What would feel hotter?

[fleabag]

What would feel hotter, taking an 98F shower/submerged in a body of water that is 98F or be in an area where the air temperature is 98F? Maybe 50% humidity and 100% humidity?

 

[bigal40]

the 100% humidity and the water would feel the same because in both cases your body won't be cooled by your sweat evaporating. the 50% humidity would feel the coolest

 

[Cogman]

Originally posted by: bigal40
the 100% humidity and the water would feel the same because in both cases your body won't be cooled by your sweat evaporating. the 50% humidity would feel the coolest

I disagree. The shower would feel the coolest. lots of cascading water evaporating off the body = cool feeling. Not only that, but (depending on the size of the water), being submerged in 98C water would probably leave you feeling cooler then just walking around in 98* temperature. That's because the heat produced by your body will be quickly removed and dispersed while in the water, however, when you are in open air the heat will tend to collect around you (making a temperature that is above 98F. Even if you have no close on, you will be able to feels some of the heat generated by your body when you are in the open air.

100% humidity (no rain) would leave you feeling the hottest as your sweat would evaporate less while the heat isn't able to disperse into the environment.

 

[Biftheunderstudy]

The property that makes you feel hot or cold is dependent on the heat transfer rate. This rate depends on a few things:
1) The thickness -- can't change this really, I guess you could put on more clothes but lets say naked.
2) The thermal conductivity of the medium -- water has a higher k value so would increase the heat transfer rate over air @ 50% humidity
3) Surface area -- again can't really change this
4) Temperature Difference -- since the body has an average temperature of 98.6 then deltat is -0.6 -- the body is losing heat to the environment

Now this is not the whole picture, we haven't included fluid flow to this model. If you are standing in non-moving air vs shower vs bath then it will go like this in order of heat transfer rate:
Shower -> bath -> 100% humidity -> 50% humidity
But I neglected physiological effects that bigal40 mentioned, your body sweats so that it can evaporate and lose heat in the form of latent heat of vaporization when the sweat evaporates but this is harder to do in a 100% humidity. But this is only when the ambient temperature is higher than the body temperature. If it were 100 degrees then:
Edit: 50%->100%->bath->shower

So the shower feels coldest, followed by the bath then air with higher humidity first.

Bath and 100% humidity are not the same because of the different thermal conductivities, 100% humidity is a concentration of water vapor and is not the same as liquid water.

This means the shower will feel the coldest because the transfer rate is the highest

 

[silverpig]

Originally posted by: Biftheunderstudy
The property that makes you feel hot or cold is dependent on the heat transfer rate. This rate depends on a few things:
1) The thickness -- can't change this really, I guess you could put on more clothes but lets say naked.
2) The thermal conductivity of the medium -- water has a higher k value so would increase the heat transfer rate over air @ 50% humidity
3) Surface area -- again can't really change this
4) Temperature Difference -- since the body has an average temperature of 98.6 then deltat is -0.6 -- the body is losing heat to the environment

Now this is not the whole picture, we haven't included fluid flow to this model. If you are standing in non-moving air vs shower vs bath then it will go like this in order of heat transfer rate:
Shower -> bath -> 100% humidity -> 50% humidity
But I neglected physiological effects that bigal40 mentioned, your body sweats so that it can evaporate and lose heat in the form of latent heat of vaporization when the sweat evaporates but this is harder to do in a 100% humidity. But this is only when the ambient temperature is higher than the body temperature. If it were 100 degrees then:
Edit: 50%->100%->bath->shower

So the shower feels coldest, followed by the bath then air with higher humidity first.

Bath and 100% humidity are not the same because of the different thermal conductivities, 100% humidity is a concentration of water vapor and is not the same as liquid water.

This means the shower will feel the coldest because the transfer rate is the highest

But all are at body temperature... (allow for the .6F difference to be the OP's lack of precision).

 

[Cogman]

Originally posted by: silverpig

Originally posted by: Biftheunderstudy
The property that makes you feel hot or cold is dependent on the heat transfer rate. This rate depends on a few things:
1) The thickness -- can't change this really, I guess you could put on more clothes but lets say naked.
2) The thermal conductivity of the medium -- water has a higher k value so would increase the heat transfer rate over air @ 50% humidity
3) Surface area -- again can't really change this
4) Temperature Difference -- since the body has an average temperature of 98.6 then deltat is -0.6 -- the body is losing heat to the environment

Now this is not the whole picture, we haven't included fluid flow to this model. If you are standing in non-moving air vs shower vs bath then it will go like this in order of heat transfer rate:
Shower -> bath -> 100% humidity -> 50% humidity
But I neglected physiological effects that bigal40 mentioned, your body sweats so that it can evaporate and lose heat in the form of latent heat of vaporization when the sweat evaporates but this is harder to do in a 100% humidity. But this is only when the ambient temperature is higher than the body temperature. If it were 100 degrees then:
Edit: 50%->100%->bath->shower

So the shower feels coldest, followed by the bath then air with higher humidity first.

