exchemist

Thanks, that's helpful. What occurs to me about the graph is that they have chosen a scale and a range that makes the effect look as small as possible. We are in reality concerned with the range from 280ppm (the level at the end of the c.19th) to ~400ppm +/- 50 for scenarios in the recent past, today and the near future. So be useful, the graph should be scaled to show the effects within that range. On that basis it would be clearer that, even assuming the chart is correct, which I can't verify, the effect of an increase from 400-450ppm would be about 50% of the increase from 350-400ppm. So less rapid, sure, but still very substantial, and nowhere close to reaching some sort of asymptote of course.

On another forum a climate change denier posted this graph: At first glance it looks like no more than the expected exponential reduction in intensity with concentration of the absorber predicted by the Beer-Lambert law. Has anyone come across this being used as a counterargument to climate change science, is the implication true that further increases should have a proportionately lesser effect and what relevance does that have to the models used to predict climate change?

Re your first, apparently yes. Re your second, no, but that has nothing to do with anything physical.

As this is the person who once tried to convince members of another forum that you can be strangled by your own thymus gland in cold weather, nothing is off the table. 😄

I thought it was copper chromite that was commonly used as a decarboxylation catalyst.

I note the introduction of a new topic, in an irrelevant manner. This is a tediously familiar pattern.

I don't think you need to be that extreme. I have washed items with strong colours at 40C for years, with absolutely no trouble. But I would certainly not try 60C, at least not in a mixed wash. That's for whites and cream-coloured things (I have some sheets and towels that colour) only - plus those notorious maroon towels, which I have to do on their own, or with red items - I have some red polo shirts. (Towels really do need 60C or they can get smelly after a bit.)

No, you know me better than that.😆

And here comes the next item, in the drip-feed of crap to keep the roundabout of pointless dialogue spinning: dinosaurs.

As does the deliberately erratic spelling, color and colour in the same sentence, phisics (really?) etc. Timewaster.

Do you mean this? 1mm every 5secs would be 1.2cm/minute, so it would take 25mins for your feet to advance 1ft along the bath, by which time I’d have thought the water would be getting cold. But I suspect the phenomenon may involve some unnoticed feedback between the apparent weight of your legs and your muscles, i.e. not a pure physics problem. You may subconsciously relax progressively as your feet move and more of the weight is supported by the water. But it’s a speculation. It could also be some kind of slick-slip due to the movement of the skin, I suppose.

Haha, like “Motor Daddy and the Motor Boat” on sciforums, perhaps. That too became a standing joke.

Was that one of Theorist’s?

Aha, thanks very much. So would it be fair to say QFT is the mathematical underpinning of QED? I suppose it also plays the same role in QCD, doesn't it?

Yes you need not just QM but QFT, or QED (as a mere chemist, I remain a bit hazy about the distinction).

Zero point energy, at least, is fairly easy to grasp. All you need is the idea that in QM there is a ground state, in other worlds a lowest energy state that a given system can occupy, and that, in this state (depending on what kind it is), it may be that some residual energy remains present. The electron in the ground state of the hydrogen atom, for instance, still has some potential and kinetic energy. That is zero point energy, i.e. energy that remains in the atom. The same is true for the vibrational ground state of a molecule in which 2 or more atoms are joined by chemical bonds, which vibrate thermally. They still move a bit, even at absolute zero, because there is residual energy in the vibrational ground state. (In molecular rotation, on the other hand, the ground state has no residual kinetic energy, so there is no zero point energy of rotation, i.e. molecules do stop spinning at absolute zero.) What people find harder is the concept of a zero point energy of the vacuum. That will require more reading.

Nowadays that is a rather out of date view. A lot of misconceptions have arisen, historically, due to the choice of words made when originally formulating QM. They spoke - and we still speak - of "observable" properties and "observers", "observation" collapsing the wave function and so forth. Some people thought that "observation" implied a conscious entity to do the observing. But a moment's reflection shows you that can't make sense. Does anyone seriously contend that the reading on the dial changes when the observing experimenter goes off to get a cup of coffee? And what if the experiment is "observed" by the laboratory cat? Or a passing wasp? It's bonkers. The modern view is that it is interaction with another quantum system that collapses the wave function. So that can be part of a measuring device, whether or not anyone is looking at the measurement. Those people nowadays that maintain a role for consciousness in QM tend to be quantum woo charlatans like Deepak Chopra.

Yes it seems the fat of grass-fed animals contains some ALA.

Buoyant in what medium? Or do you just mean lighter than air at sea level pressure?

Who is wrong?

On the contrary.😉

I haven't played these synthetic games since university, nearly 50 years ago now, but it seems to me a start can perhaps be made by recognising the class of of molecule you have on the left. It's a particular kind of aldehyde, which undergoes particular reactions. Have you identified what it is?

Yes, the killer at present for heat pumps is their high cost and the cost of adapting existing heating systems to the lower temperature heat they put out. For new housing not such an issue, but in a country like the UK, with a lot of housing stock more than a century old, it is a big barrier to adoption.

Eh? No, Elizabeth David wasn't Italian. It comes from a book called Polpo, named after a Venetian-style restaurant in London, which I got as a present some years ago. But jambon persillée is something you see at the charcuterie counter in many French supermarkets. It's actually not as good as the Polpo version, but it's the same general idea. The recipe in fact calls for a shank, so you get some gelatine from the connective tissue, but I just use a supermarket bloc of smoked ham, which works fine. But it did take me several tries to titrate the ratio of gelatine to stock so that it sets to the right consistency. (If you have some stock and gelatine mixture left over, you can let it set in small glasses and serve it as a savoury jelly appetiser, to eat with a teaspoon. It's rather good actually. I've toyed with the idea of embedding a quail's egg in it, to make it more chi-chi, but I'm not quite cheffy enough to have got round to it. )

The use of ham stock in soups etc is fairly standard. This seems to be an extension of that principle. My favourite ham recipe is a ham and parsley terrine, in which smoked ham is simmered with carrot, onion, leek, celery and parsley stalks, allowed to cool and cut and torn into small chunks. These are mixed with mustard, a chopped raw shallot, some vinegar and quite a lot of chopped parsley and put in a terrine dish. One then strains and seasons the stock in which the ham was cooked, adds gelatine and pours over the ham mixture. This is allowed to set. It can be cut into slices to serve but the tricky bit is getting enough gelatine so it does not fall to pieces, without it becoming too rubbery. Best cut when cold from the fridge, but should be allowed to come to room temp before eating so the flavour can develop. The French call it jambon persillée. But my recipe comes from an Italian recipe book.