Situation Question - Sudden Temperature Change?

[Kitsune]

Assume you have a group of individuals holding captive a concert hall.
Assume that they are dressed in fatigues.
Suddenly, the temperature starts dropping in the hall.
Using Fahrenheit, assume that within one minute drops from 80 degrees to -20 degrees.
How do you think these captive takers might react?

[Borgholio]

Depends on their convictions. If they're the stereotypical Islamic terrorists they'll probably try to murder the hostages as soon as they feel threatened by the dropping temperature. On the other hand if they're just disgruntled postal workers who want some attention, they'd probably give up once their noses started to freeze.

[Mr Bean]

Assume you have a group of individuals holding captive a concert hall.
Assume that they are dressed in fatigues.
Suddenly, the temperature starts dropping in the hall.
Using Fahrenheit, assume that within one minute drops from 80 degrees to -20 degrees.
How do you think these captive takers might react?

I'm trying to calculate the energy requirements to go from 80 to -20 in seconds and my napkin calculations show that the answer is that everyone starts convulsing from the thermal change.

Put it another way, if I had water at 0*F and tossed you into it what would your body do?

[Iroscato]

Cardiac arrests all round? I really can't imagine any other reaction to such an extreme drop in temperature...

[SCRawl]

This doesn't seem all that remarkable to me, in terms of temperature change. I experience the same thing every winter when I step outside from a warm house. Granted, my house isn't usually that warm -- I keep it around 70F, or about 20C -- and it's often below -20F (or -29C) when it gets cold. I will generally be dressed for the occasion, though, unlike the fatigue-wearing group in the OP. Achieving this with air conditioners might be a difficult feat, but I seriously doubt that any healthy person would die from it in a few minutes.

[Mr Bean]

This doesn't seem all that remarkable to me, in terms of temperature change. I experience the same thing every winter when I step outside from a warm house. Granted, my house isn't usually that warm -- I keep it around 70F, or about 20C -- and it's often below -20F (or -29C) when it gets cold. I will generally be dressed for the occasion, though, unlike the fatigue-wearing group in the OP. Achieving this with air conditioners might be a difficult feat, but I seriously doubt that any healthy person would die from it in a few minutes.

Your missing the temperature change element. You still have all of your body heat and clothing heat when you go from 70*F to -20*F. If you jumped into water that's at 40*F something humans can run around in for hours and be fine you will be dead in minutes. Likewise this situation, this opera house and everything in it is being excused via refrigeration or freeze ray or magic to a massive change in temperature. This temperature is acting on them, on the seats on their clothing and the air itself. Let me ask you how you would be doing in -20*F after twenty minutes in your short sleeves? Because that's the equivalent.

Going from 70*F to -20*F ignores all that lovely body heat you breath with you compared going from 70*F to 40*F which kills you dead fast.

[Broomstick]

Put it another way, if I had water at 0*F and tossed you into it what would your body do?

I'd yell >ow!< as I hit the surface of the ice - you do know water at that temperature is a solid, yes?

Healthy people can survive such a temperature change. Aside from the various polar bear plunges around the world, there is also the 300 club, where people at the South Pole subject themselves to a 300 degree Fahrenheit temperature change. I wouldn't advise something like that if you're at higher than normal risk for something like a heart attack, but like I said, healthy people can cope with it.

[Mr Bean]

Put it another way, if I had water at 0*F and tossed you into it what would your body do?

I'd yell >ow!< as I hit the surface of the ice - you do know water at that temperature is a solid, yes?

Can be a solid under the right conditions you can supercool water but point taken I should have said 33*F

And again this is just air temperature. There's a difference between going into cold air and enduring direct contact with a cold item. Conductivity is king and this kind of temperature change should induce all sorts of nasty body side effects.

[Sky Captain]

Hypothermia would soon take effect in such conditions without adequate clothing. Temperature change itself shouldn't cause any serious problems. If during cold winter morning with -29 C I have to go outside for a minute or less to take something from garage or to take the garbage bag out to large container there is similar temperature change from + 20 C house to -29 C outside and nothing bad happens to me even though I have only t shirt and shorts. Humans don't loose heat that quickly.

[LaCroix]

Thermodynamically, you can only add heat, but not add "cold". So you would need to insert as much cold air at -120° into the room as it already contained 80°F air, (ignoring everything except the air for simplicity) to gain a -20° average temperature air mixture.

Given the volume of an average concert hall, I feel that would be a pretty stiff wind coming out of the vents to achieve that kind of air exchange. People standing nearby such a vent (the air is -120° at that point, and moving extremely fast, on top) will have much worse problems.

[SCRawl]

This doesn't seem all that remarkable to me, in terms of temperature change. I experience the same thing every winter when I step outside from a warm house. Granted, my house isn't usually that warm -- I keep it around 70F, or about 20C -- and it's often below -20F (or -29C) when it gets cold. I will generally be dressed for the occasion, though, unlike the fatigue-wearing group in the OP. Achieving this with air conditioners might be a difficult feat, but I seriously doubt that any healthy person would die from it in a few minutes.

