most needs for such water are for calibration of instruments - many labs run stable isotopes measurements which has many applications from tracing how plants use water to measuring your metabolic base rate .. so the main use case it to calibrate instruments because it's really difficult to have an absolute measurement of stable isotope ratios from first principles - and the ratios are so small you typically express them in relation to standards like VSMOW
For more context, sample reference materials from the NIST reference catalogue are not meant to be exceptionally high purity examples of the sample -- SRMs are usually commercially-produced products. The real value is that each sample comes with a datasheet with incredibly detailed and accurate measurements that are (as you said) used for calibration of measuring devices in industrial settings. To quote a Veritasium video about the topic from a few years ago[1], "the thing you're paying for is not the peanut butter, it's the knowledge of exactly what is in the peanut butter".
Truth. I once paid nearly $500 for a set of 17 certified, calibrated wooden pencils, with documentation showing that each one met their rated hardness levels of 9H thru 6B. And for $500, they don't even come with erasers, that is an added-cost option.
I'd like to ask a more specific question than my sibling's excellent "Wait, why?" question :)
Why offer erasers on these things? The procedure described below has nothing to do with using these as pencils, and at $500 for a pack I can't imagine anyone, anywhere casually drawing with these.
(Is there another procedure, similar to the one described below, except instead of dragging the pencil tip across a surface you drag the eraser across it? )
You use the kit to test the harness of a finish coating, like a paint or a ceramic coating for cars. Pencils have their own hardness scale which can be used to gauge the hardness of the coating. Its really more of a relative qualitative test than quantitative as you'd use this for sample/coupon testing identical coatings. There are more absolute, quantitative methods to measure various hardness characteristics (scratch, indentation, and rebound). Like you'd use the pencil kit on a factory floor to make sure each paint sample performs the same, the sample being a small area on the product or a plate that's painted the same way.
His link includes procedures, which suggest he was testing the hardness of some surface coating or similar:
> For the pencil hardness test, reference ASTM D3363, pencils of increasing hardness values are moved over the surface in a precisely defined way until one lead damages the surface. Surface Hardness is defined by the hardest pencil grade which just fails to damage the surface.
> Observe the pencil track. Sufficient pressure must have been applied either to cut or damage the coating or to crush the lead pencil point.
> If neither coating damage or pencil point crushing is observed, repeat the test until a definite observation is made.
> If scratching or damage of the surface occurs, proceed with the next softer pencil grade and repeat the testing process until a pencil lead grade is found which crushes and does not damage the coating.
> If crushing of the hardest lead should occur, the coating is therefore extremely hard and is beyond the measuring range of this test
That’s $508 for two cartons for 400 cigarettes total, so $1.27 per cigarette. They’re not characterized like the peanut butter, they’re just manufactured to a specific QC standard.
California/New York prices are easily $0.75/cigg so it’s not that much more expensive.
I had seen the cigarette. But but not the meat which costs $2,690 for four tuna-can size cans and is a mix of pork and chicken
Thinking of a concept for a restaurant meal along the lines of a calibrated fried spam dinner, that costs ~2k for about a can worth, fried like they do in Hawaii.
Come to think of it, would love to see an “iron chef- calibrated foods” edition.
Yes, it’s a bit frightening to know what a hidden dependency NIST is on many things. In my industry, all calibrations ultimately derive from physical NIST standards for resistance, frequency, etc.
I suspect the fear comes from both seeing NIST as a single point of critical failure, and perhaps also that it is a far less resilient and/or far more vulnerable, institution than may have been previously realized.
Interesting article but left me wondering why they don't use ¹H₂¹⁶O as the "standard water"? Surely you can make that (relatively) easily in a centrifuge by spinning out the lightest fraction of water.
18 O enriched water is available to buy but the pricing suggests it's quite expensive to separate 16 O from 18 O. And you get much less variability in the ratio of isotopes from mixing compared to separating a single isotope as much as possible.
