What-If 0115: "Into the Sun"

[Mikeski]

You made the exact argument people use to say Celsius makes no sense, and then claimed there is no such argument.

There is a suitably large range between "Celsius does not map to natural (English) language as well as Fahrenheit", and "Celsius makes no sense." There might even be more than one level of argument between them!

[Mambrino]

That doesn't sound especially rigorous. Why 0 °F is whatever it is, and not -1 °F?

Of course it's arbitrary, but so is every other base unit. Except time, actually, which at least corresponds to the natural length of a day even if that isn't quite as constant as we'd like it to be. Whatever solution freezes at 0° in a particular system, that particular solution at that particular pressure is unlikely to be quite what you actually have on hand in most real-life situations. Nothing important happens outdoors at exactly 0°C, because wind and current and salinity and pressure and the temperature of the ground and at different places in the atmosphere all play their parts, so we can have snow above 0°C and rain below 0°C, we can have ice on the roads above 0°C and water below 0°C.

surely it feels more connected to everyday scientific phenomena

Only because we use K in science and K is designed to be the same size as °C.

I thought I had written there a line about every scale being arbitrary. Apparently I forgot it, then.

By everyday, I meant more like difference between a fridge and a freezer, or what happens to water in a kettle when it starts boiling. While all your points are correct and valid, I've personally found all that stuff conceptually more sensible and maybe even easier to manage with °C ("yes, it's not incorrect to say that the water starts to boil at 100°C, but actually the pressure counts, too, so on the top Mount Everest it's different. Actually, the pressure is quite important thing to take into account when talking about this stuff, welcome to physics class").

Of course I've never used Fahrenheits that much, so maybe it's just what you grew up with and are accustomed to use.

(Though speaking of Kelvins defined to be same as C, maybe they had a point when they chose to base K with Celsius.)

(Also, 100°C feels like ... quite pleasant actually, for air temperature. Depends on how you define "extended periods of time". A couple of hours?)

I dare you to try it sometime. You would last minutes, tops.

(Also, 100°C feels like ... quite pleasant actually, for air temperature. Depends on how you define "extended periods of time". A couple of hours?)

I dare you to try it sometime. You would last minutes, tops.

Stand around in 100 degree heat? I'll pass. Pork and beef are smoked at a temperature of only 105-110. The craziest Finnish sauna you can buy in the USA only goes to 90. "Quite pleasant" isn't the usual idea for a sauna; "sweating your ass off" is.

I have often been in a sauna at 105-110­°C. It is comfortable if you are used to being in a sauna. If you aren't then it is uncomfortably hot and nauseating. Since I haven't been in a decent sauna in years I expect it would once again be uncomfortable.
Sweating your ass off and quite comfortable can be the same event. For me a sauna is meant to be relaxing, while sweating my ass off.

Neil got it. I think the generally accepted line between "uncomfortable" and "crazy" is somewhere +120°C (and then you're talking about minutes). About 90-100°C is still normal, though.

And while I did say "couple of hours", now that I'm actually thinking about it, I must backtrack a little: that would include breaks for drinks and showers (so a slight overestimation). While the whole occasion might take a couple of hours, continuously in the heat room maybe 20-30 min tops at time (caveat: that obviously depends on the temperature and stuff, probably much shorter if it's much over 100°C, maybe even longer if it's 70-80°C). And of course, the humidity of air and the ventilation count, too: the important bit is whether your body is able to manage its temperature by sweating.

Edit: Speaking of mapping to natural language, we the Celsius users manage with "about/over/under (rounded to nearest divisible by 5)". Is it that much a difference? I don't know.

[stoppedcaring]

I think the generally accepted line between "uncomfortable" and "crazy" is somewhere +120°C (and then you're talking about minutes). About 90-100°C is still normal, though.