Your missing the temperature change element. You still have all of your body heat and clothing heat when you go from 70*F to -20*F. If you jumped into water that's at 40*F something humans can run around in for hours and be fine you will be dead in minutes. Likewise this situation, this opera house and everything in it is being excused via refrigeration or freeze ray or magic to a massive change in temperature. This temperature is acting on them, on the seats on their clothing and the air itself. Let me ask you how you would be doing in -20*F after twenty minutes in your short sleeves? Because that's the equivalent.

Going from 70*F to -20*F ignores all that lovely body heat you breath with you compared going from 70*F to 40*F which kills you dead fast.

You seem to be talking about several different things here.

If I were to jump into 40F water, yes, that would be very shocking, but the reason for that is because the heat capacity of water is so much higher than air.

I'm not sure why "this opera house and everything in it" has to be dropped to -20F in that minute -- it seems to me that it's the air temperature that's been changed, which would likely be accomplished by replacing the 80F air with -20F air (or something like that). If we're talking about dropping everything (including the people?) to -20F, then yes, you will have a number of corpses on your hands, but this requires an act of magic rather than one of engineering. Continuing to pump cold air into this environment (without magically reducing everything to -20F in one shot) would eventually drop everything in it to -20F, but this would take time -- enough time for even people in their shirt sleeves to get out of there.

[Mr Bean]

[quote="SCRawl"

You seem to be talking about several different things here.

If I were to jump into 40F water, yes, that would be very shocking, but the reason for that is because the heat capacity of water is so much higher than air.

I'm not sure why "this opera house and everything in it" has to be dropped to -20F in that minute -- it seems to me that it's the air temperature that's been changed, which would likely be accomplished by replacing the 80F air with -20F air (or something like that). If we're talking about dropping everything (including the people?) to -20F, then yes, you will have a number of corpses on your hands, but this requires an act of magic rather than one of engineering. Continuing to pump cold air into this environment (without magically reducing everything to -20F in one shot) would eventually drop everything in it to -20F, but this would take time -- enough time for even people in their shirt sleeves to get out of there.[/quote]
Keep in mind the time frame, one minute or sixty seconds to produce that kind of tempature change in sixty seconds would require either magic or massive fans connected to a massive -30 or -50 air being dumped into the oprea house.

Put it another way, how well would you be doing in shirt and pants with a 80mph -30*F hitting you?

[SCRawl]

You seem to be talking about several different things here.

If I were to jump into 40F water, yes, that would be very shocking, but the reason for that is because the heat capacity of water is so much higher than air.

I'm not sure why "this opera house and everything in it" has to be dropped to -20F in that minute -- it seems to me that it's the air temperature that's been changed, which would likely be accomplished by replacing the 80F air with -20F air (or something like that). If we're talking about dropping everything (including the people?) to -20F, then yes, you will have a number of corpses on your hands, but this requires an act of magic rather than one of engineering. Continuing to pump cold air into this environment (without magically reducing everything to -20F in one shot) would eventually drop everything in it to -20F, but this would take time -- enough time for even people in their shirt sleeves to get out of there.

Keep in mind the time frame, one minute or sixty seconds to produce that kind of tempature change in sixty seconds would require either magic or massive fans connected to a massive -30 or -50 air being dumped into the oprea house.

Put it another way, how well would you be doing in shirt and pants with a 80mph -30*F hitting you?

To answer your last question first, not very well. No one would be doing very well.

But let's try a few numbers.

Some Google-fu has led me to some exhaust fan specs. Some of these things are in the tens of thousands of cfm. The Sydney Opera House is in the neighbourhood of 880k cubic feet. Let's be conservative and say that we need 200 fans, each capable of moving 10k cfm -- 100 fans to move the hot air out, and 100 fans to move the cold air in -- and we have an opera house with one million cubic feet of volume. We will ignore inefficiencies, since I don't know how to handle them anyway. I don't know where the cold air would be coming from, but we can just assume that this opera house is in Alaska, the month is February, and for some reason they had the heat cranked up to 80F before this whole operation began. That would solve the problem of "how do we do this?", and everything inside doesn't have to be reduced to -20F -- just the air, which was (I think) the intention of the OP.

(Some more quick math -- if this fan has a radius of 2 feet, then it has to move a cylinder of air 833 feet long in order to move 10k cubic feet in one minute. This translates into roughly 10mph, which is brisk but manageable.)

So we've come from needing -30F at 80mph to a more "realistic" -20F at 10mph in my shirt sleeves. I would be very unhappy to be in this environment, to be sure, but I could manage it for a minute or two, certainly long enough to kill a couple of hostages and then beat it for the exits. We don't need to think about anyone dying from a heart attack.

[Kitsune]

A couple of notes. . . .
1. I am assuming something a little smaller than Sydney Opera house
2. I was assuming that at least part of the heat is due to body heat of a large.
Been in other venues where the AC just cannot keep up with body heat.

[Simon_Jester]

You didn't clarify the most fundamental question we have, though.

Did the air temperature suddenly change sharply? Or did the temperature of literally every object in the room change, including people's bodies? In the former case, people are sharply inconvenienced and very startled and uncomfortable, and will wind up dying of hypothermia if conditions persist for any great length of time. In the latter case, everyone is flash-frozen solid and dies instantly.

[Kitsune]

Ah, I think it would be air temperature. Much less energy state change to drop the temperature of the air than everything