Why you feel cold going in and coming out of a pool/sea/ocean

[Terzo]

I'm sure you've noticed the same. You're at the beach, and run into the ocean and it is freezing. With a little bit of time, you adjust and the water is comfortable. However, when you're ready to go back onto the beach, the air itself feels cold. Why is this?

I can understand the first part. The air temperature is likely much warmer than the water, so the water feeling cold makes sense. But why the same when you leave the water?

My only guess (and I don't think it's right) is that since water is a better conductor of heat, your body temperature has dropped somewhat when you leave the water. Thus, you feel cold until the air warms you up again. But even then, I'd figure the air would feel warmer, even if your body temperature is slightly lower than normal.

And yes, I could easily find the answer with google, but I'd rather see what you guys think.

 

[CRXican]

evaporation

 

[crownjules]

Look up evaporational cooling. It's the same process that our body replicates naturally through sweating.

 

[OCGuy]

Same way that sweating water that is warmer than the air around you can cool you down?

 

[Homerboy]

wow

 

[CRXican]

wow

dude it's science

 

[xanis]

dude it's science

 

[slayer202]

evaporation

thread solved in under 2 minutes

 

[Terzo]

Look up evaporational cooling. It's the same process that our body replicates naturally through sweating.

Thanks. I'm looking it up but I'm not entirely following. Are you saying that when you get out of the water, you're wet, and that whisks heat away from you until the water evaporates?

 

[Regs]

Water has high thermal inertia compared to air. So when water is introduced to cold air, it holds the temperature of the air(atmosphere) and makes your body work twice as hard to maintain normal body temperature (98.6f).

You have to think of it like this: Your body is always fighting to keep 98.6f. At 75 degrees in normal atmosphere air your body does not have to work as hard to maintain temperature of the surrounding air. But when water at 75 degrees is introduced into the equation, your body now has to compete with all atmospheric variables, which includes the cold water that takes longer to heat up than air.

 

[Iron Woode]

And yes, I could easily find the answer with google, but I'd rather see what you guys think.

big mistake!

they are going to rip you a new one.

 

[MotF Bane]

:facepalm:

 

[Terzo]

Water has high thermal inertia compared to air. So when water is introduced to cold air, it holds the tempature of the air(atmosphere) and makes your body work twice as hard to maintain normal body tempature (98.6f).

I'm assuming thermal inertia is similar to "regular" inertia, in that higher thermal intertia means it's harder to change the temperature?

big mistake!

they are going to rip you a new one.

Heh, first thing I learned from this thread!

 

[sao123]

when you get in the water, its cold because the water is cooler than the air...

when you get out of the water, its cold because its later and the air has cooled off.

 

[Regs]

I'm assuming thermal inertia is similar to "regular" inertia, in that higher thermal intertia means it's harder to change the temperature?



Heh, first thing I learned from this thread!

Correct. The thermal properties of water do not equal that of air. Which is why people freeze to death or suffer from hypothermia in cold water.

Humidity is one other such variable that can be added to this equation. When the humidity is high, your bodies dead skin sticks to your body making it harder for your skin to vent off heat.

 

[911paramedic]

I'm typing this with my brain because both my hands are on my face. :doublefacepalm:

 

[Terzo]

Correct. The thermal properties of water do not equal that of air. Which is why people freeze to death or suffer from hypothermia in cold water.

Humidity is one other such variable that can be added to this equation. When the humidity is high, your bodies dead skin sticks to your body making it harder for your skin to vent off heat.

:thumbsup:
Thanks for the explanations, even if you had to facepalm first.

 

[DrPizza]

Hmmm....

Actually, if you jump into water that's cold enough on a warm enough day, when you get out of the water, it'll still feel warmer. (I think.) I believe it's related to the dew point. (Which is related to evaporative cooling with the humidity factored in.) Thus, if it's 70 degrees outside, and you jump into 32 degree water, when you get out of the water, it'll feel like it's 40 or 50.

 

[Kommander_Kink]

I also notice then when you are working outside in the cold and go inside to eat lunch, it feels way colder after you have eaten a snack and go back to work.

 

[SP33Demon]

Have you gone to middle school yet?

 

[geno]

Thanks. I'm looking it up but I'm not entirely following. Are you saying that when you get out of the water, you're wet, and that whisks heat away from you until the water evaporates?

evaporation = hot water leaves, cold stays.

 

[GoSharks]

When the humidity is high, your bodies dead skin sticks to your body making it harder for your skin to vent off heat. [/FONT][/COLOR]

:facepalm:

 

[JTsyo]

I also notice then when you are working outside in the cold and go inside to eat lunch, it feels way colder after you have eaten a snack and go back to work.

When you eat, blood is used more by the digestive system. This might mean there's less circulation at your limbs for heating. that's my guess at it.

Thermal "inertia" = Specific heat
I wondered if there was actual thermal inertia. For example say you had an object at 100F and another at 120F. You want to cool both to 75F. If you start cooling the 120F first and then start the 100F one when the first reaches the same temp, will both reach 75F at the same time? This assumes that there's no gradient through the body.

 

[Regs]

:facepalm:

Dead skin and humidity limits evaporation which makes cooling of the blood more difficult.

What was so hard to extrapolate from that?

 

[Modular]

big mistake!

they are going to rip you a new one.

Mission in progress sir!