Question

Do you get wetter if you run or walk in the rain?

Asked by: Angela Dennis

Answer

A close friend of mine, and I actually performed a test on this. We put a cardboard sheet over our head and one in front of us. We walked over a 10ft space, it was a light drizzle so we would be able to count the number of drops that hit the sheets. The amount of rain drops that you will get hit by (in idle conditions, the area each person walks is equally dense as far as rain drops) is exactly the same whether you run or if you walk, as long as the time you are in the rain is the same.

The reason for the fact that you are hit by approximately the same amount, is because when you run, you are hit from above with less rain drops, however, with your forward velocity increasing, you hit more and more rain drops head on. As long as the time in the rain for both people is the same, you should get a close to equal number of rain drops. However, a person who sprints 100yds as opposed to a person who walks the 100yds will get hit by much less rain, because of the time it takes to travel the same distance.

So as a straight answer to your question, yes you will get hit with less rain drops if you run (bearing in mind there must be a significant difference in speed or difference (to change time) than if you walked.

Answered by: Cody



The empirical evidence presented notwithstanding, it seems implausible that the number of raindrops hitting a person per unit time remains constant whether running or walking. The answer posits that running will cause you to hit more raindrops on the front per second, with which I agree, but claims that you will be hit less often on the top, with which I disagree on the following grounds:

As a horizontal piece of cardboard moves forward, drops that would have hit it go behind it and thus miss. However one would expect an equal number of raindrops that would have fallen in front of the cardboard to now hit.

Therefore taking front and top into account, running should cause you to intersect more drops per second than walking, but will take less time to cover a certain distance. How these 2 effects balance out remains to be seen.

Mathematical models which assume raindrops falling vertically in planes with randomly distributed drops within the plane show the two effects to balance out perfectly, but the real life application? Who knows...

Answered by: Robert Landolfi

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