Unless you're actually measuring something with any importance, a gallon is about 4 liters. More closely 3.78541... But saying a quart and a liter are about equal is often good enough.
You can centrifuge it. Heavier molecules move closer to the bottom. Repeat until you reach the desired purity.
You need shitloads of ordinary water to extract a liter of heavy water. And I'd be surprised if there's any superheavy water in that, because tritium radioactively decays.
Fun fact: Heavy water is slightly toxic to humans. If you only drank heavy water, you'd die as it shifts the chemical reactions in your body out of balance. A moderate amount is fine though.
IIR, a number of rich & famous people have developed severe mercury poisoning after extended conspicuous consumption of swordfish and other very expensive/very contaminated seafood.
Obviously the luxury bottled water industry is missing out on the potential of D2O and T2O.
This is why we should ditch Celsius for Kelvin. I never liked how we coupled 0 and 100 to where water freezes and boils under certain conditions. Kelvin doesn't rely on non-invariant reference points.
this is actually why i like fahrenheit the most... 0F is "really cold" and 100F is "really hot", whereas in celsius 0C is "kind of cold" and 100C is "uninhabitable". it makes sense for the 0-100 range to be reserved for temperatures frequently encountered in our habitat as humans i think...
That’s a biased view that leads to a scale only convenient for people living in particular latitudes. Now talk to someone living near the equator like Singapore, and 0F is unimaginably cold (even 40F is basically unheard of), and 100F is very hot but not extraordinarily so. Then you talk to someone living close to the arctic and the converse is true.
All this talk about 0F to 100F being frequently encountered probably reveals your local climate conditions more than it helps define a useful global standard for all humans. We should accept that humans live in more diverse conditions than we intuit and such a scale probably won’t be useful for all.
Now I'm imagining some kind of timezone-like temperature unit that varies around the world, and a "100 things programmers should know about ___" post about all the intricacies and special cases.
Ooh, and it could shift seasonally so that summer temperatures and winter temperatures can both be in the convenient range. And every locality could shift a different amount and at different times of year according to their local climate.
Next, we can look into reforming those pesky mass and volume units…
> That’s a biased view that leads to a scale only convenient for people living in particular latitudes
I mean, the other option is cool vs dead
> We should accept that humans live in more diverse conditions
The second most diverse range of temps in the world is smack dab in the middle of the US: South Dakota up through northern Minnesota. Most years that area experiences -40F in the winter and 110F in the summer.
Celsius maps nicely to the temperatures observed in a typical Finnish sauna. 100C is among the highest typical sauna temperatures (very relaxing in dry air), and afterwards you cool off with water around 0C
Also, having 100C as water temp for black tee and 80 for green tee is nice to remember
This has always been my primary argument in favor of Fahrenheit. It makes sense for humans, which is all a majority of the population really cares about. In addition, it's more granular. Sometimes turning the thermostat up or down by 1C could be too much, where 1F is just right.
In science and math, I can see where having round numbers for commonly used temperatures would be useful, but if 0C and 100C are the only places that happens, it's not that hard to memorize 2 numbers.
You only think it makes sense for humans because it makes sense for you, where you live the same way you feel changing a thermostat by 1F is perfect but 1C is too much: that’s true for you, not universally.
Fahrenheit functionally requires you to be biased in order for it to seem like a good system.
It provides greater granularity in the range of human comfort, without descending into decimals. How is that not more useful for day-to-day human usage?
0F is cold, 100F is hot. I experience both of these temperatures outside where I live every year.
-20C to 40C seems much more arbitrary as a way to measure the zone humans mostly live in.
I would wager that the outdoor and room temperature are an overwhelming majority of human use for temperature. It seems like it would make sense to optimize for how temperature is more commonly used at a population level.
I would say those who see Celsius as a good system are also biased, because they grew up with it and it’s what they’re used to.
The -40C was a typo, should have been 40C, to mirror the 0F to 100F, rounding a bit to make it less silly. It’s been fixed now.
