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John Cuthber

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Everything posted by John Cuthber

  1. I think you just discovered Kirchhoff's radiation law. https://en.wikipedia.org/wiki/Kirchhoff's_law_of_thermal_radiation
  2. In all sensible probability, nine lives won't be enough.
  3. Do you understand that those classifications are hierarchical? All rosales are rosids All prunus are rosaceae And all of them are plants
  4. With a lot of trouble and care (and a mass spectrometer) you can measure acid base equilibria in the gas phase with no solvent present. Many people have got PhDs by doing this, but I'm not sure it's had much wider use. (By wider, I mean outside the lab) You don't get "H+" ions in water. You get a hydrated version, typically modelled as [H9O4]+ So you are almost always looking at how strong an acid is compared to water. In principle, if you have just liquid ammonia, there are always some protons around to soak up. They arise from ammonia acting as a base. 2 NH3 --> [NH2] - + [NH4]+ The extent of that reaction is tiny, but not zero. (It's about 1 in 10 ^33)
  5. A Post-it note? https://www.staples.co.uk/office-supplies/writing-supplies/correction/post-it-cover-up-and-labelling-tape-25-4mm-658h
  6. No, or at least, only very slightly. More sugar would draw water in from the surrounding tissues (and from the blood) and that would dilute the acid a bit, raising the pH.
  7. Does the universe have a calendar? How did/ does it know when to switch the expansion on and off?
  8. And, if the universe is accelerating away from me, and has been doing so eternally, why is (any of) it still here? The question was "What makes you think the universe was "made up" and hasn't always existed?"
  9. Among other things... https://en.wikipedia.org/wiki/Olbers's_paradox
  10. Every 10 minutes the temperature/ humidity sensor in my garden sends data (by radio) to a display in my house- something like this. https://www.weathershop.co.uk/technoline-ws9130-weather-station (Mine is a different brand) And some device like that is vastly more likely to be the source of the RF which you see than any sort of "attack". If you are experiencing health problems you should consult a doctor.
  11. https://en.wikipedia.org/wiki/Glass-ceramic#Glass_ceramics_in_cooktops And "An interesting property of these glass-ceramics is their thermomechanical durability. Glass-ceramic from the LAS system is a mechanically strong material and can sustain repeated and quick temperature changes up to 800–1000 °C. The dominant crystalline phase of the LAS glass-ceramics, HQ s.s., has a strong negative coefficient of thermal expansion (CTE), keatite-solid solution as still a negative CTE but much higher than HQ s.s. These negative CTEs of the crystalline phase contrasts with the positive CTE of the residual glass. Adjusting the proportion of these phases offers a wide range of possible CTEs in the finished composite. Mostly for today's applications a low or even zero CTE is desired. Also a negative CTE is possible, which means, in contrast to most materials when heated up, such a glass-ceramic contracts. At a certain point, generally between 60% [m/m] and 80% [m/m] crystallinity, the two coefficients balance such that the glass-ceramic as a whole has a thermal expansion coefficient that is very close to zero." from teh same page.
  12. The actual data you need is a Henry's law constant. https://acp.copernicus.org/articles/15/4399/2015/acp-15-4399-2015.pdf then you can calculate how much stuff gets into teh vapour phase from a solution of a given concentration and then you can compare that against the permitted concentrations. Good luck. You might also want to know about these. https://assets.publishing.service.gov.uk/media/5a7ce177e5274a2ae6eeb560/scho0307bmkt-e-e.pdf
  13. I mean that it's impossible to define your speed with respect to a vacuum. (This makes life rather difficult for traffic police in interstellar space)
  14. If you are heading towards the transmitter really fast, a radio wave is light. And a vacuum can't tell how fast you are going.
  15. The simplest way to achieve the "if nothing else is available" pollination is simply to make sure the ovaries are active a while before the anthers are.
  16. It's "worse" than that. Even just one tree pollenating another will produce many different crosses from countless possibilities- in the same way that we are not (usually) the same as our brothers + sisters. Every year, every seed in every apple will be genetically unique. That's (part of) the reason why they usually propagate commercial varieties from cuttings. I understand that some plants will self pollenate, but leave it to the "last minute" They only do it if no other pollen is received. They seem to have evolved to recognise that evolution is a good thing. This makes them "better informed about evolution" than some people I know of.
  17. There are some reagents (Like LiAlH4) which get used a lot in exam questions and textbooks, but not so much in real life. On paper they do the job. In practice they tend to set your lab on fire, and chew through your budget. Cr(VI) based oxidants are a bit too carcinogenic to be popular in industry. (Yes, I know, there are exceptions. The difference is that IiAlH4 might be your first choice in an exam, but it might not be in industry.
  18. " how can be advertised at more intensity than the sales of automobiles with a $50k sticker each ?" How often does the typical user buy (1) Viagra (2) A car ? The big cost of bringing a drug to market is all the testing. Having sold many pills at $40 they have paid for that. Now they only have to cover their costs, so the price has dropped It's interesting to look at the variation of price between manufacturers. https://bnf.nice.org.uk/drugs/sildenafil/medicinal-forms/ And now, it's just a commodity like bread. It gets advertised so people buy a particular brand.
  19. If you dissolve "aluminium" in alkali it turns black because other elements present in the alloy (notably copper) don't dissolve and very finely powdered metals are black. Hydrogen gas is not "choking" but a spray of sodium hydroxide solution is.
  20. They say the best time to plant a tree is 100 years ago and the second best time is now. I think the same logic applies to removing them. Having said that, I guess cutting them while they are dormant will trouble them less than when they are in full swing. You can find data on when is a good time to prune trees; and then do your best not to follow it. https://silveroaktreesurgery.com/article/a-guide-to-which-uk-trees-to-prune-in-late-spring-and-summer
  21. They seem to have found a less bad way of doing the wrong thing. And, among other issues, helium is not a renewable resource.
  22. " most of us on the outside of science looking in are getting a little tired of this big bang B.S. It's time to move on" Yes. Move on from being "outside of science" by learning a bit and coming inside.
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