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- Hacker News
- 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.by artisinal
- kelvin still has reference points - absolute zero and tripple point of water
good luck choosing which water, tho
by NooneAtAll3 - Now do metric vs imperial.
- Strange statement to say in an article specifically about water, of which both the Kelvin and Celsius derive their scale.by fps-hero
- 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.by analog31
- 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...by warmdarksea
- Kelvin does still rely on each degree being 1% of the way between freezing and boiling so it kinda does rely on a variant reference pointby xgulfie
- You want numbers to be understandable and K produces illogical numbers.
(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.
by Guvante - I can't help but read VSMOW as Very Standard Mean Ocean Water.by tomsmeding
- Does NIST have a restaurant?by rainmaking
- Idk I feel like if you bought in bulk you would get a discount on the additional mL purchased.by fionic
- How does the water taste?
- like what you most want but most can’t have, and what you most can’t have is what you already once had, but lost.by deadbabe
- Completely decadent, with only a slight aftertaste bearing a noticeable hint of regret . . .by fuzzfactor
- Slap the 'organic' label on it and sell it at restaurants for $150k/L. It will sell.by 1970-01-01
- I hadn't put much thought into why it was called "Vienna Standard Mean Ocean Water".
My first hint should have been that Austria is landlocked.
- A US gallon of deuterium water costs roughly $2,600 to $3,800, while a gallon of pure tritium water (super-heavy water) would cost about $44 million.by spullara
- Makes me want to go to the ocean and start filtering out water somehow.by BizarroLand
- How much volume is that for the rest of the world? Really unscientific article.by a3w
- Reminds of me of the "most expensive peanut butter" at ~$2.44/g - sold by NIST, I assume for some sort of peanut butter factory process calibration: https://shop.nist.gov/ccrz__ProductDetails?sku=2387by sudb
- You can still make cookies out of reference and/or lab materials :)by ajsnigrutin
- 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.
- SRM 2387 pairs well with a cup of ISO 3103.by cjs_ac
- 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".by cyphar
- 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.by rwmj
- I at first thought you meant taking hydrogen gas and burning it in O18, which seems even simpler than bulk processing water.by 0cf8612b2e1e
- Not an expert, but...
The use case for this water is calibrating ultra-precision instruments. The use case for those instruments is measuring water with normal-ish isotope ratios.
Calibrating your ultra-precision instruments to a point far away from their normal use case is asking for trouble.
by bell-cot - At the very least that has the advantage that it's possible to make more of it, so you aren't dependent on a limited sample of standard water.by thayne
- 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.by barbegal
- 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 VSMOWby jarenmf