Hacker News new | past | comments | ask | show | jobs | submit login
Pirates of the Caribbean (Metric Edition) (2017) (nist.gov)
121 points by nkurz 14 days ago | hide | past | favorite | 73 comments

You could maybe call it piracy if Britain was issuing the letters of marque after the fact or something, but it would seem to me this is "legit" privateering as they were at war with France at the time.

I'm probably splitting hairs though. The popular opinion has always been "it's privateering when we do it, it's piracy when they do it". One man's terrorist and all that.

Countries which use the metric system: Everyone except the US, Mynanmar and Liberia. And kind of the UK.

As someone who grew up in a metric country and moved to the UK it sure doesn't feel like we use it here, but officially we use it. It's just we don't actually use it most of the time. So teaching in schools and tertiary education is in metric (including word questions about people travelling in a car on the motorway at "the speed limit of 112km/h"[1]), scientific stuff is universally in metric[2] and temperature is in C[3]. People measure distance in imperial, but volumetric measures and weights have come around to being sensible with just a bit of grumbling from extreme stick-in-the-muds like Jacob Rees-Mogg who have made a career out of living like it's still the 19th century.

[1] Which is not a number you will ever see on a speed limit sign nor is the answer that will be given if you ask an actual driver what the motorway speed limit is. They will universally say 70mph.

[2] Because of course

[3] Because also of course. F might be the second-worst unit of measurement after perhaps only degrees Rankine.

> the second-worst unit of measurement after perhaps only degrees Rankine.

I see you haven't heard about Delisle scale yet? https://en.wikipedia.org/wiki/Delisle_scale

Oh my word.

F is better for use in human temperature comfort than C.

Nope, you’re just used to it. If you’re used to Celsius it’s basically no different…

F is 'human scale' in that 0-100 is basically the range a human can operate without having to take serious extra precautions. Of course that doesn't make it 'better' and I'm sure if we'd grown up using Kelvin we would find that easy and intuitive.

But your second sentence is entirely the point. Practically if you’re used to C then you know exactly what the habitable human range is, and Fahrenheit is meaningless to you (I literally have no intuition for it - I know that 32 is zero C and and 100 is around 40 C, so I know what that feels like, but I can’t imagine at all what any Fahrenheit temperature between that feels like without googling the conversion).

So 0-100 being ‘human scale’ is nothing but perhaps a bit of a fun novelty, the only thing that is important is either having or building the familiarity and intuition (which is mostly just from experience of everyday use).

You can't imagine what 50F feels like? Or 80F? Come on.

Fahrenheit is also more precise. 2 degree F above normal body temp is a fever. 2 degree C is a trip to the ER.

Nope, no idea. If I plug in in numbers, I get 10°C and 26+2/3°C, both of which I can imagine, but neither of the Fahrenheit values have any meaning for me.

You could make the same argument for 0-30C.

Perhaps even more so, since 1F is a meaningless level of precision for most activities.

C is much nicer for weather use because the transition behavior of water around 0 C is a significant factor to human comfort and preparation.

-20 to 40C isn't as nice as 0-100, but it's not terrible.

AFAIR 0-100 wasn't the goal anyway. 0F was just the lowest they could reach in a lab setting at the time. Then they chose to have 180 degrees between water freezing and boiling.

Which raises the question of what was the point of Celsius in the first place?

Fahrenheit had already existed for around 20 years when Celsius was proposed.

With units of distance, area, volume, and mass we commonly deal with a range of several orders of magnitude, and often need to subdivide larger values into equal smaller values.

Because of that immense range it makes a lot of sense to have names for specific multiples or fractions of some base unit.

The metric system made all those names derived units powers of 10 times the base unit, made those names all prefixes applied to the base unit, and used the same prefixes for length, area, volume, and mass.

That was a noticeable improvement over previous systems, where length, area, volume, and mass might use different multiples for their derived named units, the names might not be connected to the base unit, and the names were often only used with one kind of unit.

The only real problem with the metric system was that instead of defining the original meter as 10^-7 times the great circle distance from the equator to the North Pole, it should have been defined as some specific round integer multiple of some existing distance unit that was in common use and reasonably well defined.

But with temperature we almost never in ordinary life or business deal with a large range. We don't need names for specific multiples or fractions.

Fahrenheit's original reference points might not have been the best, but if you wanted to switch to basing on something else you can do that without changing the scale. Fahrenheit's original 0 point was the lowest temperature that could be achieved in the lab via a specific procedure. The other reference point was average human body temperature. On that scale water freezes at around 32℉.

If you wanted to instead have the freezing point of water as your base, you don't need to make a new scale that defines the 0 point as the freezing of water. Instead you can keep the degree size the same, and define the 0 point as 32 degrees below the freezing point of water. Similar for the upper reference point. Define it so that water boils at 212.

