On September 08 2016 07:43 OtherWorld wrote: What is the most efficient position to fall asleep in when it's really hot in your room, physics-wise?
Not trying to be comprehensive, but an important factor is to have your arms spread open or even over your head, so that your armpits are exposed. The blood vessels are very superficial there, and it is also where we usually start to sweat, so by having them as exposed as possible you maximise that cooling mechanism.
On September 08 2016 08:59 Epishade wrote: What if the air surrounding you is hotter than body temperature? Would you want to expose less of yourself then?
The body cools itself by evaporating sweat, and you expose yourself to facilitate that process, so no.
I suppose if the air is hotter than body temperature, and the humidity is at 100%, and there's no wind for convection, then there isn't any benefit to exposing more surface area. I doubt covering yourself would help though. You probably just die of a heat stroke.
On September 08 2016 08:59 Epishade wrote: What if the air surrounding you is hotter than body temperature? Would you want to expose less of yourself then?
The body cools itself by evaporating sweat, and you expose yourself to facilitate that process, so no.
I suppose if the air is hotter than body temperature, and the humidity is at 100%, and there's no wind for convection, then there isn't any benefit to exposing more surface area. I doubt covering yourself would help though. You probably just die of a heat stroke.
I agree on the sweating part, but maybe there is something to it... I mean... If your skin is at 33 degrees, and the air is 40, then you cool down the air around you. Is there a way to recycle that cooled air without interfering too much with the sweat evaporating? What if you're not sweating that much?
On September 08 2016 08:59 Epishade wrote: What if the air surrounding you is hotter than body temperature? Would you want to expose less of yourself then?
The body cools itself by evaporating sweat, and you expose yourself to facilitate that process, so no.
I suppose if the air is hotter than body temperature, and the humidity is at 100%, and there's no wind for convection, then there isn't any benefit to exposing more surface area. I doubt covering yourself would help though. You probably just die of a heat stroke.
I agree on the sweating part, but maybe there is something to it... I mean... If your skin is at 33 degrees, and the air is 40, then you cool down the air around you. Is there a way to recycle that cooled air without interfering too much with the sweat evaporating? What if you're not sweating that much?
There isn't any cool air though. The surrounding air is transferring heat to you, and you're getting rid of it by using the body's heat to create water vapor. Even if you cut yourself off from the surrounding air, you'd still heat up due to your body's internal processes, since sweating won't help without unsaturated air. Covering up does help when there's a third source of energy (radiated from the sun), so there might be something smart you could do with convection I suppose.
On September 08 2016 08:59 Epishade wrote: What if the air surrounding you is hotter than body temperature? Would you want to expose less of yourself then?
The body cools itself by evaporating sweat, and you expose yourself to facilitate that process, so no.
I suppose if the air is hotter than body temperature, and the humidity is at 100%, and there's no wind for convection, then there isn't any benefit to exposing more surface area. I doubt covering yourself would help though. You probably just die of a heat stroke.
I agree on the sweating part, but maybe there is something to it... I mean... If your skin is at 33 degrees, and the air is 40, then you cool down the air around you. Is there a way to recycle that cooled air without interfering too much with the sweat evaporating? What if you're not sweating that much?
There isn't any cool air though. The surrounding air is transferring heat to you, and you're getting rid of it by using the body's heat to create water vapor. Even if you cut yourself off from the surrounding air, you'd still heat up due to your body's internal processes, since sweating won't help without unsaturated air. Covering up does help when there's a third source of energy (radiated from the sun), so there might be something smart you could do with convection I suppose.
If the surrounding air is transferring heat, surely the air must drop in temperature? I'm not talking about the evaporation cooling, but just usual heat transfer from the hotter air to the colder skin. If fully exposed, the chilled air will fall down and away (as it is heavier), but maybe there is a way to trap some of the cold air to reduce body heating. You wouldn't completely cover yourself up, for the reasons you give, but maybe you can do something smart anyway... I'm thinking of these open-top freezers that keep most of the cold because the cold air stays in the freezer. What if you do something similar? Build some walls around yourself to trap the cold air, while still allowing the steam to diffuse out in the room?
