Shape of raindrops?

[Endercreeper01]

Why are raindrops shaped the way they are?

[Sensei]

Raindrops don't look as everybody thinks they look like (it's rather shape of drops from faucet).

In Discovery Channel there was program in which they're showing everything at 1000 fps-10k fps, and it revealed true shape of raindrops.

They were flattened disks in Y axis, or rings with hole mostly.

[Endercreeper01]

Yes, but why would they be the shape as shown in discovery channel?

[dimreepr]

The property of water called hydrogen bonding determines the shape of raindrops, this from Wikipedia:

"The charge differences cause water molecules to be attracted to each other (the relatively positive areas being attracted to the relatively negative areas) and to other polar molecules. This attraction contributes to hydrogen bonding, and explains many of the properties of water"

 

 

 

Edit/ Also the reason for water tension.

Edited December 25, 2013 by dimreepr

[Endy0816]

Air resistance along with that.

[Sensei]

Yes, but why would they be the shape as shown in discovery channel?

 

They looked like parachute, that later ripped apart.

Some were filled with air inside and looked like water balloon (empty inside) and then tear apart.

Really small raindrops after ripping apart, disappeared immediately changing to vapor, and didn't reach ground.

 

To verify "why they look like they look" we would need to investigate how other fluids looks like when they're "sprayed" from at least couple meters height in large quantity, and recording them with high speed camera 1k+ fps with large zoom.

f.e. pure methanol, ethanol

These two don't have so strong hydrogen bond as water, and have significantly smaller boiling temperature (so theoretically should easier vaporize after being sprayed)

[dimreepr]

Air resistance along with that.

 

Indeed, the shape of a raindrop is actually size dependant. At 1mm the drop is falling slower and wind resistance is negligible so the drop is spherical but as the drop size increases so does its speed and wind resistance starts to play a more significant role and the shape of the drop becomes bun shaped and larger still the drop starts to resemble a parachute, at this stage the drop becomes unstable, from memory 3/4mm, and tends to break up into many droplets which are again spherical.

 

My apologies for the brevity of my previous post, I ran out of time.

 

Edited December 27, 2013 by dimreepr