Naked Science Forum

Life Sciences => The Environment => Topic started by: paul.fr on 07/06/2007 10:20:31

Title: how fast does rain fall?
Post by: paul.fr on 07/06/2007 10:20:31

assuming there is no wind to make it go faster, how fast does rain fall?

Title: how fast does rain fall?
Post by: DoctorBeaver on 07/06/2007 11:25:56

If rain were to fall vertically, it would accelerate at 1g. You can work out the speed it would reach falling from different altitudes because I can't be bothered to.

Of course, you'd have to take into account wind speed, updraughts, air resistance etc to get an accurate answer.

Title: how fast does rain fall?
Post by: Bored chemist on 07/06/2007 20:02:29

I think you need the Stokes Einstien equation.
The terminal velocity of raindrops is pretty small- it depends on the size. Ignoring air resistance for a drop falling from a cloud would give a totally misleading answer so I won't bother either. Also this site
http://www.grow.arizona.edu/Grow--GrowResources.php?ResourceId=146
calculates it in a nice cute manner and does take drag into account.

Title: how fast does rain fall?
Post by: DoctorBeaver on 07/06/2007 20:04:35

Interesting little site  [:)]

Title: how fast does rain fall?
Post by: paul.fr on 07/06/2007 20:08:00

Quote from: Bored chemist on 07/06/2007 20:02:29

I think you need the Stokes Einstien equation.
The terminal velocity of raindrops is pretty small- it depends on the size. Ignoring air resistance for a drop falling from a cloud would give a totally misleading answer so I won't bother either. Also this site
http://www.grow.arizona.edu/Grow--GrowResources.php?ResourceId=146
calculates it in a nice cute manner and does take drag into account.

excellent, thanks BC  [:)]