And while I did say "couple of hours", now that I'm actually thinking about it, I must backtrack a little: that would include breaks for drinks and showers (so a slight overestimation). While the whole occasion might take a couple of hours, continuously in the heat room maybe 20-30 min tops at time (caveat: that obviously depends on the temperature and stuff, probably much shorter if it's much over 100°C, maybe even longer if it's 70-80°C). And of course, the humidity of air and the ventilation count, too: the important bit is whether your body is able to manage its temperature by sweating.

The point being that your body needs to work overtime to keep itself regulated once the ambient temperature exceeds body temperature. 0 and 100 are fairly close to the temperature extremes most people can tolerate.

[Mambrino]

I think the generally accepted line between "uncomfortable" and "crazy" is somewhere +120°C (and then you're talking about minutes). About 90-100°C is still normal, though.

And while I did say "couple of hours", now that I'm actually thinking about it, I must backtrack a little: that would include breaks for drinks and showers (so a slight overestimation). While the whole occasion might take a couple of hours, continuously in the heat room maybe 20-30 min tops at time (caveat: that obviously depends on the temperature and stuff, probably much shorter if it's much over 100°C, maybe even longer if it's 70-80°C). And of course, the humidity of air and the ventilation count, too: the important bit is whether your body is able to manage its temperature by sweating.

The point being that your body needs to work overtime to keep itself regulated once the ambient temperature exceeds body temperature. 0 and 100 are fairly close to the temperature extremes most people can tolerate.

My original response was that "how 100°C feels like" can be quite meaningful thing to ask (there's difference between sticking one's head in a 100°C room instead of hand in boiling water), and then there was some discussion about sauna.

I can agree 100°F is a sort of sensible temperature to pick up for temperature scale for human use, but the point was whatever means to "tolerate"?
WolframAlpha tells me 0 °F = -17.778 °C. How that's a meaningful extreme? For naked human being, frostbite and hypothermia could be a problem before it gets that low. Otherwise, it just a question of suitable clothing. (Of course, the time spent in such low temperatures is essential; swimming in 0 -- 4°C water is a thing, too, but you wouldn't want to stay there too long involuntarily.)

If it's rather a question of extremes in the sense of "the coldest in the winter" and "hottest in the summer" where most people live, as someone proposed, there could better answers to that than a guess by some dude from the 18th century Danzig, because most places are not Danzig. Defining the "extreme cold for humans to tolerate, worth of being called the 0°F" that way feels a little silly, even if it wasn't terribly bad guess either. Why it'd be a superior guess? Maybe if there where statistics for optimal 0 in that sense. Or what's the point, that's not going to influence anything.

[gmalivuk]

The 0 in Fahrenheit came from the lowest temperature to which Daniel Fahrenheit could reproducibly cool ammonia brine without modern equipment, though there is some speculation that it was also based on the lowest temperature reached in his hometown every year. 100F was defined as a temperature fairly close to human body temperature. So that's why it matches heat and cool extremes pretty well.

I remember reading that originally 0°F was cold ammonia brine (ice, water, and ammonium chloride in a 1:1:1 ratio), 32° (2^5 more) was ice water, and 96° (2^6 more still) was (axial) body temperature. Powers of 2 (and sometimes 3) were the norm for many units of measurement for much of the world, being so easily reproducible precisely.

(Though speaking of Kelvins defined to be same as C, maybe they had a point when they chose to base K with Celsius.)

They had as much of a point with that as they did defining the Rankine scale based on Fahrenheit.

Obviously people using Celsius for everyday purposes should use K for absolute temperatures, but just as obviously people using Fahrenheit should use °R instead.

Neil got it. I think the generally accepted line between "uncomfortable" and "crazy" is somewhere +120°C (and then you're talking about minutes). About 90-100°C is still normal, though.

And while I did say "couple of hours", now that I'm actually thinking about it, I must backtrack a little: that would include breaks for drinks and showers (so a slight overestimation). While the whole occasion might take a couple of hours, continuously in the heat room maybe 20-30 min tops at time (caveat: that obviously depends on the temperature and stuff, probably much shorter if it's much over 100°C, maybe even longer if it's 70-80°C). And of course, the humidity of air and the ventilation count, too: the important bit is whether your body is able to manage its temperature by sweating.

