Sunday, December 23, 2012

Is it Better to Walk or Run in the Rain? (Updated)

Via It's Okay To Be Smart, a video on the logical and physical analysis of the advantages and disadvantages of various mid-precipitation avoidance strategies.



And here's Mythbusters proving the opposite:



UPDATED: As per an anonymous commenter, Mythbusters re-visited the question and came to the opposite conclusion:

REVISITED: You end up drier running in the rain than walking. 

CONFIRMED

When retrying the test in actual rain it was conclusively proven that the running test subject got less wet than the walking test subject. The use of artificial rain in the original test led to a false negative.

7 comments:

  1. Betcha the distribution of wetness will differ between the two cases. Walking minimizes frontal dampness, which seems a good idea in some circs, but running will be best for hairstyle preservation.

    Note that they didn't weigh the test subjects, so cranial moisture was ignored.

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  2. I believe I can remedy the two conclusions above. The pure thoery video does not take into account the amount that any particular article of clothing will absorb. The amount of each raindrop absorbed should depend on the force at which the raindrop strikes said given material. For example, let's say while walking (lower force) you absorb 80% of each raindrop but at higher velocity you absorb 85% of each raindrop. Then, even though you encountered the same amout of raindrops your total absorption of water would be greater in the running case. (Of course this deals with raindrops encountered horizontally, the force from above would be ~constant) I believe you would see different results with different clothing material.

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  3. Actually, Mythbusters re-tested and came to the conclusion that running is indeed better. See: http://mythbustersresults.com/episode38

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  4. Thanks for that - updated the post.

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  5. John has a point, but also, the amount of rain absorbed by many cloth items will depend on both the perpendicular speed of the drop, and the angle of incidence of the drop (which are interrelated, since the drops have a relatively constant downward speed, and therefore their angle of impact will be based on the horizontal speed. Move slow enough, and with the right material, the surface tension of the water will tend to make the droplets roll off your clothes.

    To truly minimize the amount of water, you should change the angle of your body as you run to equal the angle of incidence of the water. You'll get hit with the same amount of water, but it will all hit your hair, and your hair is really good at repelling water, especially once it is fully soaked.

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  6. It's very easy to see that the faster you go, the less wet you get. Imagine doing that same 50 feet, or whatever it is, in two hours. Can anyone imagine you wouldn't get wetter??

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