Or, no soup of you, either.
This probe was on a machine that I designed about 10 years ago. The head was approximately the size of a dime. The probe could change temperature at a rate of about 10 to 15 deg C per second, and would lock on to a temperature within 0.5 deg C. The machine was calibrated using a lab thermometer tracable back to NIST standards.
You can google all you want, but I can tell you from experience that 47 deg C on this probe was pretty F-ing hot, even for folks who work with this stuff all day long and get somewhat desensitized to it. Not only is it painfully hot, but it’s painful enough that I would not want to keep my finger on the probe at that temperature. I’m sure I did keep my finger on it once or twice at that temperature, but only while the machine was commanded to go to that temperature for about 3 seconds at the most.
The machine had a safety cutoff at 50 deg C (it would shut off the heating element and would require a reset before you could use it again). Above this temp you actually damaged the skin, which rendered further testing on the subject useless. I only got the machine to 50 deg C a few times on my own skin, mostly while I had a software bug that would cause the machine to rapidly get hotter and hotter until the safety cutoff turned it off. Even though the machine was at 50 deg C for much less than a second, I still jumped up out of my chair and danced around the lab saying a few choice words.
If your drunk enough you can. Or I guess these folks pass out drown, and cook.
It happens around here about every 2 years or so.
It makes for a bit of a predicament for the rescuers. Can’t just grab an arm or leg, because that’s all you get.
24-48 hours in 105f cooks people up pretty good.
Blake, this is GQ, not GD.
[slight hijack]I was speaking of the typical American’s perception of temperature, of which I am unfortunately afflicted. Raised with Farenheit, not having any experience with Celsius, yes, I could be considered ignorant by Celsius users, but in order for me to properly appreciate what a temperature is, I have to see it expressed in Farenheit.
When I lived in extreme northwest Washington State, one of my favorite radio stations to listen to was in Vancouver, B.C. They would give the high/low/current temperatures in Celsius…and I found myself trying to convert the temperatures given into Farenheit - incorrectly, it turned out.
Yes, a good number of Americans are afflicted with Farenheit tunnel vision. But we’re also afflicted with inches, feet, yards, and miles. If a Canadian friend told me it was 12 kilometres to his house, it would be prudent for me to do the conversion so I could get there using my known measurement system. Same with the temperature conversion. No, that’s not your problem. Yes, it’s mine, and I admit my ignorance in that matter.
In other words, get over it. I’m trying to understand so I can grasp the concept. That’s fighting ignorance. That’s what we’re all about. [/sh]
No. But you sure have an amazing ability to not comprehend.
Let me dumb it down.
- OP asks about immersion in water.
- In partial response to that question engineer_comp_geek states that a nickel sized probe at 47oC would be inevitably and unavoidably very painful to touch.
- I pointed out that that makes no sense since anyone living in air temps of 47oC would be registering everything as very painful. That is npot even close to true.
- engineer_comp_geek also states that a small probe at 42oC would be registered as so painful by most people as to demand the contact be ceased immediately. That alos makes no sense for the reasons I gave.
- You then came in and said that my reasons why that wasn’t true of small metal probes were faulty because of some shit to do with immersion in water.
Note that my reasons never, ever, ever had any bearing on immersion in water. I was clearing up an erroneous claim made about the small metal probes being painful.
Sheesh. You could have just read the thread yourself.
The problem is that as I have pointed out, that makes no sense and flies in the face of thew known facts.
How do you explain that people are able to touch metal objects even when the air temperature is above 50oC if 4667oC is extremely painful?
This is GW, not IMHO. Unless you have a reference to support that claim it’s just provably erroneous anecdote. You obviously misremembered.
Surely this research was published. It can’t be that hard to provide a reference.
Blake Let me “dumb it down” for you. Don’t use this tone in GQ.
smclem GQ moderator
Basically, there are four types of heat receptors in human skin, called TRPV1, TRPV2, TRPV3, and TRPV4.
Cite: http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/P/Pain.html
TRPV1 is the one we are mostly concerned with here, since it activates at approx 43 deg C. The above cite also mentions that TRPV1 “Also activated by capsaicin, the active ingredient of hot chili peppers” which is why spicy food tastes ‘hot’.
Cite: Clinical Science | Portland Press
Cite: http://www.the-scientist.com/2005/03/28/S20/1/printerfriendly
Cite: http://www.neuro.wustl.edu/neuromuscular/mother/mpain.html
(under the heading “pain stimuli” and the sub-heading “temperature”)
Google terms like “TRPV1” and “heat pain threshold” for more cites.
For the record, Blake, you did make a number of comments on pain thresholds involved with water, immersion, and bathing. II don’t mind if you have departed that subject in favor of a more easily defensible one, but do not pretend as if the record does not contain strong comments from you on immersion in water:
engineer_comp_geek is correct. He has worked in the field, as I do currently (albeit tangentially). Let me state again:
There are TWO definitions of ‘heat pain’ that may be confusing people:
-
Heat pain threshold: This is the temperature at which a heated stimulus is first perceived as painful, often the instruction to experiment participants is to say when the stimulus first begins to cause them discomfort.
-
Heat tolerance threshold: This is the temperature at which the partipant can no longer stand to remain in contact with the thermal device.
There are countless references that support the heat pain thresholds stated by engineer_comp_geek. Well, not literally countless, but it would take you a while to read 'em. It would also get pretty boring 'cause they all say basically the same thing. A few examples from thousands:
Essick et al. (2004), Som Mot Res 21: 159-175. Heat pain thresholds on various facial sites lie in the range 42-45degC. These values are also consistent with Becser et al. (1998; Cephalagia 18: 574-582) who also studied facial sites.