Millions do experience 0F, and it’s ok to not use the full range. At or around 0F is cold, as you move closer or beyond it, it’s cold. As you move closer to or beyond 100F, it’s hot. Most people would likely prefer to never deal with <0F or >100F.
Celcius is pretty intuitive actually. It takes atmospheric pressure into account, Water is pretty abundant on the surface of the planet, and life kinda depends on it. It's a remarkable substance and quite stable. I dont think theres another substance where we can see all three phases with kitchen appliances and still consume it. Equally good for bathing and drinking. I need steam to clean clothes and cook my food. Using water as a benchmark for how we measure temperature is remarkably useful.
With all of those examples, the actual temperature doesn’t really matter.
For drinking and bathing, people go by feel. In the kitchen, the freezer makes water freeze, and the stovetop will make it boil into steam, but exact temperatures aren’t really relevant here either. The same goes for ironing clothes, the iron just does it.
When I think about where explicit temperatures are needed in the home, the oven and thermostat are the two things that come to mind. Water is pretty irrelevant for both of those. For cooking or frying someone may monitor meat or oil temps, but those aren’t water. A hot tub might have an actual temp on it, but those tend to be around 100F, not 100C, as they are meant for humans, not boiling.
Water is an amazing liquid, but I still struggle to see how measuring all our temperatures based on it makes sense.
> When I think about where explicit temperatures are needed in the home, the oven and thermostat are the two things that come to mind.
But in that case in what way is for example baking a frozen pizza from the store at 400 to 425 degrees F more relatable/convenient/natural than 200 to 220 degrees C?
It's not. When it comes to an oven, F and C are equally arbitrary, so it really doesn't matter. Optimize for what people use most, and let the other random uses fall as they may.
OF will still kill you faster than 100F, and most folks aren't comfortable at 50F.
It inspires the following idea: A nonlinear scale where ~72F is 0, and +X represents the same level of heat discomfort as -X represents cold discomfort.
Aren’t you just remembering specific numbers though? Unless you’re trying to boil water unseen so that you can only see a thermometer, the specific 100°C mark isn't that useful.
The temperature water boils at is irrelevant when you can just look at it to see if it’s boiling. Any stove will get it hot enough, assuming you have enough energy.
I actually came around to Fahrenheit for the exact same reason. 0°F and 100°F are kind of the top and bottom of the temperature range I’m going to be experiencing and anything outside that is waaay too hot or cold. In Celsius a large portion of people have to flip to negative numbers regularly during the normal year, and everything between 45°C and 100°C is completely unused.
> 0°F and 100°F are kind of the top and bottom of the temperature range I’m going to be experiencing and anything outside that is waaay too hot or cold.
Food, saunas, the weather, a fever, and much more are often over 100F.
Except 0F being “really cold” and 100F being “really hot” is a personal bias of yours based on where you’ve lived. It’s not true for everyone or everywhere.
And even if it were true, it still wouldn’t work. 100F in a dry environment is nice while, in a humid environment, 100F is awful. Same for 0F, a dry and static 0F is fine while a wet and windy 0F is killer.
There's nothing stopping the use of decimal points for Celsius. Though there's also nothing stopping decimal points in Fahrenheit, the rare instance where an imperial sub-unit doesn't make things go fucky.
I think that both the Celsius and Fahrenheit scales are now defined in terms of Kelvin and a formula. Most if not all of the units of measure are no longer related to their history except for an agreement to make the new units match the old ones at some point.
You can thank Carl Edvard Johansson[1] for that, the inventor of the gage block.[2]
He was the one who decided to make it a convenient value, according to Wikipedia[3]
As a result of the definitions above, the U.S. inch was effectively defined as 25.4000508 mm (with a reference temperature of 68 degrees Fahrenheit) and the UK inch at 25.399977 mm (with a reference temperature of 62 degrees Fahrenheit). When Carl Edvard Johansson started manufacturing gauge blocks in inch sizes in 1912, Johansson's compromise was to manufacture gauge blocks with a nominal size of 25.4mm, with a reference temperature of 20 degrees Celsius, accurate to within a few parts per million of both official definitions. Because Johansson's blocks were so popular, his blocks became the de facto standard for manufacturers internationally, with other manufacturers of gauge blocks following Johansson's definition by producing blocks designed to be equivalent to his.
