# Naked Science Forum

## Life Sciences => The Environment => Topic started by: neilep on 22/03/2005 12:09:46

Title: How fast does your average rain drop...drop?
Post by: neilep on 22/03/2005 12:09:46
Hello, How are you today ?...I'm fine.

Good !!! that's the small talk over !!..what I simply must know today is how fast does the average rain drop drop ?.....I would guestimate between 5 and 10 mph ?....how do they measure this ? is it some kind of pressure mat on impact or do they measure it over distance fallen ?

I just want to know so that I can make my children think I'm clever[:D]

Thanks

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Title: Re: How fast does your average rain drop...drop !!
Post by: DrPhil on 23/03/2005 00:24:26
http://www.wonderquest.com/falling-raindrops.htm
http://ggweather.com/archive/weacornerdec02.htm
The terminal velocity of a falling raindrop through still air depends on its size. An average raindrop is about 2 millimeters in diameter and has a maximum fall rate of about 14.5 miles per hour or 21 feet per second. A large raindrop, 5 mm in diameter, falls at 20 mph (29 feet/second), but drops of this size tend to fall apart into smaller drops. Drizzle, which has a diameter of 0.5 mm, has a fall rate of 4.5 mph (7 feet/second).
Title: Re: How fast does your average rain drop...drop !!
Post by: neilep on 23/03/2005 08:30:55
Thank you Phil,

With such a preponderance of info on the web I might need never ask a question here again *sigh*......Thanks you for the excellent links....it's really appreciated.

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Title: Re: How fast does your average rain drop...drop !!
Post by: chris on 23/03/2005 08:40:45
Neil - this is something that Exodus has talked about in the past :

http://www.thenakedscientists.com/forum/topic.asp?TOPIC_ID=42&SearchTerms=raindrop

Chris

"I never forget a face, but in your case I'll make an exception"
- Groucho Marx
Title: Re: How fast does your average rain drop...drop !!
Post by: neilep on 23/03/2005 08:46:01
quote:
Originally posted by chris

Neil - this is something that Exodus has talked about in the past :

http://www.thenakedscientists.com/forum/topic.asp?TOPIC_ID=42&SearchTerms=raindrop

Chris

"I never forget a face, but in your case I'll make an exception"
- Groucho Marx

DOH !!...thanks Chris.

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Title: Re: How fast does your average rain drop...drop !!
Post by: chris on 23/03/2005 08:54:23
Neil - this is something that Exodus has talked about in the past :

http://www.thenakedscientists.com/forum/topic.asp?TOPIC_ID=42&SearchTerms=raindrop

Chris

"I never forget a face, but in your case I'll make an exception"
- Groucho Marx
Title: Re: How fast does your average rain drop...drop !!
Post by: BlazePascal on 22/06/2014 21:26:45
Not to be controversial, but I'm sitting on my back porch in Florida during a summer storm, and I've been trying to answer this question using my own methodology. This is a heavy storm (a "frog strangler," as we would say in these parts). The raindrops are falling through my field of vision, which I estimate to be 10 feet vertically, in a period of time I would estimate to be between a tenth and a fifth of a second. (As a percussionist and piano tuner, I'm pretty good at estimating small time quanta.) That yields speeds between 100 feet per second and 50 feet per second, or 66 MPH and 33 MPH, somewhat higher than the above solid numbers.