Extrafacial sites: Lautenbacher & Rollman (1993; Pain 53: 255-264) found heat pain thresholds in the range 43-44degC for hand and foot, for both male and female subjects. Similarly, Lautenbacher & Strian (1991; Percept Psychophys 50: 179-183) found heat pain thresholds of c.45degC on hand and foot, for males an females.
Small differences in reported t/holds can be attributed, for the most part, to differences in testing methodology.
In fact, the research is at the stage that the basic results are no longer in question, and experiments are now somewhat more esoteric, such as looking at threshold variations in different racial groups, and people with different hair colour (true!).
Some studies do use temperatures right at the upper limits of tolerability, e.g. (49degC - Coghill et al., 2003 ), although this is usually for ‘special’ reasons. (The Coghill study uses brain imaging, which is a fairly blunt tool in a lot of ways, and a technique that really likes strong brain activity, as induced by a powerful stimulus).
And Blake, in your cite that mentions 43degC as showering temperature, this is probably not the temperature measured at the body surface. It is probably the thermostat temperature, and the water temperature will have dropped considerably as it sprays toward the bather. In fact, Herrman et al. (1994; Physiol Behav 56: 1003-1008) looked at preferred temperatures in showering, finding ‘Preferred water temperature was slightly warmer [than neutral] and led to slightly elevated skin temperatures, warmth, and pleasantness estimates’. This suggests that the 43degC you mention is unlikely to be the temperature at the body surface. However, I cannot be arsed to go to the library to actually read the paper (I’ve just read the abstract), but I might do at some point. Incidentally, the authors also note that showerers were very sensitive to small changes in water temperature, suggesting that it would be tricky to surreptitiously boil someone to death in a shower at least…
Blake, this may sound tendentious, and if so I apologise, but when you say that you worked in air temperatures of over 47degC (and later mention temperatures of 50degC), I wonder if, first, you are reporting the most extreme case you experienced, rather than a commonplace, and secondly if the temperature as it was reported to you at that time may have been exaggerated. Of course I don’t know where you were living, but I do know from experience that extremes of hot and cold are very often exaggerated, often through unreliable measurements, and with no intent to deceive.
I find it entirely believable that if the air temperature was 50degC (and I know it does happen, in some parts of the world), metal objects would be uncomfortably or painfully hot to touch.
Where I live it is commonly at 33 C, sometimes higher. Metal that has been in the sun for a short time at this temperature can be hot enough so you cannot touch it. If left for a while I’m sure it will burn you.
The question’s been answered, but while reading through this thread I thought it would be easy to do a simple little trial at work to compare the cited pain thresholds for those who don’t want to look at the technical papers.
We have a water heater, and a dissolved O2 probe that also records temperature, and a sink. I can’t vouche for the temp probe’s pinpoint accuracy, but it was reading exactly the same as another glass thermometer I had… I used that one for the last pic because the probe cuts out at 46ºC. I turned on the hot for a few minutes, then ran the water over my hand and forearm while holding the probe in the same water, and adusted the heat by turning the cold up and down. My pictures (temperature is the smaller number):
The heater:http://img349.imageshack.us/img349/6808/heater0dm.jpg
Here was what I considered a luke-warm bath temp:http://img349.imageshack.us/img349/6227/lukewarm6zn.jpg
Here’s a very warm to hot temp:http://img349.imageshack.us/img349/4210/hot8kn.jpg
This was definately too hot for me; I had the will power to hold my hand under this for maybe 5 seconds before I couldn’t stand it anymore. Right now half an hour later I can still feel it on my hand and arm while I type this:http://img349.imageshack.us/img349/2521/5seconds8fr.jpg
Here is what the heater is putting out - 56ºC(I couldn’t find the temperature setting so I just ran the hot water straight (notice I’m keeping my fingertips out of that water - it would have burned me:http://img349.imageshack.us/img349/1738/maxtemp1bf.jpg
And here is a warning label I found on the heater:http://img349.imageshack.us/img349/3107/warning1uo.jpg
I found the water painful around 43ºC, and absolutely intolerable for more than a few seconds at over 45ºC. Oddly I could hold the hot, dry metal water spout at the 56ºC temperature for a short time; I could feel my hand heating up and it took about 4 seconds before the spout was too hot to keep holding. I think the dryness of the tap combined with using the relatively thick palm skin only let me do this while the faster heat transfer of the actual water over thinner skin (in between fingers for example) made the same temperature too much to handle with my hand in the water pretty much instantly. You only have to hold a door knob for perhaps 1/2 second to open the door, while I found it took about 4 seconds for a 56ºC dry metal object to get painfully hot in my hand… meaning you can touch a door handle that hot easily, but it hurts to hold it for a long time… then again:
Also remember that an air-heated knob will lose heat to your hand much faster than my hot water tap which continually had the heat replaced by more flowing water. When I left the water running, that 56ºC spout just got too hot to hold, BUT when I turned the water off and grabbed it, I felt it warm up as before, but it didn’t get as hot and it started to cool down at about 12-13 seconds… IOW the non-reheated 56 degree (initially) metal spout didn’t burn me as predicted. So from this, it seems quite reasonable that water in the mid 40’s can be painfully hot when it’s flowing over you or you’re imersed in it, while you can still open and even hold onto air-heated door knobs in the mid 50’s without feeling pain.
One more thing: I ran the 56ºC for several minutes into an over-flowing ceramic cup… I could drink that water no problem. 43-45ºC was painful in my hand, but 56ºC was just a good hot coffee temp in my mouth.