On September 08 2016 08:59 Epishade wrote: What if the air surrounding you is hotter than body temperature? Would you want to expose less of yourself then?
The body cools itself by evaporating sweat, and you expose yourself to facilitate that process, so no.
I suppose if the air is hotter than body temperature, and the humidity is at 100%, and there's no wind for convection, then there isn't any benefit to exposing more surface area. I doubt covering yourself would help though. You probably just die of a heat stroke.
I agree on the sweating part, but maybe there is something to it... I mean... If your skin is at 33 degrees, and the air is 40, then you cool down the air around you. Is there a way to recycle that cooled air without interfering too much with the sweat evaporating? What if you're not sweating that much?
There isn't any cool air though. The surrounding air is transferring heat to you, and you're getting rid of it by using the body's heat to create water vapor. Even if you cut yourself off from the surrounding air, you'd still heat up due to your body's internal processes, since sweating won't help without unsaturated air. Covering up does help when there's a third source of energy (radiated from the sun), so there might be something smart you could do with convection I suppose.
If the surrounding air is transferring heat, surely the air must drop in temperature? I'm not talking about the evaporation cooling, but just usual heat transfer from the hotter air to the colder skin. If fully exposed, the chilled air will fall down and away (as it is heavier), but maybe there is a way to trap some of the cold air to reduce body heating. You wouldn't completely cover yourself up, for the reasons you give, but maybe you can do something smart anyway... I'm thinking of these open-top freezers that keep most of the cold because the cold air stays in the freezer. What if you do something similar? Build some walls around yourself to trap the cold air, while still allowing the steam to diffuse out in the room?
The surrounding air is transferring heat to the body and is thus colder than the rest of the air, but it's still warmer than the body. I don't think it's possible to trap the relatively cooler air near your body while allowing water vapor through (barring bizarre solutions exploiting the fact that the water vapor is polar covalent while the air should be non-polar... Wait, does that work?). An open-top freezer solution works of course, but that's just a basement, not anything you can do with clothes or covers.
On September 08 2016 08:59 Epishade wrote: What if the air surrounding you is hotter than body temperature? Would you want to expose less of yourself then?
The body cools itself by evaporating sweat, and you expose yourself to facilitate that process, so no.
I suppose if the air is hotter than body temperature, and the humidity is at 100%, and there's no wind for convection, then there isn't any benefit to exposing more surface area. I doubt covering yourself would help though. You probably just die of a heat stroke.
I agree on the sweating part, but maybe there is something to it... I mean... If your skin is at 33 degrees, and the air is 40, then you cool down the air around you. Is there a way to recycle that cooled air without interfering too much with the sweat evaporating? What if you're not sweating that much?
There isn't any cool air though. The surrounding air is transferring heat to you, and you're getting rid of it by using the body's heat to create water vapor. Even if you cut yourself off from the surrounding air, you'd still heat up due to your body's internal processes, since sweating won't help without unsaturated air. Covering up does help when there's a third source of energy (radiated from the sun), so there might be something smart you could do with convection I suppose.
If the surrounding air is transferring heat, surely the air must drop in temperature? I'm not talking about the evaporation cooling, but just usual heat transfer from the hotter air to the colder skin. If fully exposed, the chilled air will fall down and away (as it is heavier), but maybe there is a way to trap some of the cold air to reduce body heating. You wouldn't completely cover yourself up, for the reasons you give, but maybe you can do something smart anyway... I'm thinking of these open-top freezers that keep most of the cold because the cold air stays in the freezer. What if you do something similar? Build some walls around yourself to trap the cold air, while still allowing the steam to diffuse out in the room?
The surrounding air is transferring heat to the body and is thus colder than the rest of the air, but it's still warmer than the body. I don't think it's possible to trap the relatively cooler air near your body while allowing water vapor through (barring bizarre solutions exploiting the fact that the water vapor is polar covalent while the air should be non-polar... Wait, does that work?). An open-top freezer solution works of course, but that's just a basement, not anything you can do with clothes or covers.
What if you put the cover in a little wall around you in the bed?