This makes it relatively easy to handle making metric threads on imperial machines, and vice versa, because you can use 50 / 127 gear tooth pairs to do the ratios.
most tv makers and electronics stores in europe give you the screen size in inches first and cm second. they only come in a few common sizes so the specific units dont really matter.
Speaking of tires, its actually a crazy mixture of units here in the US. You might have a size like P215/65R15 which translates to a radial passenger tire of a 15" rim, 215mm wide tread (sidewall to sidewall), and an aspect ratio of 65 which is a ratio of the sidewall to tread width.
So a tire size is expressed in inches, millimeters, and ratios.
Sure technically yes, but also celsius is now technically defined as just Kelvin plus 273.15. Degrees have technically been redefined as exactly 1.380649×10^−23 joules
[1]: https://youtu.be/esQyYGezS7c?t=226
https://www.gardco.com/product/pencil-hardness-test-kit-astm...
Why offer erasers on these things? The procedure described below has nothing to do with using these as pencils, and at $500 for a pack I can't imagine anyone, anywhere casually drawing with these.
(Is there another procedure, similar to the one described below, except instead of dragging the pencil tip across a surface you drag the eraser across it? )
and you dont need to fit the car into a proper harness tester?
> For the pencil hardness test, reference ASTM D3363, pencils of increasing hardness values are moved over the surface in a precisely defined way until one lead damages the surface. Surface Hardness is defined by the hardest pencil grade which just fails to damage the surface.
> Observe the pencil track. Sufficient pressure must have been applied either to cut or damage the coating or to crush the lead pencil point.
> If neither coating damage or pencil point crushing is observed, repeat the test until a definite observation is made.
> If scratching or damage of the surface occurs, proceed with the next softer pencil grade and repeat the testing process until a pencil lead grade is found which crushes and does not damage the coating.
> If crushing of the hardest lead should occur, the coating is therefore extremely hard and is beyond the measuring range of this test
https://en.wikipedia.org/wiki/ISO_3103
https://www.nist.gov/news-events/news/2020/02/nist-releases-...
Perhaps you would prefer some standard issue meat.
https://www.sigmaaldrich.com/US/en/product/sial/nist1546a
https://www.sigmaaldrich.com/US/en/product/sial/nist2781
https://shop.nist.gov/ccrz__ProductDetails?sku=1196a&cclcl=e...
California/New York prices are easily $0.75/cigg so it’s not that much more expensive.
Thinking of a concept for a restaurant meal along the lines of a calibrated fried spam dinner, that costs ~2k for about a can worth, fried like they do in Hawaii.
Come to think of it, would love to see an “iron chef- calibrated foods” edition.
https://www.youtube.com/watch?v=crjxpZHv7Hk
I have recently realized we imported the western world in the most superficial ways.
You need shitloads of ordinary water to extract a liter of heavy water. And I'd be surprised if there's any superheavy water in that, because tritium radioactively decays.
Fun fact: Heavy water is slightly toxic to humans. If you only drank heavy water, you'd die as it shifts the chemical reactions in your body out of balance. A moderate amount is fine though.
Obviously the luxury bottled water industry is missing out on the potential of D2O and T2O.
https://en.wikipedia.org/wiki/Heavy_water#Production_methods
(There is a reason it is common to drop the century when talking about years, humans are less skilled at numbers over 100)
And I know temperatures in Fahrenheit go higher but it is common to refer to Phoenix as "over 100" even when it's high can peak over 120.
(I'm a little sad the five-digit date hasn't become popular.)
Yep.
