exchemist

Yes I would definitely use deionised water and a fresh, untreated cabbage. But I've never done this myself, I should stress. My experience is only in the kitchen, where I find the juice from red fruits goes distinctly blue when I rinse dishes. Almost all of them get the purple colour from anthocyanins, I believe, from blackcurrants to aubergines and red cabbage, so the same behaviour is expected, modified only by whatever acidity there may be in the fruit or vegetable involved.) The reason for the colour change is quite interesting. These are conjugated ring systems with extensively delocalised π-orbitals. Protonation and deprotonation alters the bonding and thereby changes the energy gap between ground and first excited state, so that the molecule absorbs a different chunk of the visible spectrum.

These show different ranges in detail but in all cases the pH is 8 +/- 0.2or so. So red cabbage should be blueish, if there are no acids around to distort it. But as @John Cuthber points out, at such a neutral pH, very small changes in H+ concentration have have a big effect on the value, so any traces of acid contamination can alter it quite a bit.

Paul, when I cook red cabbage the problem is to stop it turning blue when I sweat it with butter or add any water (I live in a hard water area). The normal way to do this in cookery is by adding acid, e.g slices of apple, or vinegar. How did you prepare the indicator? Did you buy a fresh red cabbage and extract the anthocyanin yourself, or does it come from something in a jar. If the latter, it will almost certainly have some sort of acidifier in it, to keep the colour.

If it goes black when heated, you have some organic material present.

Daily Mail?

You are right. You've tried to explain your idea - and nobody here thinks it is a good one, for reasons they have explained. So that's that, really.

Love it! This is just the sort of stream of impenetrable management bullshit that made me so grateful for the chance to take early retirement. 😃

On a point of factual detail, this seems to be untrue. According to this table: https://en.wikipedia.org/wiki/List_of_Nobel_laureates_by_country The US has 403, the UK 137, Germany 114, France 72 and the rest of the EU countries between them have 171, or, if one excludes the recent admission of former Warsaw Pact countries, 131. The UK does well, it is true, but one needs to bear in mind the advantage of language. Language is important for information sharing and collaboration in science. When I was at Oxford in the 1970s, the old-school dons were still advising chemists and physicists to learn German, as so much of the good research had been written in German. But in fact English was already becoming pre-eminent and that has of course continued. France, a country comparable to the UK and Germany in population and intellectual tradition, has done well, all things considered. So in Europe we have the big 3 industrial economies - the UK, Germany and France - dominating, which is to be expected. In any event, Nobel prizes are not much use as a measure, if your aim is to contrast a supposed love of theory with supposed excellence at practice. Nobel prizes are awarded for theory just as much as for application, if not more so.

Aha yes of course.

Surely (1+√5)/2 : 1 ?

Agree strongly with this, especially your last point. I must say I have always objected to the narrow view that education is merely equipping students for a job, which seems to be what runs through @Erina's approach to the topic. People change careers, sometimes radically, fora variety of reasons. They need a rounded education to do that, not just what is necessary for one particular career path. Even more fundamentally, education should equip them to get more out of life in the round, not just to do a job of work. Time spent teaching them how to read literature, how to appreciate the arts, how to understand history, are all helpful to an intelligent enjoyment of life. These things can give you some independence of your circumstances - even an unemployed person can read a book - a way to enjoy your leisure time more productively, and a better sense of balance in your life. The most enduring things I got from my schooldays, apart from an interest in physical science, were choral singing and rowing, which have been features of my life ever since. And as I get older I find the history I learnt is becoming useful, not least as that is what my son has chosen to study at university. So we can still have a conversation about his studies, even though I went the STEM route. So yes, let's teach our children broadly, so they can pick routes from a variety, have the flexibility to change horses if they need to, and are equipped to stay sane and happy. Most private schools in the UK are non-profit entities. They charge a lot because they are in an arms race with their rivals for better facilities and better exam results.

You can always spend more on health but we spend too little, given the ageing population, relative to our peers. The basic problem is the Tory pretence that we can have an EU level of welfare with US level of taxation. But I'll stop here as I've realised I'm taking the thread off-topic.

Sometimes I wonder if this is the approach of the British Tory party to our National Health Service: starve it for years, demoralise the staff and then say, “Look, it doesn’t work.”

Knowing the difference between "refute", "rebut" and "disagree with", and between the singular and plural of criterion, would be a start. 😉 More seriously, surely the criteria for a new teacher are subject knowledge and evidence of the ability to teach, i.e. to motivate pupils to enjoy the subject and be able to show that they have learnt effectively, e.g. by good exam results. (Plus the usual hygiene factors of course.). But is this what you are interested in, or is it what should be in the syllabus? From your previous posts it feels as if the latter is more what concerns you.

Yes, we know what a microwave oven looks like. Your question has been fully answered, several times now. You are behaving like a neurotic timewaster. Kindly stop this nonsense.

Ah, so I now see. All power to your (collective) elbow, then.

I can't really follow all this but in any case Dave has fixed it. And the malicious-looking spam has gone, too, al hamdulillah!

Yup the ad tab is gone and so is the problem, apparently. Well done!

Now I can reply on the Mac, apparently. Have you done something? (The ad tab is no longer appearing.)

Nope still happening. Could be connected with a new advert tab that comes up from the bottom of the screen on the Mac, but not on the iPad. Seems the screen freezes if I scroll down far enough to touch it. Use from iPad seems OK however.

Some teething troubles. Screen scroll can freeze and cursor can disappear when responding using Quote button. This happens on Apple Mac running Safari on Monterey 12.6.4. However I seem able to use the site from my new iPad. Very odd.

No. The surface I am referring to is the enormous surface area of the micropores in the gel, not just the visible surface of the beads. This stuff is like a sponge, full of microscopic tubes and holes, and water is adsorbed on all the internal surfaces. It make no difference if a bead splits in half or something. You can read more about what silica gel is and how it works here: https://en.wikipedia.org/wiki/Silica_gel

Because it is adsorbed on the surface. It is stuck to it and only heat will dislodge it.

No. No.

I'm not a fan of this idea. My mother taught English at A-level for many years in the UK state system and one of her perennial challenges was parents that had limited ideas about what was good for their children. She fought for years with parents who didn't want their daughters to go to university, or who wanted them to study something that led to an obvious job, rather than the subjects they enjoyed. If the parents choose what subjects to fund for their children, you would risk removing the ladder that lets children climb to reach their academic potential. Even in the UK private sector the school sets out the curriculum and the parents go along with it.