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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? […]
https://www.wired.com/2010/11/1110mars-climate-observer-repo...
NASA uses the metric system.
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.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.
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).
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.
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 :)
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.
37 is considered slight fever. 36 is more like it
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-...
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.
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.
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.
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.”
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.
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!
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.
Btw a kilogram is about 2lbs. And funnily in europe we would often order “half a kilo of X” when buying groceries.
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_...
It probably makes the top 10 most expensive software defects of all time.