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Will running during rainfall makes you more wet?

  1. Oct 21, 2011 #1
    (sorry for the typo in the title)

    I have heard both yes and no when it comes to this. But now it's time to ask you guys who probably really can put this to test.

    Certain factors is probably like the angle of the falling rain relative to your motion, right? And the volume per cubic meter of rain? The speed of the person walking/running? The speed of the falling rain (or is the velocity v always the same for rain?)? The density of the water droplets?

    I think you understand, what's the truth?

    Thanks in advance!
     
  2. jcsd
  3. Oct 21, 2011 #2
    I depends how far the shelter is and how long the rainstorm lasts. If also depends on your defintion of "wet". If your head is wet, it usually means more to you than when your body is wet. However, running will always make you wetter faster, if you are not getting to shelter before the rainstorm is finished.
     
  4. Oct 21, 2011 #3
    Well, you will get wet as you will run into raindrops falling in front of you (already past the height of the top of your head), but then you will avoid raindrops about to fall on top of you (on your head).
    Regardless of if you run or walk you should walk/run into roughly the same amount of raindrops, but if you run you should get fewer raindrops on your head.
    In conclusion, running will keep you (your head) drier.

    In answer to one of your sub-questions: raindrops will tend to fall at a similar speed (their terminal velocity), this does depend, though, on their size, but the outcome will be the same for every type of rain; running = drier head.

    If the rain is angled considerably in the same direction as you are headed then running will definitely keep you much drier than walking as you'll be moving with it (less difference between your horizontal vectors, ergo fewer collisions).

    Lastly, I think raindrops' density tends to stay the same (that of normal water).

    All this is assuming the rate of rainfall remains constant and ceteris paribus etc. etc. throughout the rainy passage.

    Hope it helped!
     
  5. Oct 21, 2011 #4
    That might work if you are a sphere. but you are not.
     
  6. Oct 21, 2011 #5
    Care to elaborate?
     
  7. Oct 21, 2011 #6

    A.T.

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    A nice way to visualize this is the reference frame of the falling raindrops: The drops are a static field, and the person is moving though them and collecting them, until he reaches a boundary. The horizontal boundary is the begin of a shelter. The vertical boundary is the end of the rain shower. The optimal behavior depends on how far away he is from each boundary, and the geometry that you assume for the body.

    If the rain is going to last to infinity, you should obviously run.
     
  8. Oct 21, 2011 #7
    I think Mythbusters did a show on this.
     
  9. Oct 21, 2011 #8
    I was just about to say that. They did. They put "spongy" suits on and ran through different rates of rain. Running does make you more wet if its raining really hard because you allow for a lot more surface area since youre hitting the rain with the whole front of your body. If you walk, mostly the shoulders get saturated.
     
  10. Oct 21, 2011 #9
  11. Oct 21, 2011 #10

    marcusl

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    Here's a thread that dealt extensively with your question
    https://www.physicsforums.com/showthread.php?t=204749"
    If rain is falling straight down, your speed changes the distribution of wetness but not how wet you get. Unless you run so fast that you bend forward, in which case you sweep out less volume and get less wet.
     
    Last edited by a moderator: Apr 26, 2017
  12. Oct 21, 2011 #11
    Thanks for the replies guys. From reading the other post in this forum I get the impression of it doesn't really matter? Some people are truly convinced arguing that you will get more wet if you run, some the opposite.

    And according to the discussed formula in the beginning of the post it looked like you will get less wet if you run.

    If rain were falling in angle towards your relative motion it seems to makes you more wet, which I also find obvious.

    But the question is, rain falling straight down? More wet by running, yes or no? I've gotten more confused now :D
     
  13. Oct 21, 2011 #12
    Even if you have certain horizontal velocity the rain will appear as if falling through an angle. this is because you tend to move towards the raindrops just in front of you.
     
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