What are all of the specific adaptations that would allow a Speedster (aka someone with Super Speed) to go at the speeds they go (lets assume the speed of sound, for simplicity) without the general physical issues caused by going at these speeds.
For example, one of the most common issues is the issue of friction burning your clothing off.
On September 08 2016 08:59 Epishade wrote: What if the air surrounding you is hotter than body temperature? Would you want to expose less of yourself then?
The body cools itself by evaporating sweat, and you expose yourself to facilitate that process, so no.
I suppose if the air is hotter than body temperature, and the humidity is at 100%, and there's no wind for convection, then there isn't any benefit to exposing more surface area. I doubt covering yourself would help though. You probably just die of a heat stroke.
I agree on the sweating part, but maybe there is something to it... I mean... If your skin is at 33 degrees, and the air is 40, then you cool down the air around you. Is there a way to recycle that cooled air without interfering too much with the sweat evaporating? What if you're not sweating that much?
There isn't any cool air though. The surrounding air is transferring heat to you, and you're getting rid of it by using the body's heat to create water vapor. Even if you cut yourself off from the surrounding air, you'd still heat up due to your body's internal processes, since sweating won't help without unsaturated air. Covering up does help when there's a third source of energy (radiated from the sun), so there might be something smart you could do with convection I suppose.
If the surrounding air is transferring heat, surely the air must drop in temperature? I'm not talking about the evaporation cooling, but just usual heat transfer from the hotter air to the colder skin. If fully exposed, the chilled air will fall down and away (as it is heavier), but maybe there is a way to trap some of the cold air to reduce body heating. You wouldn't completely cover yourself up, for the reasons you give, but maybe you can do something smart anyway... I'm thinking of these open-top freezers that keep most of the cold because the cold air stays in the freezer. What if you do something similar? Build some walls around yourself to trap the cold air, while still allowing the steam to diffuse out in the room?
The surrounding air is transferring heat to the body and is thus colder than the rest of the air, but it's still warmer than the body. I don't think it's possible to trap the relatively cooler air near your body while allowing water vapor through (barring bizarre solutions exploiting the fact that the water vapor is polar covalent while the air should be non-polar... Wait, does that work?). An open-top freezer solution works of course, but that's just a basement, not anything you can do with clothes or covers.
What if you put the cover in a little wall around you in the bed?
That you certainly could.
On September 08 2016 13:32 Zambrah wrote: What are all of the specific adaptations that would allow a Speedster (aka someone with Super Speed) to go at the speeds they go (lets assume the speed of sound, for simplicity) without the general physical issues caused by going at these speeds.
For example, one of the most common issues is the issue of friction burning your clothing off.
What does your skin need to be like? Your organs?
What are the mental effects?
Inquiring minds want to know.
Friction wouldn't burn off clothes when going at (only) Mach 1. Guys like John Stapp () have done tests and the human body seems to stand up to those speeds just fine (okay, they never went up to mach 1, but he flew a plane at 0.75 mach with no canopy and was okay).
The only real problem is actually running at those speeds without your muscles overheating, and your legs shattering due to running that fast. Speedsters generally go much faster than mach 1 though, and bring up problems that have more to do with relativistic physics than biology.
On September 08 2016 08:59 Epishade wrote: What if the air surrounding you is hotter than body temperature? Would you want to expose less of yourself then?
The body cools itself by evaporating sweat, and you expose yourself to facilitate that process, so no.
I suppose if the air is hotter than body temperature, and the humidity is at 100%, and there's no wind for convection, then there isn't any benefit to exposing more surface area. I doubt covering yourself would help though. You probably just die of a heat stroke.
I agree on the sweating part, but maybe there is something to it... I mean... If your skin is at 33 degrees, and the air is 40, then you cool down the air around you. Is there a way to recycle that cooled air without interfering too much with the sweat evaporating? What if you're not sweating that much?
There isn't any cool air though. The surrounding air is transferring heat to you, and you're getting rid of it by using the body's heat to create water vapor. Even if you cut yourself off from the surrounding air, you'd still heat up due to your body's internal processes, since sweating won't help without unsaturated air. Covering up does help when there's a third source of energy (radiated from the sun), so there might be something smart you could do with convection I suppose.
