This is because Kelvin, like meters/miles, are already a measurement of some physical feature, in this case of kinetic energy of the particles.

The word "degrees", on the other hand, does not represent a meaningful measurement of anything. It just means a given part of some arbitrary whole, defined by convention.

e.g. the "whole" of an angular degree is just a single complete rotation. The "whole" of a Celsius degree, I believe is the range that goes between water freezing (0°C) and boiling (100°C) points, and that's why it was also known as the centigrade scale.

Extra curiosity: still as of nowadays, if you say the complete temperature unit in Spanish, you don't say "35 degrees Celsius", you say "35 centigrade degrees" (35 grados centígrados). At least in a colloquial context; not sure how they'd say it in a science-related professional environment.

On a side note, it would be awesome if all temperatures were in Kelvins.

> On a side note, it would be awesome if all temperatures were in Kelvins

You have my unconditional vote on that one! :-D

It would be cool if compass was inertial.

This approach reminds me of the works of a different person - Edward Tufte. He writes about visualizing information, but that by itself is a user interface (even if we didn't call it this until recently). He gives plenty of praise to designs like this - which show you everything at once, and play into strengths of your visual system, which is very good at focusing, zooming out, filtering out things you're not interested in, and switching focus rapidly.

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.

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.

If you really want to hit an exact number, you can add a query string to the URL.

https://degreeswhat.com/?-40

https://www.theverge.com/tldr/2021/7/13/22575368/apple-ios-1...

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.

- Celsius or Fahrenheit?

- Yes

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?

Not for force, no, but: https://en.wikipedia.org/wiki/Newton_scale

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.

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.

It's how these things go. You and me think of "temperature" as something simple, like it all started. You know, you find some material that noticeably expands or contracts when warmed or cooled, you turn it into an indicator along what will be a scale, and you make a mark for e.g. "roughly when water starts freezing over" and "when water starts boiling"[0]. You make a regular gradation in between, let it spill over below and above your "min" and "max" anchors, you put some numbers on this, and "Bob's your uncle".

This of course is super useful, so others refine your "thermometer", as they realize just how stable and broadly-applicable this "temperature" is as a measure. Eventually some start asking how it all works, and you hear some grumbling about average kinetic energy of particles, which still kinda makes sense. I mean, lots of tiny things buzzing around, and there's that German guy saying you can't possibly measure each of the tiny things individually, but whatever - the average, low-frequency part is stable.

But then those theorists push and push, and break through the barriers of sanity. They enter R'lyeh and start transcribing the Eldritch tablets found inside. Suddenly, you see temperature redefined using something else, something you recall should also be a statistical phenomenon but suddenly isn't[1]. You see words like entropy and enthalpy thrown around, and then some American mathematicians get involved, and suddenly there's also negtropy and fractional bits, and nothing makes any kind of sense anymore - temperatures going below absolute zero, the "nothing actually moves anymore" point, leading to negative temperatures where heat flows from colder to hotter...

...really that's one of the least weird thing in hard sciences these days.

--

[0] - In the process discovering that this was a really good choice of anchors, as water behaves in strange ways at exactly those two temperatures.

[1] - Or is it? Are you sure what "statistical" means these days? Are you sure what "means" means these days?

https://en.wikipedia.org/wiki/Negative_temperature

Wait what?!! That feeds my daily “oh oooh” moment.

Basically, coldness is 1/temperature but makes more theoretical sense:

> Though completely equivalent in conceptual content to temperature, β is generally considered a more fundamental quantity than temperature owing to the phenomenon of negative temperature, in which β is continuous as it crosses zero whereas T has a singularity.[6]

> In addition, β has the advantage of being easier to understand causally: If a small amount of heat is added to a system, β is the increase in entropy divided by the increase in heat. Temperature is difficult to interpret in the same sense, as it is not possible to "Add entropy" to a system except indirectly, by modifying other quantities such as temperature, volume, or number of particles.

--

[0] - https://en.wikipedia.org/wiki/Sundiver

[1] https://en.wikipedia.org/wiki/Laser_cooling

But we tend not to talk about the 'temperature' of electron energy levels. If we did, then they would have negative temperature.

That's a common simplification, but not really the definition. At the minimum, quantum mechanical effects make this complicated.

But you are right in a sense. From Wikipedia:

> The absolute temperature (Kelvin) scale can be understood loosely as a measure of average kinetic energy. Usually, system temperatures are positive. However, in particular isolated systems, the temperature defined in terms of Boltzmann's entropy can become negative.

Well, the simpler solution would have been to just use radians ;)

Also sorry to be that guy but:

> when people specify a temperature in "degrees" when it’s not clear from the context which scale is being used.

It should be degrees Celsius. Anything else is just insane ;)

I'm not saying it makes a ton of sense, but my only real defense of it.

That said, I find negative units rather silly in most measurements, so we should really be using K I think.

