

Do you get less wet if you run in the rain? - vinutheraj
http://news.bbc.co.uk/1/hi/magazine/4562132.stm

======
vinutheraj
Conclusion: To get to a specific place you get more wet by walking. To travel
for a specific period of time you get more wet by running.

~~~
xiaoma
I've been running on and off for the past 16 years. In my experience, I do
_not_ get as wet while running in the rain as I would just standing in it.

I think there must be a missing variable, such as excess water whisking off
more quickly, greater evaporation due to heat transfer or maybe something
else.

~~~
iigs
Perhaps a more forward posture causes the front of your body to be "shaded" by
the rest of your body, leaving the front (that you notice more) drier?

------
mronge
I've spent a lot of time learning math (have a CS degree, which required lots
of math). But sadly, I'm not comfortable enough with differential equations to
come up with a solution like the first part. It makes sense once someone else
has done it, but I wouldn't have gotten that far.

Perhaps I just need more practice. Practice makes perfect with math like
everything else?

~~~
lliiffee
You don't really need much math to understand this. Imagine that a person is a
perfect cube. The amount of rain hitting the _top_ of this cube is constant--
does not depend on the speed of the cube. The amount of rain hitting the
_front_ of the cube is proportional to how fast the cube is moving. From this
insight, everything else is algebra.

~~~
mronge
I was referring to coming with the differential equation first presented.

Understanding it is one thing, but coming up with it independently is
different.

~~~
mdakin
I wonder if the multivariate nature of this problem is throwing you off more
than the differential equation aspect of it. If you know multivariable
calculus you can think about this problem at a higher level of abstraction
(vector fields and flux). The integral you see is the output of the thinking
at that higher level of abstraction.

I bet with proper background and practice you could set things like this up
rather easily. You just need to learn to think about the problems at the
proper abstraction level and then develop some intuition by actually doing
lots of problems.

------
yan
What contributes to how I feel when I arrive isn't the factor of my wetness,
but how long I spent being rained on.

~~~
req2
<http://en.wikipedia.org/wiki/Peak-end_rule> begs to differ.

~~~
yan
It can beg all it wants, I'm still gonna run :)

I stop thinking about being in the rain as soon as I'm sheltered, so I'd
rather minimize being in an unpleasant situation.

------
ekanes
Nice. A fun/rational way to look at what is at heart an emotional decision. :)

Another angle on this is that running spreads the wetness over more surface
area (less on top, more on front). If you're wearing a hat, you might choose
to walk, etc.

------
run4yourlives
I won't argue the conclusion, just introduce an anecdotal observation.

When it is spitting or raining very lightly, sit in a stopped car and watch
the rain on the window.

Now, speed that car up to about 80km and see what happens. Disregarding spray
from other vehicles, odds are that there will be _more_ rain on the windshield
in the same amount of time.

Like I said just an observation.

~~~
RiderOfGiraffes
Yes, but for a given distance you get less rain on the windscreen when you
drive fast, rather than driving slowly.

~~~
run4yourlives
Of course, because you've substantially reduced your exposure time. But the
act of increasing your speed itself actually causes you to come in contact
with _more_ raindrops, not less.

~~~
RiderOfGiraffes
Per unit time, yes. Per unit distance, no.

I'm just not getting you. I'm giving up.

------
yummyfajitas
I once asked this question on a calculus exam.

~~~
wvl
This question is the reason I went into engineering.

I learned calculus by correspondence in high school. Solving this problem
transformed calculus in my mind from just some abstract problems to solve into
something useful. It was a big turning point for me, and focused my interests
in areas of applied math.

------
bradlane
didn't the mythbusters test this in one of their first couple of seasons?
iirc, they did, and came to the same conclusion

~~~
thorax
They originally said if you ran you got more wet:
[http://en.wikipedia.org/wiki/MythBusters_%28season_1%29#Who_...](http://en.wikipedia.org/wiki/MythBusters_%28season_1%29#Who_Gets_Wetter.3F)

But then they changed their mind after that show:
[http://en.wikipedia.org/wiki/MythBusters_episodes:_Season_3#...](http://en.wikipedia.org/wiki/MythBusters_episodes:_Season_3#Who_Gets_Wetter.3F)

------
tlrobinson
I used to ride my bike to class in the rain, and I would always get more wet
than if I walked.

~~~
swolchok
It's possible for this to be true, since on a bicycle you may tend to expose
both your back and front to the rain more so than when walking.

~~~
jaydub
Also, chances are that you kick up water as well

