/ive-looked-at-clouds-for-sometime-now/750507/19 "2016-03-30T04:18:01Z")
Cumulus clouds (the big fluffy mostly-white ones that look like mountains of cotton candy) often have fairly flat, more-or-less sharply defined bottoms. They are puffy and fluffy on the sides and top. [Cumulus Clouds](https://eo.ucar.edu/webweather/cumulus.html). Notice the sort of flat bottom in the fourth picture. They tend to form over large fields or other areas where a warm patch of ground may form vertical updrafts, or thermals. Sailplane pilots especially look for cumulus clouds, and get directly below them and fly in tight circles (“thermaling”) to stay there, catching the updraft and gaining altitude. One result, of course, is if you’re not paying attention, you can get updrafted right into the cloud, where visibility is zero. This is not a good place for a glider to be. Especially if you’re flying out of the long-gone glider port at Fremont, Ca., which is right in the general flight area of both San Francisco Int’l Airport and Oakland Int’l Airport. The Big Jets have no qualms about flying right through those clouds if they happen to be in the way, and they aren’t expecting to find gliders there.