That's your choice though. Outside temperature cannot be measured precisely enough to warrant decimals (it's supposed to be 17.4°C outside but who can tell the difference with 17°C or 18°C...) but my car's A/C is set to 21.5°C and my home's heating is set to 19.5°C.

Ovens aren't accurate enough for measuring 5°C, let alone 2.5°C.

(Ignoring badly-translated American recipes which call for 179°C and 454.5g of potatoes.)

For air temperature, my behaviour wouldn't change at all if someone told me it is 18±0.25°C rather than the normal 18±0.5°C. We could round to the nearest 2° and it would be fine.

> badly-translated American recipes which call for 179°C and 454.5g of potatoes

This drives me up the wall .. but a lot of UK goods are sold in "metric-numbered imperial sizes". At the weekend I bought 450g (half lb) of meat and a 6.3mm (1/4") router bit.

Measuring body temperature with precision of 0.1°C is very common. In fact, I never saw an integer in this context.

Measuring by weight is the one cooking-related hill that I will die on.

(Recently, I had a recipe ask for four cups of lettuce, which could've been anything from 0.5x to 4x of what I finally went with, depending on how much I packed the cups. It's lunacy)

No argument from me about Celsius, but even on this site there are people who think otherwise.

Celsius is obviously more useful in a scientific context, but 99% of the time when I'm talking about the temperature, I'm not doing a scientific experiment, I'm asking "how hot/cold is it outside?" In that context I actually find Fahrenheit to be a more intuitively useful scale once you get used to it.

Celsius crams the entire range of likely outdoor temperatures into a narrow range with awkwardly-sized units that don't provide enough information. If someone tells me it's 15C outside, how many layers do I need to wear? I still don't have a good feel for it from the number alone, even after spending most of my life in countries where Celsius is the norm.

But in Fahrenheit, things make more obvious sense. 0 F means "insufferably cold", 100 F means "insufferably hot", and to get a meaningful idea of what the weather feels like on my skin, I just need the range: it's "in in fifties" or "in the seventies" etc.. It takes some getting used to, but I actually quite like it. Thanks, America!

(I'd also make a similar argument that feet and inches are a much more intuitively meaningful scale than centimetres for measuring human height. But that might be my British bias.)

It begins with something like "I decided to create the perfect scale for measuring the temperature outside for the weather. Of temperatures taken where people live, I will scale the 95th percentile of high temperatures as 100 and the 95th of cold temperatures as 0."

The goal of which was, if a temperature is <0 it's really cold, and a temperature >100 is really hot.

My memory is that using this method the scale was within 2 degrees of Fahrenheit! Of course, I've never found the story again so who knows the details of their method or if I'm even remembering correctly.

Erm, they didn't invent it. Most (all?) American units were inherited from British. Farenheit was invented in Europe.

I have also warmed to Imperial/American units for certain things. A lot of simple recipes are easier to remember in ounces than in grams. For example, 5 ounces of flour and 4 ounces of butter gives you enough shortcrust pastry for a 9 inch tin. Inches seem about the right size, but centimeters are too small. People's heights tend to fall around 5-6 feet which is nice, or 150-180/1.5-1.8 which is kind of awkward. Basically, imperial measurements seem much more "human" while metric seems based on arbitrary universal constants like the speed of light which have absolutely no bearing on our lives.

None of this means that "cups" are a sane way to measure ingredients for cooking, though. There's just so many reasons why it's bad but even just from a laziness point of view it's an extra thing to wash up.

Um, No. Metric is based on the size of the Earth and the density of water.

The original definition of the meter was "one ten-millionth of the distance from the pole to the equator", making the circumference of the Earth 40,000 km or 40 Mm. The kilogram was originally defined as the mass of one litre of water. (1 m³ = 1000 kg). It wasn't arbitrary.

Basing a unit of measurement on the size of the Earth? Why not base it on the size of the Sun, or on the distance between Toronto and Timbuktu, or on the combined height of every member of the U.S congress if they all laid head to toe? Those numbers mean nothing to me, but I have a good intuitive feel for distances like "the general range of human heights", "the size of my foot", or "how far I can walk in an hour". Imperial measurements have their origins in those kind of intuitive, everyday quantities that we humans have a natural feel for; that's the sense in which they're not "arbitrary".

That doesn't nmake imperial measurements unconditionally "better", it just makes them more useful and relatable in certain contexts.

I also find inches, feet, miles etc. more intuitive than meters for basically everything. "so-and-so meters" or "such-and-such kilometers" doesn't describe anything to me, give it to me in inches/feet/miles so I can visualize the damn thing.

Moral I suppose is that metric is great for describing the universe, but the problem is we're dumb apes.

For the kinds of maps I coded for in the 1980's you'll want your compass rose to indicate

* Geographic North (on, say a WGS84 ellipsoid)

* Magnetic North (where a magnetic compass points, this varies by time and geographic location)

* Rotational North (the spin axis of the planet - it walks a bit)

This things can be added if you're looking for an additional ( pointless? ) challenge.