If there's more than 1.8% humidity (16.6°C dew point), your body cannot even in theory cool itself by sweating at 100°C. With 0% humidity, that happens at 127°C.

[Barstro]

I just realized that in our ongoing debate of apples and oranges, we have delved into discussing how temperature is arbitrary but time is not. The last part of that argument because we have a standard definition for second, which is based on minutes, based on hours, based on days, based on earthly rotation and revolution. This is subdividing a finite period. The argument for every other scale involves looking at things without known bounds. While we have zero Kelvin (at least we have no proof that things get lower) we have no upper bound. For that reason, the "size" of the units is arbitrary (at some point I'm going to start spelling that correctly the first time). Likewise, distance has no upper limit on which to subdivide.

The argument that seconds are not arbitrary (I did it) consider earthly rotation and revolution to have extrinsic meaning.

The argument that other scales are more arbitrary than time seems to rely on holding those methods of measurement to the standard that there needs to be at least two finite bounds. A more fair argument would be to compare 0-100 Fahrenheit to March 10-18, 1943.

[stoppedcaring]

The argument that other scales are more arbitrary than time seems to rely on holding those methods of measurement to the standard that there needs to be at least two finite bounds. A more fair argument would be to compare 0-100 Fahrenheit to March 10-18, 1943.

Or to 1 CE - 2014 CE?

[Pfhorrest]

The meter has a historical definition just as non-arbitrary as the historical definition of the second, in that it's defined in terms of the planet we live on. The meter was originally one ten-millionth the surface distance between a pole of the Earth and its equator (or "a quarter of a meridian" to be more precise, but that's what that means).

[Mambrino]

(Sorry about derailing the discussion, but this is interesting. Never actually crunched the numbers.)

And while I did say "couple of hours", now that I'm actually thinking about it, I must backtrack a little: that would include breaks for drinks and showers (so a slight overestimation). While the whole occasion might take a couple of hours, continuously in the heat room maybe 20-30 min tops at time (caveat: that obviously depends on the temperature and stuff, probably much shorter if it's much over 100°C, maybe even longer if it's 70-80°C). And of course, the humidity of air and the ventilation count, too: the important bit is whether your body is able to manage its temperature by sweating.

If there's more than 1.8% humidity (16.6°C dew point), your body cannot even in theory cool itself by sweating at 100°C. With 0% humidity, that happens at 127°C.

I know the air is very dry in there, but don't know if it's that dry. I guess I still overestimate the time spent relative the the actual temperature; one isn't supposed to break any records sitting there anyway, so maybe I'm bullshitting. Or maybe the placement of thermometer counts even more than I've thought? Usually I've seen it placed about or slightly above where the head of average person sitting in a upright position would be, most people don't. The heat difference (relative to vertical position) is quite noticeable. ... I need to get a wet-bulb temperature meter and review some physics next time.

[gmalivuk]

It could be that dry (1.8%), because remember how relative humidity scales with temperature. As I said, that corresponds to a 16.6C dew point, which is not especially cold at all.

Wet-bulb temperature does go up quite quickly with humidity, though (in part because air at 100C can hold so much that each percent RH amounts to quite a lot of water, which explains why I was incredulous about spending even a few minutes in that heat. At just 5% humidity the wet-bulb temperature goes up to 44C.

[LaserGuy]

I just realized that in our ongoing debate of apples and oranges, we have delved into discussing how temperature is arbitrary but time is not. The last part of that argument because we have a standard definition for second, which is based on minutes, based on hours, based on days, based on earthly rotation and revolution. This is subdividing a finite period. The argument for every other scale involves looking at things without known bounds. While we have zero Kelvin (at least we have no proof that things get lower) we have no upper bound. For that reason, the "size" of the units is arbitrary (at some point I'm going to start spelling that correctly the first time). Likewise, distance has no upper limit on which to subdivide.