That gives you a scale that is defined based on freezing and boiling water (which is what Celsius used, although originally Celsius went the other way--water froze at 100 and boiled at 0--but that was pretty quickly swapped), but that still matches the thermometers that are already in use.

Same thing when later you realize that freezing and boiling point of water aren't the best reference points. We've moved on from freezing/boiling to using the triple point of water, then to the triple point of water with a specific isotropic composition, and now it is based on the Boltzmann constant and has nothing to do with water.

Each time, we set the values so that the resulting scale matches the new scale to within the limits of accuracy that we can measure at the time.

It doesn't really matter what the exact reasons behind the Celsius scale was, it happened hundreds of years ago... The fact is that basically every field of science has settled on it for scientific use, and almost every country has settled on it for everyday use.

C predictions tend to be exact numbers. F predictions are typically "50, low 50s, mid 50s, high 50s" (four per decade).

10 C degrees are 18 F degrees. So in this interval, C has ten points and F has 7.2 points.

So maybe F better suits the accuracy of predictions (i.e. significant digits -type stuff).

Viewed from a non-American perspective, you're just rounding when talking about temperatures Fahrenheit because the numbers are uncomfortably large to be used directly.

In the rest of the world, the weather forecast is "21 C", not "low 20s".

But setting your thermostat to 67 degrees vs. 70 degrees is a noticeable difference, which is where F becomes a better measure.

As is setting your thermostat to 19C vs 21C which is what those convert to rounded to the nearest degree celcius.

Not really. It's not like there are no decimals.

It’s a well written story but I’m not convinced the metric system would have been adopted by the US even in the absence of pirates.

By the story’s own account, they were going to Jefferson who had already unsuccessfully lobbied for the metric system, and when the instruments finally did make their way to the Secretary of State they were unconvincing.

That said, I am still glad to have read the story and formed the opinion.

"""Montserrat is a lot nicer when you're not being held for ransom by pirates. """

"""Despite his qualifications, Dombey lacked one important attribute: luck."""

I love the writing style. It's rare to hit that right balance of sarcasm and academia.

Interesting article.

“Pirates of the Caribbean: Dead Man’s Grave” would have been a better title.

As opposed to Living Man's Grave?

We've run out of titles that make sense a good decade ago.

I don't know. A prediction of mine that titles would degenerate to single generic nouns like Plane came true, but there's plenty left in the dictionary. Ship, I suppose, could be a Pirates of the Caribbean reboot?

So you have the film Tenet. If you wanted to make a version that ran the story in reverse, how would you name it ?

Well, if the sequel involves a scheme enacted by a male character on an artificial Central American waterway, do I have the title for you!



Yes, new movies should have their titles in Klingon.


Please don't take HN threads into cheap flamewars. Or any flamewars. We're trying for just the opposite here.


Then there's the sad case of the Mars Climate Orbiter:

1999: A disaster investigation board reports that NASA’s Mars Climate Orbiter burned up in the Martian atmosphere because engineers failed to convert units from English to metric. Mars Photo Galleries: Where Will Next Mars Rover Land? Exotic New Mars Images From Orbiting Telephoto Studio Strange Places on Mars: What Do You Want to See Next? […]


There are two types of countries: ones that use metric system, and ones that landed a Man on the moon using the metric system...

NASA uses the metric system.

The official US foot has been based on a metric measure for more than a century now though:

    The Mendenhall Order marked a decision to change the fundamental standards of length and mass of the United States from the customary standards based on those of England to metric standards.

    It was issued on April 5, 1893, by Thomas Corwin Mendenhall, superintendent of the United States Coast and Geodetic Survey, with the approval of the United States Secretary of the Treasury, John Griffin Carlisle.
At this point every US unit of measure (length, mass, volume, temp, second, etc) is defined in terms of a metric fundemental.

The US public are really just pretending that they don't use metric.

NIST and NASA don't pretend, they're metric to the core and just slap on some funny feet for the common pleb.

> The US public are really just pretending that they don't use metric.

That’s a silly thing to say when this whole thread is complaining about how Americans don’t use metric. We’re not pretending—we really don’t use it.

I myself am quite a fan of the metric system—unusually so for an American. I use it wherever I can intuit it, but that’s very hard when you’ve lived and continue to live in a culture that (despite your weird pedantic statement) doesn’t meaningfully use it outside of the sciences. Which is a shame, because I’m extremely jealous of that 1:√2 paper ratio.

