John Cuthber
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Everything posted by John Cuthber
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Probably not because we can get creative about the way we express them. https://en.wikipedia.org/wiki/Knuth's_up-arrow_notation
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pH, phenol red, 560nm wavelength, absorbance
John Cuthber replied to jlbarkley's topic in Applied Chemistry
Buffer solutions and/ or a pH meter. But you will run into a problem. You can set up a calibration and draw a graph of absorbance vs pH. But it will depend on the concentration of the dye as well as on the pH. It is difficult to be sure that you always have the same concentration of dye. Most dyes are a bit unstable and a lot of them are not supplied as pure materials, but as crude products containing salt etc. So, you would have to make a fresh calibration for each set of samples. If you are going to do that- and use a pH meter to do it- you might as well just use the pH meter to determine the pH of your sample. But there's another pitfall in this analysis. pH meter probes always carry some buffer into the solution which you are trying to measure. And that changes the pH of the sample. To measure the pH of very dilute materials (like drinking water or even river water) you need specialist equipment. I suggest that you contact the people who make pH meters and ask for their advice. -
does a reaction occur when CaCO3 and NaHCO3 are added?
John Cuthber replied to observer1's topic in Chemistry
What were you expecting? Why would you post that in a thread where someone has actually done the experiment and told you that there is " LITERALLY NO REACTION"? -
Not if you apply it to people who are dead. Equally interestingly " Guinness retired the "Highest IQ" category in 1990 after concluding IQ tests were too unreliable to designate a single record holder." From https://en.wikipedia.org/wiki/Marilyn_vos_Savant Fundamentally, IQ is a measure of how well you do in IQ tests and it measures nothing else.
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Yes. So? Here's an interesting observation. The IQ test was designed to identify school kids who were struggling with education in order that they could get extra help. But the people you see on the internet asking about IQ are neither schoolkids, nor do they have cognitive / learning issues. They just sound like it.
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The Magic Capacitor: a short science fiction story.
John Cuthber replied to JacobNewton's topic in Speculations
Yes. And he's quite honest about the fact that they are illusions; not real. And would you accept this as proof of a flying pig? or do you understand that video is quite easy to fake? -
Will science ever stagnate and come to a halt?
John Cuthber replied to JacobNewton's topic in Other Sciences
"Will science ever stagnate and come to a halt?" Most Friday afternoons -
How to separate a container containing NaHCO3 and CaCO3
John Cuthber replied to observer1's topic in Chemistry
I'm fairly sure that sodium bicarbonate will float in methylene bromide, but calcite will sink. -
The Magic Capacitor: a short science fiction story.
John Cuthber replied to JacobNewton's topic in Speculations
Yes there is. The reason is science. Sure Did you really think it was magic? Would you like to buy Tower Bridge? -
I think they look cute. But I still don't think any of this really counts as a wheel.
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The seeds are alive, and they travel on "wheels"
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So, aside from the issue of connecting blood supplies / nerves etc, and the fact that wheels are only useful if you have a "road" and the challenge of finding a use for half a wheel? ... tumbleweed...
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WAUKESHA 88 CRAZY !!!! MONDS PROCESS?
John Cuthber replied to harryjackson's topic in Inorganic Chemistry
I'd be surprised if you can't find some metal recycling place that's prepared to take it. Nickel is quite valuable. The Mond process just isn't something that works on a "home brew" scale. -
The reaction does happen, but it is very slow. You can increase the rate of reaction with a suitable catalyst e.g. https://en.wikipedia.org/wiki/Urease
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Why does the thread title say "carbonate"?
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OK. So, without the protective effects of ethanol 30 g of methanol will cause harm. But a litre of ethanol would probably kill you. So, as long as the methanol content is less than about 30 grams per litre or 3% the ethanol will kill you before the methanol does any harm. 30 grams per litre 3000 grams per hectolitre or roughly 2 times higher than the highest figure in the table will be "safe" because of the antidote also being present. OK, so the table can not be anything to do with health- let's face it, the healthy option doesn't include drinking much hooch. The reason is that they don't want people adding industrial meths to the authentic product. You could, realistically get away with adding a bit of meths to something like fruit brandy and blame the methanol of pectin. You can't do that with gin. So it's a practical measure of how much methanol indicates that the product has been adulterated. A quality control issue, rather than a health issue.
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You are missing the fact that the levels are not set on grounds of health. The methanol content is an indicator of what "good practice" achieves. Because there's a lot more pectin in some of the substrates than in others, the methanol levels will be higher. The light fraction is full of acetaldehyde which makes engines knock like hell. Also, there are miscibility issues with methanol and saturated hydrocarbons.
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Find optimum radian and diameter of convex mirror
John Cuthber replied to Alferd's topic in Classical Physics
Since a flat mirror is cheap and easy and it would work I guess it's optimal. -
Swimming with crocodiles - How is that even possible?
John Cuthber replied to MathHelp's topic in Biology
Reminds me of selling nuclear shelters... No dissatisfied customers ever complained. -
I would like to know your opinion on this hypothesis?
John Cuthber replied to asd2791's topic in Speculations
Nope. https://en.wikipedia.org/wiki/Flurothyl Much more importantly, high pressure oxygen- which can clearly be breathed- is a convulsant, not a narcotic. -
Enough have failed that we know they really won't "last forever". That looks a bit like a "No true Scotsman" argument.