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Announcements Mar 28, 2026 at 8:42 AM

Have you ever noticed that breathing on your hand feels warm, but blowing on it feels cold? Why do you think that is?

Posted by Good_Car8569

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WonderfulGround9052 Mar 28, 2026 +2
yeah it's about the air speed and evaporation thing, when you breathe normally the air is slower and warmer from your lungs but when you blow hard it moves faster and makes moisture on your skin evaporate which cools you down same reason why fans work even though they don't actually lower temperature in the room
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[deleted] Mar 28, 2026 +1
[removed]
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Good_Car8569 Mar 28, 2026 +1
But when i blow slowly, its still cold..
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s-e-x_h-i-p-s Mar 28, 2026 +1
I blow slowly and it just gets harder. 
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Solvely_ Mar 28, 2026 +1
Well hold on now… are you like breathing into your hand with your mouth open?? Cuz that would explain lmao
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Salt-Marionberry-712 Mar 28, 2026 +1
Blowing decreases the 'borndry layer', which acts like insulsyion. Also, if humidity is less than 100%, evaporation of sweat on hands will do cooling. Breathing allows a thicker boundry layer, but also humidity in you breath can condense on cold hands. Also heat from inside your body.
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isthatwillythewanker Mar 28, 2026 +1
Some scientific tomfoolery or Benny bullshitery I suppose.
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Nervous_March8748 Mar 28, 2026 +1
It’s because your breath is warm, but blowing makes the air move faster and evaporates the moisture on your skin, which cools it down.
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Good_Car8569 Mar 28, 2026 +1
Make sense..
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prozack75 Mar 28, 2026 +1
It’s all to do with speed of the breath Faster the speed the quicker warm air (heated by your skin) is removed from above it and replaced by cooler air and so more heat with be lost due to the difference in temperature to the replaced air….the cooler you feel.
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velvetcrow5 Mar 28, 2026 +1
Your breath is host, it'll feel warm if you introduce it slowly. But if you blow quick air, that air distrupts the thin layer of warm air surrounding your hand. Suddenly your hand is losing heat much faster to environment, so it feels cold.
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Weary-Guidance-4514 Mar 28, 2026 +1
When you breathe slowly the air is fully heated by your lungs and comes out warm When you blow the air moves faster and accelerates evaporation on your skin which pulls heat away and makes it feel cold Same air completely different effect
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DilbertPark Mar 28, 2026 +1
It's the velocity of air from the mouth that reaches the hand that makes the difference. Higher velocity enhances convection heat loss on the skin surface that is why your hand feels cooler. Heat is convected away much faster when you blow onto it unlike when you simply breath out air into it.
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Unusual__League Mar 28, 2026 +1
The same reason why sun dries the wet cloth but causes you to sweat ..
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NoF0kxAllowedInside Mar 28, 2026 +1
“There is no place in my house for a man who can blow hot and cold with the same breath".
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