[Elecraft] Generic words on temperature

[Louandzip]

 In years past, we had a spec where 60C was the the hottest temp allowable on any exposed accessible surface.  On a metal surface with high thermal conductivity and significant thermal mass (e.g. aluminum heat sink), it feels very warm to the touch, only starts to cause pain after many seconds, and causes pain long before causing injury.  That spec might be codified in some safety standards somewhere. 

A piece of wood or plastic at 60C just feel warm.  Heat and temperature are very different.  They have different dimensions and units. 

Lou W7HV

    On Sunday, July 4, 2021, 4:47:36 PM MDT, Francis Belliveau <f.belliveau at comcast.net> wrote:  
 
 All,
I am taking this off-list since it is so far off topic.

What I said seems to have been somewhat misinterpreted.  

1. "Threshold of pain" means it starts to hurt, not "I can't stand it any more".
2. The surface temperature of a child's forehead when running a fever of 106 degrees is less than 100 degrees.  The 106 is an internal temperature.
3. This is a "rule of thumb", not an absolute.  Run the experiment yourself:

  * Come up with a way to measure the temperature of a hot surface.  Maybe an over window could be used, but you need to measure the surface temperature.  Using a forehead thermometer will not work since it has bee calibrated to read internal temperature based on the cooler external temperature.

  * Heat the surface to 99 degrees and see how it feels.

  * Then try it again at 100 or 101 degrees.

Yes, individuals can handle much hotter temperatures.  I once saw somebody reach into a hot fish-frier and come out unburned; but he had been working in the frying industry for years and had built up the ability to to that.
This "rule of thumb" is based on a "normal average".

73,
Fran


> On Jul 3, 2021, at 19:52, David Woolley <forums at david-woolley.me.uk> wrote:
> 
> 100°F is well within the survivable body core temperature range, so it should never trigger pain receptors.
> 
> In fact, I believe it was defined based on the nominal core body temperature of a cow.
> 
> Did you mean 100°C?
> 
> -- 
> David Woolley
> 
> 
> On 04/07/2021 00:03, Francis Belliveau wrote:
>> Another rule of thumb for those who care.
>> When you hold a finger on something and it is 10 seconds to pain threshold, that location is about 100 degrees F.
>> This is not an absolute constant, but I have checked it a few times since I was told that, and it seems to be true for me.
> 
> 
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