> humans are less skilled at numbers over 100)
No, the reason is that the century is constant and therefore carries no information. Where the century isn't constant, it never gets dropped.
No one says 6 even though it has a very reasonable information density for conversations. It is either a relative year or a two digit one.
All this talk about 0F to 100F being frequently encountered probably reveals your local climate conditions more than it helps define a useful global standard for all humans. We should accept that humans live in more diverse conditions than we intuit and such a scale probably won’t be useful for all.
Next, we can look into reforming those pesky mass and volume units…
I mean, the other option is cool vs dead
> We should accept that humans live in more diverse conditions
The second most diverse range of temps in the world is smack dab in the middle of the US: South Dakota up through northern Minnesota. Most years that area experiences -40F in the winter and 110F in the summer.
Also, having 100C as water temp for black tee and 80 for green tee is nice to remember
In science and math, I can see where having round numbers for commonly used temperatures would be useful, but if 0C and 100C are the only places that happens, it's not that hard to memorize 2 numbers.
Fahrenheit functionally requires you to be biased in order for it to seem like a good system.
0F is cold, 100F is hot. I experience both of these temperatures outside where I live every year.
-20C to 40C seems much more arbitrary as a way to measure the zone humans mostly live in.
I would wager that the outdoor and room temperature are an overwhelming majority of human use for temperature. It seems like it would make sense to optimize for how temperature is more commonly used at a population level.
I would say those who see Celsius as a good system are also biased, because they grew up with it and it’s what they’re used to.
Most people never experience anywhere near 0F in their lives.
> -20C to -40C seems much more arbitrary as a way to measure the zone humans mostly live in.
The zone most humans live in does not routinely (if ever) get anywhere near -20, to say nothing of -40.
Millions do experience 0F, and it’s ok to not use the full range. At or around 0F is cold, as you move closer or beyond it, it’s cold. As you move closer to or beyond 100F, it’s hot. Most people would likely prefer to never deal with <0F or >100F.
For drinking and bathing, people go by feel. In the kitchen, the freezer makes water freeze, and the stovetop will make it boil into steam, but exact temperatures aren’t really relevant here either. The same goes for ironing clothes, the iron just does it.
When I think about where explicit temperatures are needed in the home, the oven and thermostat are the two things that come to mind. Water is pretty irrelevant for both of those. For cooking or frying someone may monitor meat or oil temps, but those aren’t water. A hot tub might have an actual temp on it, but those tend to be around 100F, not 100C, as they are meant for humans, not boiling.
Water is an amazing liquid, but I still struggle to see how measuring all our temperatures based on it makes sense.
But in that case in what way is for example baking a frozen pizza from the store at 400 to 425 degrees F more relatable/convenient/natural than 200 to 220 degrees C?
It inspires the following idea: A nonlinear scale where ~72F is 0, and +X represents the same level of heat discomfort as -X represents cold discomfort.
youd still need to include where the discomfort is measured
450F vs 230C does not feel like anything gets easier there. Maybe in some highly technical baking there are some nice deltas that appear?
Food, saunas, the weather, a fever, and much more are often over 100F.
And even if it were true, it still wouldn’t work. 100F in a dry environment is nice while, in a humid environment, 100F is awful. Same for 0F, a dry and static 0F is fine while a wet and windy 0F is killer.
He was the one who decided to make it a convenient value, according to Wikipedia[3]
This makes it relatively easy to handle making metric threads on imperial machines, and vice versa, because you can use 50 / 127 gear tooth pairs to do the ratios.[1] https://en.wikipedia.org/wiki/Carl_Edvard_Johansson
[2] https://en.wikipedia.org/wiki/Gauge_block
[3] https://en.wikipedia.org/wiki/Inch#History
The other day I heard an American talk about a TV being 65 inches. Took me a while to understand they had a 165 centimeter diagonal television.
So a tire size is expressed in inches, millimeters, and ratios.
https://en.wikipedia.org/wiki/United_States_customary_units