If the surrounding air is transferring heat, surely the air must drop in temperature? I'm not talking about the evaporation cooling, but just usual heat transfer from the hotter air to the colder skin. If fully exposed, the chilled air will fall down and away (as it is heavier), but maybe there is a way to trap some of the cold air to reduce body heating. You wouldn't completely cover yourself up, for the reasons you give, but maybe you can do something smart anyway... I'm thinking of these open-top freezers that keep most of the cold because the cold air stays in the freezer. What if you do something similar? Build some walls around yourself to trap the cold air, while still allowing the steam to diffuse out in the room?
The surrounding air is transferring heat to the body and is thus colder than the rest of the air, but it's still warmer than the body. I don't think it's possible to trap the relatively cooler air near your body while allowing water vapor through (barring bizarre solutions exploiting the fact that the water vapor is polar covalent while the air should be non-polar... Wait, does that work?). An open-top freezer solution works of course, but that's just a basement, not anything you can do with clothes or covers.
What if you put the cover in a little wall around you in the bed?
On September 08 2016 13:32 Zambrah wrote: What are all of the specific adaptations that would allow a Speedster (aka someone with Super Speed) to go at the speeds they go (lets assume the speed of sound, for simplicity) without the general physical issues caused by going at these speeds.
For example, one of the most common issues is the issue of friction burning your clothing off.
What does your skin need to be like? Your organs?
What are the mental effects?
Inquiring minds want to know.
Friction wouldn't burn off clothes when going at (only) Mach 1. Guys like John Stapp (https://www.youtube.com/watch?v=LfBvXC9MQj8) have done tests and the human body seems to stand up to those speeds just fine (okay, they never went up to mach 1, but he flew a plane at 0.75 mach with no canopy and was okay).
The only real problem is actually running at those speeds without your muscles overheating, and your legs shattering due to running that fast. Speedsters generally go much faster than mach 1 though, and bring up problems that have more to do with relativistic physics than biology.
At high enough speeds differentiating organs with molecules colliding into each other becomes a moot point.
On September 08 2016 08:59 Epishade wrote: What if the air surrounding you is hotter than body temperature? Would you want to expose less of yourself then?
No. And the guys talking about covering up and why you can't survive, are only partially correct. While you will eventually die of dehydration, your body only really r equires the important bits to stay cooled. You can survive for a while in an environment hotter than your body temperature as long as you drink enough water. The evaporating water will still cool your skin, which allows you to shed heat from your blood, and keep your core cooled enough for a while. Eventually thermodynamics ensures us that it will all even out, but you only have to survive one night. Of course, the hotter the surroundings, the more liquid is required to keep this process going, and there will be a point where your body will simply stop being able to cool down. But that isn't at 38 degrees ambient temperature (not sure how hot it can get before an average human stops being able to cope for 8 hours). You won't be comfortable, and you'll need to drink lots of water, but the basic principle of maxing surface area, and thus perspiration, stay the same.
On September 08 2016 13:32 Zambrah wrote: What are all of the specific adaptations that would allow a Speedster (aka someone with Super Speed) to go at the speeds they go (lets assume the speed of sound, for simplicity) without the general physical issues caused by going at these speeds.
For example, one of the most common issues is the issue of friction burning your clothing off.
What does your skin need to be like? Your organs?
What are the mental effects?
Inquiring minds want to know.
I think we should talk about acceleration and the g-forces as much (if not more) as we talk about maximum speed.
Also, can we talk about conservation of momentum? When they go from 0 to speed of sound in the fraction of a second, what takes the recoil? The ground? They'd leave craters behind themselves, or just slip as the sideways-to-downwards force would have to be huge.
Even assuming they coincidentally always stand on super firm ground, and has special shoes with near infinite grip, there is also the issue of conservation of angular momentum: if the force is only applied at the feet, and pushing sideways so much stronger that gravity really isn't a factor, why doesn't the speedster just start rotating?
And seeing that they move much faster than gravity, what brings them back down to the ground for the next step?