Meters aren’t so bad to get used to; a meter is about a yard (0.91 m) and a kilometer is about ten football fields (1.10 km). But the major streets in my city are all a mile‐wide [super‐]block apart, so kilometers are too inconvenient to describe my routes. Liters are easy, since every American knows the size of a two‐liter soda bottle. But despite knowing the boiling/freezing points of water in both systems (212 °F/32 °F maps to 100 °C/0 °C), and keeping the thermometer in my car on Celsius for many years, I still don’t have an intuitive grasp of temperature in metric; without calculation, I can’t express the temperature outside in Celsius, nor when given a temperature in Celsius do I have more than a vague sense of how hot or cold it is. And kilograms are right out.

That’s what it’s like for someone who’s trying. Most Americans never experience metric in common measures past the 30 cm rulers they use in grade school (which always get flipped to the inch side).

> without calculation, I can’t express the temperature outside in Celsius

I think you'd get used to it rather quickly if it becomes ubiquitous in your daily life. It's probably a little bit similar to when there's a change in currency or some such - like when the EU introduced the Euro. Someone here could maybe confirm from personal experience but my German and other EU friends all mentioned that in the first few weeks it was quite the headache, "is this price expensive or not", but after a while the numbers start to stick and make sense of their own.

Other countries, that joined the eurozone later, had months of both currencies listed to help get used to. Sure, though, getting used to another currency (was) is not hard.

I'm Antipodean and grew up on metric but can do all the imperial measurements. Both the US and UK like to not use metric (or some hybrid).

Kilograms are pretty easy. 1 L of water is 1 kg. 1 pound is 0.4536 kg but it's usually easiest to just use 0.5kg for a rough estimate and that makes it 2 pound to 1 kg. If more precision is needed then a calculator is never far away.

For temperature:

-20° is dead (it's not really, but Australians tend to feel this way), I believe this temperature can be dangerous without adequate protection -10° is Australia also doesn't really get this temperature 0° is jacket temperature, and freezing water, although the freezer is usually at -3-5° (I think) 2-3° is the fridge temperature 10° is jumper temperature 20° is roughly t-shirt temperature 22-23° is a nice comfortable temperature 25° start of a heatwave in the UK and NZ, still cool for Australia. 30° is not nice temperature unless you have a pool or aircon handy. 40° is "what are you doing moving around" temperature. Find aircon or swimming pool urgently. 45-47° is "you shouldn't have gone out to the desert" temperature.

Like imperial to metric this definitely also comes out with currency conversion. Having travelled a lot, the first few weeks are definitely the hardest, then it starts to become intuitive.

The GBP to AUD is fairly easy because it's roughly 2 AUD to 1 GBP. Things like Norway/Sweden/Denmark are harder because it's 6.90, 7.50, 4.50, these tend to just be rounded to 5 and 10, which is generally close enough to not make stupid mistakes. Things like Hungarian Forint are a bit harder again 1.00 Australian Dollar = 231.49064 Hungarian Forints, But again it's just rounding to 200 and then establishing thresholds. 10 is 2000, 50 is 10000, 100 is 20000, 1000 is 200000.

And I went down a rabbithole :)

I got used to it faster than I thought I would, just setting my phone to show me metric all the time really helps.

20C is room temp. 10C is chilly. 0C is cold, anything below -20C is dangerously cold. 30C is hot. 37C is body temp, anything above 40C is dangerous, 50C is summer in Arizona hot.

> 37C is body temp,

37 is considered slight fever. 36 is more like it

Quoting Wikipedia, the normal human body temperature range is typically stated as 36.5–37.5 °C (97.7–99.5 °F)

37 is the usual round number given for the body temperature, not 36.

>37 is the usual round number given for the body temperature, not 36.

I don't know which country/region that might be, if you look at a picture of hg thermometer - 37 would be marked red (which doesn't make it precise, of course). Young children do have higher body temperature. There is even pharmacy chain 36.6, pretty much any rounding I have ever heard - 36C.

As for quotes, here is another:

Most people probably grew up being told a body’s normal temperature was 98.6 degrees Fahrenheit (or 37 degrees Celsius). That widely accepted number originated from a study done in the mid-1800s. But newer studies suggest the average person today actually runs a little cooler than that — somewhere between 97.5 F (36.4 C) and 97.9 F (36.6 C). [0]

[0]: https://health.clevelandclinic.org/body-temperature-what-is-...

> We’re not pretending—we really don’t use it.

Of course you are you simply don't realise it.

The US foot isn't based on Washington's forearm length or anything uniquely USofA - it's literally and officially defined in terms of the meter as a fundemental unit and it's been that way for more than a century.

When you get an official US foot as a reference (for precision machining) then you get a specific metric length.

I don’t think this is a great argument: every useful unit system in the physical world can be converted to equivalent units in the same dimension.

