Measuring relative coldness (temp, not miserable in-laws)

McGraw

McGraw

McGraw

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On the radio other night someone rang up and asked this question:

If it was 0c last night and tonight it’s twice as cold, how cold is it tonight?

They converted it to Fahrenheit on the radio which I think is wrong.

I think you have to have a baseline temp for neither cold nor hot which is different for each individual.

Let’s say 18c is your neutral temp, -18c would be twice as cold as 0c....

Thoughts?
 
Twice as cold would be -136.5 decrees celcius.

Absolute zero is 0 kelvin which is approx -273 degrees celcius. So half as cold as 0 degree celcius would be halfway between 0 and -273.)

I'm probably wrong but that's my effort at it :)
 
The only accurate way to do it would be in terms of the energy levels of particles, i.e. what temperature actually is.

[EDIT: I see that two people who posted while I was writing this and making a cup of tea have said the same thing as the above, assuming that Kelvin is a linear scale]

Any subjective assessment is just that - subjective. Putting any figure to it is dishonest because it's portraying a subjective assessment as an objective measurement. It also wouldn't be a linear scale even if you pretend there is a scale. It would also depend greatly on a person's current circumstances and what clothing they have on. It's dishonest and nonsensical to pretend it's a measurement of any kind.

I personally find ~20C to be a comfortable temperature in light clothing when awake and doing minimal activity. So by your method my baseline temp is 20C.

If I'm tired or ill in some ways I find 20C cold in light clothing when awake and doing minimal activity. So by your method the temperature of the real world is defined by how tired I am and 20C is significantly colder than 20C.

If I put on clothing with much lower thermal conductivity and walk briskly, I can find temperatures below 0C comfortable. The lowest temperature I've found comfortable was about -5C when I was out and about on a particularly cold night. Good boots, two pairs of socks, long johns under my trousers, 3 layers on my torso including a good coat with a good seal, good gloves, a good hat. -5C was absolutely fine when walking around dressed like that and feeling awake and well. So by your method -5C is the same temperature as 20C.

But my nose was very cold because that wasn't covered. So by your method being near my nose somehow caused the real world to become many times colder for a fraction of a second, with masssive and extremely rapid fluctuations in temperature in the real world as I walked.

Etc.

As an addendum, even if you ignore all that it still wouldn't be a linear scale. In the same circumstances in which a particular person finds 18C comfortable they would perceive -18C as being many times colder than 0C. 0C would be cold but tolerable. -18C would be fatal in a short period of time. It's far more than twice as cold, subjectively.
 
McGraw said:
On the radio other night someone rang up and asked this question:

If it was 0c last night and tonight it’s twice as cold, how cold is it tonight?

They converted it to Fahrenheit on the radio which I think is wrong.

I think you have to have a baseline temp for neither cold nor hot which is different for each individual.

Let’s say 18c is your neutral temp, -18c would be twice as cold as 0c....

Thoughts?
Click to expand...

For different people, it is different. Some women can tell you that 25°C would be their neutral temperature.
Also, relative humidity makes you feel the same temperature in a different way.
0°C in a desert is something different compared to 0°C in the middle of the ocean.
The question is invalid, me thinks, too.
 
I thought that senses work on a logarithmic scale, so 10x the number of of photons = double the brightness, 10x the sound energy = double the volume...dunno what that means for temperature, but I'm sure some clever person could have a stab at it
 
Pipe & Slippers said:
I thought that senses work on a logarithmic scale, so 10x the number of of photons = double the brightness, 10x the sound energy = double the volume...dunno what that means for temperature, but I'm sure some clever person could have a stab at it
Click to expand...

Subjectively perceived temperature isn't directly based on actual temperature in any way. Not linear, not logarithmic, not anything. Subjectively perceived temperature is primarily based on the rate of heat transfer, at least in normal circumstances(*).

You can test this directly by experiment in your own home, if you like. Get a piece of material with a relatively high thermal conductivity (e.g. steel) and a piece of material with a relatively low thermal conductivity (e.g. wood) of the same size, put them both in your fridge, leave them for a while so they both cool down to the temperature of your fridge, take them out and hold each one in your bare hand (or in contact with any skin). The steel will feel much colder to you than the wood even though you know that they are at the same temperature.

* It's quite common for people with severe hypothermia to feel hot and take off their heavier clothing and sometimes all their clothing. I don't recall why, but it's definitely a thing that happens.
 
4K8KW10 said:
There is a good article at http://betweenborders.com/curiosities/twice-as-cold-as-0°c/

But the thing is that in the question it is said "tonight it is..." So, it is impossible to be minus 136°C. There is no such temperature on Earth.
Click to expand...

There is such a temperature on earth.

"Low Temperature Laboratory recorded a record low temperature of 100 pK, or 1.0 × 10−10 K in 1999." Which is about -273.

It's worth noting the lowest recorded naturally occurring temperature on the surface was nearly -100 so not too far off your 'impossible' number.
 
humidity is what makes temperature un/comfortable

40 degrees C with 50% humidity is more pleasurable than 22 degrees C with 90%+ humidity

Same with cold, some cold is better than other
 
Dis86 said:
There is such a temperature on earth.

"Low Temperature Laboratory recorded a record low temperature of 100 pK, or 1.0 × 10−10 K in 1999." Which is about -273.

It's worth noting the lowest recorded naturally occurring temperature on the surface was nearly -100 so not too far off your 'impossible' number.
Click to expand...

Naturally occurring is not nearly minus 100°C but between minus 90°C and minus 80°C. And it happens very rarely in Antarctica during its night winter..
The question is invalid. It lacks context.
 
4K8KW10 said:
Naturally occurring is not nearly minus 100°C but between minus 90°C and minus 80°C. And it happens very rarely in Antarctica during its night winter..
The question is invalid. It lacks context.
Click to expand...

"More recent work[5] shows many locations in the high Antarctic where surface temperatures drop to approximately −98 °C"

And that's just from Wikipedia!

However yeah, question is poop.
 
cheesyboy said:
Two-jumper weather is twice as cold as one-jumper weather.

it's not rocket science.
Click to expand...


Its not strict physics, But In terms of describing weather. This is about as good a definition as it gets. :p

Even takes into consideration all the other relevant factors such as humidity, wind chill and so on..
 
I don't think it's valid question...

However saying that, I can see 2 potential answers that make sense to a degree.
1) -137C (as per the Kelvin descriptions previously)
2) -37C - Assuming a linear scale (which I'm not sure it is), but this would be the temperature that is "twice as far" away from body temperature.

Either way, I feel the only real way to answer the question, would be to consider the amount of heat energy that is present, and option 1 is essentially doing this (again, assuming a linear scale)
 
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