<p>why does it feel colder to stick out a water covered hand on a cold winter day than a dry hand?</p>
<p>Is it because the water increase the thermal conductivity of the hand or is it because the water evaporate and takes away heat from the hand? Can water evaporate even in freezing temp?</p>
<p>Thanks</p>
<p>um why is this in the MIT section? oh well</p>
<p>like you said, it’s colder because water is evaporating and taking heat from hand.
and there is water vapor even at freezing temperature, just less of it when compared to hotter weather. thats how you get humidity!</p>
<p>i hope this helps and that i am not wrong >.<</p>
<p>Think of it this way: how does sweat work?</p>
<p>its because of the evaporation of the water.
there is air dissolved in liquids such as water. occasionally, a particularly energetic air molecule will escape from the liquid. however, the reverse process occurs too. sometimes an air molecule (not originally dissolved in the liquid) will enter the liquid. usually there is a balance (which depends on air pressure i think) so that the situation appears static as a whole.</p>
<p>when you have wind blowing then essentially your cutting off one part of the process. you no longer have as many particles that enter the liquid, but you still have air particles leaving the liquid. the particles leaving the liquid are more energetic, and thus when they leave, the temperature of the water tends to drop. thus blowing air at a liquid cools the liquid.</p>
<p>of course this is a simplified view of the situation, but it is partially correct.</p>