There's "real life navigation" - these things matter at high and low latitudes, and near massive iron deposits such as Kursk, not so much elsewhere - although orienteering with magnetic compass only requires understanding of local deviations.

There's also "teaching geodesy" - which might allow you to simulate changes of location etc.

All of this, of course, goes beyond a simple exercise in inferface design and angles.

I threw it in there in case you're looking for further coding exercises.

I guess the remaining question is .. analog clock directions? Does the most recent generation need to be reminded to watch their six o'clock?

[*] https://en.wikipedia.org/wiki/Kursk_Magnetic_Anomaly

Honestly, I just thought it would be an amusing way to convert temperature, and a subtle dig at people who don't use the correct units. I don't want people to use this as an actual compass, and get themselves lost because of it.

> I don't want people to use this as an actual compass

Hence the educational route option should you so choose.

Of course anybody running this on a mobile device will have full GPS and maps available.

Learning about reality is for those that want to navigate by actual compass and|or stars.

So you were concerned that people might get confused, yet you choose to mix angular and temperature degrees in the same interface?

An odd choice. I thought causing maximum confusion was the goal. (In a fun way, admitadly.)

On Google maps this is supposed to use the magnetometer to point the arrow in the correct direction, but it never works and nor does the stupid calibration phone-waving thing it asks you to do.

On my device the arrow points in approximately the correct orientation. (Plus minus ten-ish degrees.) If yours never work even to that level, even when you are away from magnetic sources then probably your device is faulty. (Do make sure you don’t have body worn magnets, or magnets in the phone case/holder of course.)

If it works to the same approximation, but you are expecting it to be more accurate then you should choose a different tool for the job.

The link https://degreeswhat.com/?100 too quickly tracks the mouse and you lose the pointer to the specific degrees

Unfortunately your compass bearings seems a bit off.

1. Compass degrees go 0 to 360

2. North is traditionally at the top

Yours only has half the compass (East) and seems to be reversed or mirrored

Edit: direct linking works https://degreeswhat.com/?270 and I get the correct bearing (270 = West), I think it is still mirrored for a compass because you increase from 0 anticlockwise.

It's actually more like 15.0411° in an hour. This matters if you're keeping a telescope pointed at something in the night sky to take a picture of it.

6: degrees of separation, at most, between any two people.

Also, USA murder degrees: first, second, third.

Another thing: the melting point of 60/40 solder is there; but not the eutectic mixture 63/37. Geeeeez!

If anyone has interesting temperatures or angles to add, please do!

Is the description accurate? How to display Kelvin units or other scales?

Fahrenheit temperature degrees are based on concepts of angular degrees (just as Centigrade is based on concepts of slope).

Many people know the Fahrenheit temperature scale is based in part on the coldest fixed temperature readily available to a scientist in the 1700's, namely the coldest temperature achievable when water ice is placed in a salt water bath (which he called 0 degrees).

Because choosing this fixed point meant Fahrenheit was basing his temperature scale on water, he viewed the coldest pure water temperature (ice) and the hottest pure water temperature (boiling) as significant in that they were, in his mind, opposite "directions" for water.

In his mind, frozen water and boiling water were therefore 180 degrees apart from each other.

Why did water ice and boiling water get these crazy 32 degree and 212 degree temperatures? The Fahrenheit scale is based on two constraints, not one.

The first, as is commonly known, is optimally salted ice water should be zero degrees.

The second constraint is that frozen water and boiling water should be 180 degrees apart.

212 degrees - 32 degrees = 180 degrees. If you constrain the temperature of salted ice to 0 and constrain the temperatures of frozen and boiling water to differ by 180, you get the fixed points of 32 and 212.

When Celsius invented the temperature scale we call centigrade, he used very similar constraints and also used angular thinking.

Both scales consider the freezing and boiling points of pure water to be significant.

The Celsius scale uses the freezing point of water as its zero, the Fahrenheit scale does not.

The Fahrenheit scale uses 180 degree based angular thinking to describe the transition from ice to steam, hence T(boiling) - T(ice) = 180.

The Celsius scale uses surveyor's percentage slope terminology (where a "grade", as in centigrade, of 100 corresponds to rise = 100% of run, or 45 degrees in angular terms), so T(boiling) - T(ice) = 100.

This page would be a wonderful vehicle for showing these connections (and the ice equals about 30 degrees and human body temperature equals about 90 degrees coincidences that Fahrenheit the numerologist found so compelling).

I hope the creator tweaks their page to show the actual angular history and relevance of these temperature scales. There is quite a bit of history of science in these relationships, all with the advantage of being readily accessible to a bright grammar school kid, which is a great age to stoke the fires of interest in science.

Could the compass get the magnetic heading from the browser on mobile?

Yes, possibly. There's a webkit extension but I'm not sure how well it's supported. I'll look into it.

I use tau in the code actually. JS trig functions use radians, and SVG uses degrees; when I convert I use tau instead of pi.