The argument that seconds are not arbitrary (I did it) consider earthly rotation and revolution to have extrinsic meaning.

The argument that other scales are more arbitrary than time seems to rely on holding those methods of measurement to the standard that there needs to be at least two finite bounds. A more fair argument would be to compare 0-100 Fahrenheit to March 10-18, 1943.

Well, Celsius is currently defined in terms of the triple point of water (0.01°C) and absolute zero (-273.15°C), so it is based on fixed physical phenomena in much the same way that time is.

[schapel]

The meter has a historical definition just as non-arbitrary as the historical definition of the second, in that it's defined in terms of the planet we live on. The meter was originally one ten-millionth the surface distance between a pole of the Earth and its equator (or "a quarter of a meridian" to be more precise, but that's what that means).

I think that a meter is still more arbitrary than a second. What difference would it make if a meter were 10% longer than it is? The Earth would no longer have a circumference of 40000 km, but so what?

If a second were 10% longer, how would the time of day work? Would we have to get up a different time every day? Would clocks need to skip directly from 9:36 pm to midnight? Actually, we could have 60 seconds in a minute, 36 minutes in an hour, and 36 hours in a day, but what if a second were 9.739% longer?

There's an importance to a second being 1/N of a day that a meter having 1/N of the circumference of the Earth does not. When the metric system was created, every other unit of measurement that had been around for hundreds or thousands of years was abandoned and replaced with something new, but not the second. These were a bunch of smart guys that debated all the important points for hours at a time. Did they miss something about the second actually being arbitary?

[gmalivuk]

The second isn't freely arbitrary, in that timekeeping is way more convenient if it's 1/N of a day where N has a lot of nice factors to divide up into other time periods. But it was still pure cultural inertia that kept N at 86,400 instead of the 100,000 that would make more sense from a metricization standpoint.

[schapel]

Yeah, I just coincidentally realized that the French tried to introduce decimal time. Still, I see that all proposals for other time systems are based on subdividing a day into equal-sized pieces of time, so that the standard unit of time will still be 1/N of a day. The only less arbitrary units of measurement than a second I can think of are equal to some fundamental physical constant of our universe, such as the units in natural units: the speed of light is 1 c, the charge of an electron is 1 e, and so on.

[Klear]

This discussion reminds me of this:

https://www.youtube.com/watch?v=ulIOrQasR18#t=73

[mathmannix]

It remound me of the SNL metric time sketch from the 70's, might have been first season. I couldn't find it online, though.

[Klear]

It remound me of the SNL metric time sketch from the 70's, might have been first season. I couldn't find it online, though.

I've found this, but couldn't find the video either: http://www.imdb.com/title/tt0694656/plotsummary?ref_=tt_ov_pl

Might be here, but it's blocked here so I wouldn't know.

[mathmannix]

It remound me of the SNL metric time sketch from the 70's, might have been first season. I couldn't find it online, though.

I've found this, but couldn't find the video either: http://www.imdb.com/title/tt0694656/plotsummary?ref_=tt_ov_pl

That looks like it... I remember a couple in their living room, probably John Belushi and Gilda Radner, talking about how they got so much done today since there are now 100 hours in each day. Absurdist humor at its best.

[Klear]

That looks like it... I remember a couple in their living room, probably John Belushi and Gilda Radner, talking about how they got so much done today since there are now 100 hours in each day. Absurdist humor at its best.

I'm happy enough with 28, I don't think I could handle more than that.

[gladiolas]

A second could be the time it takes for an object to fall one ten meters in a vacuum at Earth's equator.

[gmalivuk]

Where on Earth's equator? At what elevation? How can we define the second in terms of the meter when the meter is already defined in terms of the second?

[lookeratterofcartoons]

In photography, a reverse blink is called an 'exposure'.