nowhere of water droplets?

[insight]

Originally Posted by cwes99_03

Not to single you out, but everyone on this site, myself included needs to read their posts before posting to check on their gramar and spelling.

Convection can't occur in a vaccuum. That being said, we are talking about convection in zero g, not a vaccuum. Zero g occurs within the space ship, where the pressure of the air is maintained, not lower. If the air were to be less dense, or under pressurized, then the water-vapor level in the air would be able to be oversaturated when one introduces a large amount of water to it from a sealed vessel (some of it would instantly vaporize.) But this is off thread.

Explain what you mean by relative humidity level within the droplet boundary, because if you are within the boundary, we don't talk about humidity, we talk about disolved gases.

Firstly, i'm not in the droplet boundary. I'm outside it and see where it goes.

[Boerseun]

Originally Posted by insight

Convection is nothing to do with gravity. As long as there is air to be transfered heat, convection takes place. Gravity pulls the air. If there is no gravity, there is no air and the convection also never happens. the density of air is lower in zero g, which interns to oversize the water doplet volume and the overall relative humidity ratio within the droplet boundary maintains.

No, convection has everything to do with gravity.
When something heats up, it expands. When it expands, it becomes more bouyant. Bouyancy causes the heated liquid/gas/whatever to rise, seeing as it is 'pressed away' by the less-bouyant cold stuff.
In a zero-g environment, there's no such thing as bouyancy - bouyancy being mediated, of course, by gravity.
Thus - in a zero-g environment, convection simply cannot happen. Diffusion will happen, but that's got to do with gas pressure, pressure not being dependent on gravity.

[Jay-qu]

I think it is funny how people have been throwing around the idea of 'tear drop' shaped when a tear drop is a drop of water(although its slightly saline)... lol

[HydrogenBond]

If air was saturated with water vapor and was cooled further, the hydrogen bonding potential between the water molecules would be able to lower and the water would condense as tiny droplets. The smaller the droplet the higher the surface tension. The surface tension is also connected to hydrogen bonding on the perimeter; hydrogen than can not fully lower potential. The push would be to lower surface tension by the droplets combining to form less surface area per liquid volume. The water would also condense on surfaces that offer electrons to share as a way to lowering hydrogen bonding potential and surface tesion. The minimum potential shape would be a function of temperature and the surfaces present.

[UncleAl]

Hey git - fog, clouds.

[CraigD]

Originally Posted by insight

… Actually when water droplets fall down, they aren't spherical. The gravity's pull transforms the spherical shapes into eye-drop shapes …

This is a common misperception, owing to the fact that water droplets have this shape on flat surfaces such as window panes, where we usually see them. It’s practically impossible to see a falling raindrop with the naked eye.

While falling, they’re actually shaped like a thick hamburger patty or pancake (see http://ga.water.usgs.gov/edu/raindropshape.html). Even sites like these don’t, I think, have the shapes quite right – actual photos of raindrops I’ve seen look more like this.

[insight]

Originally Posted by CraigD

This is a common misperception, owing to the fact that water droplets have this shape on flat surfaces such as window panes, where we usually see them. It’s practically impossible to see a falling raindrop with the naked eye.

While falling, they’re actually shaped like a thick hamburger patty or pancake (see http://ga.water.usgs.gov/edu/raindropshape.html). Even sites like these don’t, I think, have the shapes quite right – actual photos of raindrops I’ve seen look more like this.

That's enlightening, thanks Craig. Totally different story!

[cwes99_03]

The shape of the drop is directly related to at least three things that I can think of. 1) Relative velocity of the falling drop in respect to the surrounding molecules of air. 2) Volume of the rain drop (which of course depends upon the pressure exerted on the drop by the surrounding molecules. 3) the chemical makeup of the drop (salinity, soluble gasses, etc.)

Now instead of talking about the shape, we are talking about the transformation of drops as they fall. There are in fact many shapes that the drop transitions through as it falls dependent upon the variables mentioned above and possibly others i'm not considering.

[CraigD]

Originally Posted by cwes99_03

… Now instead of talking about the shape, we are talking about the transformation of drops as they fall. There are in fact many shapes that the drop transitions through as it falls dependent upon the variables mentioned above and possibly others i'm not considering.

Indeed.

The basic picture I get from following links such as the above is one of large drops flattening until they form a “parachute shape” with most of their mass around its rim, which then breaks up into smaller, slower-falling drops, which collide with and are absorbed by other large and small drops, producing large drops that flatten into the parachute shape, etc. A wonderful sequence!

It’s frustrating that, for all our video recording capabilities, water droplets remain very difficult to see, so, while we can visualize this process, we can’t easily see it actually occurring. If I’m judging a science fair project and come across a project than manages to video raindrops, I’m giving it a prize, even if its methodology’s a mess!

[Jay-qu]

I understand that rain drops can take a few different shapes - but not perfectly sphereical ones. So my question is why do we get round hail?