Congress could redefine the imperial system in terms of something stupid tomorrow (like a particular bald eagle’s wingspan), but it wouldn’t be correct to say that Americans are using the “bald eagle system”: they’re measuring things the same way they were the day before.

I mean even metric is somewhat defined by the world 0°C is the freezing point of fresh water 100° is the boiling point. That's somewhat arbitrary. You could as easily have used saltwater as °F does, the difference in this case is that it's divisible in 10s 100s.

The original definition of a kilogram is 1 litre of fresh water (I think they're more precise now), but it still works for common usage.

A litre is 10cm x 10cm by 10cm of water (it's metric turtles all the way down)

Finally the original definition is where we get to the base arbitrary, it was 1/10,000,000 of the equator to the north pole (it has since evolved, from the 1790s).

What's important here is the consistency and ease of use in mathmatical units with everything being in 10s and 100s.

> Of course you are you simply don't realise it.

Don’t be ridiculous. Of course I know that the customary units are formally defined in terms of metric. I also know my milk jug, like all gallon milk jugs in America, says “3.76 L” next to “1 gal” on the label. But if I ask someone—anyone—in my family or my workplace to pick up three liters of milk, they won’t have any idea what I mean. If that’s your idea of a culture that “uses” the metric system, you have a very strange definition of the word “use.”

>nor when given a temperature in Celsius do I have more than a vague sense of how hot or cold it is

As an electrical engineer don't you deal with temperature? Pretty much all datasheets are in C.

About temps - I can convert them in my head w/o much an issue (c=5/9 * (f-32); normally I need to convert F to C only), however something as reference point: F scale was designed as 0 - freezing point brine (salt water), 100F - body temperature; the thermometers were bit off, as 100F is a slight fever (37.7). Normal human body temperature is ~36C.

My point is that 100C (boiling point) is not very useful for a person using F as a reference point when/why something feels hot or cold. 50C is already too hot and causes burns.

> As an electrical engineer don't you deal with temperature?

Sure, but I’m talking about in the context of everyday life, shooting the breeze, and all that.

> My point is that 100C (boiling point) is not very useful for a person using F as a reference point when/why something feels hot or cold.

Indeed, the mnemonic I actually use in practice is “32 °F is 0 °C; 32 °C is a really hot day.” Sadly, I still have to do the math for anything in between!

Reminds me one of the (not funny) jokes form the '80, IQ not reaches the room temperature. This shizz is virtually not-translatable (20 IQ, c'mon), however it's quite representative for the unit mix-up in US fashion, e.g. weight and force being the same unit, volume for solids (cups), hip/valley in inches (instead of degrees, on a speed square).

Overall the imperial system is quite different, in non-engineering setup, and its applications are also non-intuitive for metric users - I suppose the reverse is pretty much the same.

But that’s just cosmetics. The system itself is defined in metric.

Btw a kilogram is about 2lbs. And funnily in europe we would often order “half a kilo of X” when buying groceries.

In France, we can ask for "une livre de beurre" which directly translates to "a pound of butter" which has been standardized to 500g (half a kilogram). So yay! You can use one freedom unit in France ;)

*and the ones that landed a Man on the moon using the metric system.

And crashed a probe into Mars because someone in the chain didn't use the metric system.

>Although data was stored internally in metric units, they were displayed as United States customary units.


This conversion is cognitive load for the engineers, who eventually made a mistake with the mars climate orbiter. Now NASA uses metric exclusively.

Indeed. Freedom units are objectively inferior in every way and I'm glad NASA pilots finally got on board.

I struggle to believe some space agency ever used the imperial system (or the US spinoff) for anything mission critical.

...well NASA (or its supplier) did try - the infamous Mars Orbiter crash[0]:

The primary cause of this discrepancy was that one piece of ground software supplied by Lockheed Martin produced results in a United States customary unit, contrary to its Software Interface Specification (SIS), while a second system, supplied by NASA, expected those results to be in SI units, in accordance with the SIS.

[0]: https://en.wikipedia.org/wiki/Mars_Climate_Orbiter#Cause_of_...

> According to NASA, the cost of the mission was $327.6 million

It probably makes the top 10 most expensive software defects of all time.

Microsoft Windows was likely #1.

Maybe not NASA, but what about its contractors? https://www.simscale.com/blog/nasa-mars-climate-orbiter-metr...

The gauges in the Apollo modules were all in US customary for the benefit of the pilots. AFAIK the underlying systems used metric internally, though.

Sounds like you don’t know much about the history of the United States space program.

Applications are open for YC Winter 2024

Guidelines | FAQ | Lists | API | Security | Legal | Apply to YC | Contact