5 ms·
I always want to ask “degrees what?" I once worked on a system that ran at -40 degrees. I loved leaving off the scale when giving tours and telling about it,
by mdturnerphys 3y ago
I always want to ask “degrees what?"
I once worked on a system that ran at -40 degrees. I loved leaving off the scale when giving tours and telling about it, because someone would invariably ask if I meant Celsius or Fahrenheit and then everyone got to learn where the crossing point of the two scales is.
- lostmsu 3y ago-40K are impossible AFAIK
- a2800276 3y agoThat's why they say it's -40 degrees. :P
- Lester_Square 3y agoKelvin is not measured in degrees however, so is excluded by implication
- flangola7 3y agoIt's not? What is it measured in then?
- bmicraft 3y agoK, not °K
- unwind 3y agoIt is simply measured in Kelvin. Kelvin is the standard unit for temperature, 0 Kelvin is the absolute zero point. Each step is the same size as a degree Celsius, but there are no "degrees". Edit: remove assertion that the scale does not go into negative, because physics.
- deelly 3y agoAs a non-native reader, I`m not sure that I understand. Could you explain why 100 Kelvin, but 100 degrees Celsius and 100 degrees Fahrenheit? Is there some special meaning in a word "degrees" there?
- forbiddenlake 3y agoEarlier comment - https://news.ycombinator.com/item?id=36584908 https://news.ycombinator.com/item?id=36584908
- arrowsmith 3y agoWait, so it's just "five Kelvin", not "five degrees Kelvin"? TIL. Now that I think about, what's the etymological reason we use "degrees" to talk about temperature? We don't measure force in "degrees Newton" or electric current in "degrees Ampère". Why do we do it for Celsius and Fahrenheit?
- Y_Y 3y agoFive kelvins. Just like five metres, no capital letters or funny symbols. The reason you can do it for Celsius or Fahrenheit is that those are scales but not units. The energy in two bodies (with constant heat capacity) at 100° is not the same as in a single body at 200°, but if you use kelvins then it works out.
- ben_w 3y ago> We don't measure force in "degrees Newton" Not for force, no, but: https://en.wikipedia.org/wiki/Newton_scale https://en.wikipedia.org/wiki/Newton_scale
- evanb 3y agoI don’t know but freezing and boiling of water are separated by 180 degrees F.
- onion2k 3y agoYou can go below absolute zero, but things get weird. https://www.sciencedaily.com/releases/2013/01/130104143516.htm https://www.sciencedaily.com/releases/2013/01/130104143516.h...
- cinntaile 3y agoThat seems to be taking a theoretical approach. I don't think there are any experiments that have proven it is possible?
- xen0 3y agoPopulation inversion is a thing; many lasers exhibit this behaviour. But we tend not to talk about the 'temperature' of electron energy levels. If we did, then they would have negative temperature.
- Y_Y 3y agoNegative temperature is a perfectly normal and well-studied phenomenon with lots of common examples. Temperature is defined as the rate of change of entropy wrt internal energy, usually more energy means more entropy, but it's not a given. https://en.wikipedia.org/wiki/Negative_temperature https://en.wikipedia.org/wiki/Negative_temperature
- deleted 3y ago[deleted]
- aziaziazi 3y ago> A system with a truly negative temperature on the Kelvin scale is hotter than any system with a positive temperature. If a negative-temperature system and a positive-temperature system come in contact, heat will flow from the negative- to the positive-temperature system Wait what?!! That feeds my daily “oh oooh” moment.
- Y_Y 3y agoEnergy flow wants to maximize entropy. Usually things flow from hot to cold because a cold thing will "make better use" of the energy to create entropy (i.e. permit microstates). Something with negative temperature will increase entropy by losing energy, and the positive temperature thing will increase entropy by gaining it, so it's (thermodynamically) a no-brainer.
- RheingoldRiver 3y agoWhen I was taking algebra 1 in middle school I learned that all non-parallel lines had to intersect and this made me realize that the temperature scales must intersect, so I calculated their intersection point. I thought it was the single greatest discovery anyone had ever made and told literally every adult in my life about it. -40 C/F has always held a very special place in my heart haha
- diego_sandoval 3y ago- Minus 40 degrees - Celsius or Fahrenheit? - Yes
- j1elo 3y agoFunnily enough, the scale on the linked page doesn't allow me to set -40°. It jumps between -39.9 and -40.1 So seems like -40.0 is really where the singularity lies. Either that, or a simple rounding issue. I choose to believe it's the former.
- imglorp 3y agoRemember that time when it was a rounding error? https://www.theverge.com/tldr/2021/7/13/22575368/apple-ios-14-weather-app-69-rounding-error https://www.theverge.com/tldr/2021/7/13/22575368/apple-ios-1...
- perilunar 3y agoNot a rounding error in this case, but more to do with the precision of your input device and your screen size. The input angle and the converted temperatures are rounded to the nearest 0.1 degrees, but it is possible to hit 40.0° (I should probably add an option to round to whole degrees.) If you really want to hit an exact number, you can add a query string to the URL. https://degreeswhat.com/?-40 https://degreeswhat.com/?-40
- joshspankit 3y agoIf you’re using a touch display, it’s easier to land on specific numbers by moving your finger away from the centre. The further your finger, the finer the adjustment.
- foobarbecue 3y agoYeah. When I worked in Antarctica this was often the temperature and it was quite convenient.
- hanche 3y agoThat’s how I convert between Celsius and Fahrenheit, if I have to do it in my head: Add 40, multiply by 9/5 or 5/9 depending on what direction, subtract 40. Easily remembered!
- tzs 3y agoFor some reason that reminded me of a Futurama joke, although I'm not sure why since it is completely different. LEELA: Fry, night lasts two weeks on the moon. MOON FARMER: Yup. Drops down to -173. FRY: Fahrenheit or Celsius? MOON FARMER: First one, then the other.