Bath and 100% humidity are not the same because of the different thermal conductivities, 100% humidity is a concentration of water vapor and is not the same as liquid water.

This means the shower will feel the coldest because the transfer rate is the highest

But all are at body temperature... (allow for the .6F difference to be the OP's lack of precision).

Your body still generates heat, even when it it is at its correct body temperature. It may pull some tricks like slowing down its metabolism, but it still generates heat.

Water will pull that generated heat away a lot easier then the open air will, hence the reason that 98* water will feel cooler.

 

[KIAman]

Originally posted by: Cogman

Originally posted by: silverpig

Originally posted by: Biftheunderstudy
The property that makes you feel hot or cold is dependent on the heat transfer rate. This rate depends on a few things:
1) The thickness -- can't change this really, I guess you could put on more clothes but lets say naked.
2) The thermal conductivity of the medium -- water has a higher k value so would increase the heat transfer rate over air @ 50% humidity
3) Surface area -- again can't really change this
4) Temperature Difference -- since the body has an average temperature of 98.6 then deltat is -0.6 -- the body is losing heat to the environment

Now this is not the whole picture, we haven't included fluid flow to this model. If you are standing in non-moving air vs shower vs bath then it will go like this in order of heat transfer rate:
Shower -> bath -> 100% humidity -> 50% humidity
But I neglected physiological effects that bigal40 mentioned, your body sweats so that it can evaporate and lose heat in the form of latent heat of vaporization when the sweat evaporates but this is harder to do in a 100% humidity. But this is only when the ambient temperature is higher than the body temperature. If it were 100 degrees then:
Edit: 50%->100%->bath->shower

So the shower feels coldest, followed by the bath then air with higher humidity first.

Bath and 100% humidity are not the same because of the different thermal conductivities, 100% humidity is a concentration of water vapor and is not the same as liquid water.

This means the shower will feel the coldest because the transfer rate is the highest

But all are at body temperature... (allow for the .6F difference to be the OP's lack of precision).

Your body still generates heat, even when it it is at its correct body temperature. It may pull some tricks like slowing down its metabolism, but it still generates heat.

Water will pull that generated heat away a lot easier then the open air will, hence the reason that 98* water will feel cooler.

Skin temperature is average 90F. Anything more than that will "feel" hotter as according to the 2nd Law of Thermodynamics, when heat is transferred from one body to another, the temperatures equalize. The sensation of heat on the skin is determined by the speed of temperature transfer.

Water transfers heat better than air. The 98F water will feel hotter, followed by shower, followed by 100% humidity air, followed by 50% humidity air.

 

[soccerballtux]

Originally posted by: bigal40
the 100% humidity and the water would feel the same because in both cases your body won't be cooled by your sweat evaporating. the 50% humidity would feel the coolest

Ooo edit. 98 degrees shower will feel coolest-- still 0.6 degrees below human body temp.

 

[silverpig]

Why doesn't someone just do the damn test?

 

[Pulsar]

This question is far too poorly specified to be answered.

For instance, in the shower, what is the air temperature and humidty? Are we to assume 100% immersion of the body?

 

[fleabag]

Originally posted by: Pulsar
This question is far too poorly specified to be answered.

For instance, in the shower, what is the air temperature and humidty? Are we to assume 100% immersion of the body?

Yes 100% immersion of the body, shower or bath tub, jacuzzi at 98F what ever, point being, why would it appear that 100% humidity 98F be hotter than 50% or 20% humidity 98F or being submerged in 98F water?

Just remember, everything is at 98F, air, water, what ever..

 

[NewTweeker]

98F shower isn't very hot. normal shower is about 110, and that feels nice, but over, say an hour exposure could scald or cause your body core temperature to raise dangerously. 98F is a sweet spot. After an hour the water would still seem mild. Odds are you aren't doing anything too aerobic in the shower that would cause your body to need to get rid of extra heat. Or are you? Even if you are, the water pouring over your body will keep you comfortable. Following that 100% humidity is rain, so it's the same as a shower, as long as you strip off the cloths that would be holding in any heat. 50% and 20% humidity are keeping your sweat from evaporating, and your body can't dissipate heat when it does work (or just respirates) . No such problems exist in a shower or in rain, so they would feel comfortable.


See ya around

 

[WildHorse]

Originally posted by: NewTweeker

See ya around

O.K., see ya around


And remember...don't let anybody slap you with a wet fish