exchemist

There's an explanation of the process for separating rainwater from sewage here: https://www.wavin.com/en-en/News-Cases/News/Pros-and-Cons-of-separating-rainwater-from-sewers-to-prevent-sewer-overflow-in-urban-areas From the description it does not look as if any country has really embraced this idea fully, though there seem to be some pilots at municipality level, Vancouver perhaps being one. It is evidently a very costly and disruptive exercise to retrofit a twin-pipe system, though I suppose it could be put in place on new housing developments if planning regulations were changed to require it.

I was discussing the post to which I was responding, strange to relate.

They seem all to have observed something, but apparently nothing with a radar signature. Irritatingly this is presented to emphasise mystery rather than to dispel it, so no helpful details are provided. But if what the picture shows is correct in that the sun was just rising above the clouds, and what they saw was a bright light, my suspicions are aroused that this could have been some effect attributable to sunlight.

That does not happen.

I don’t believe you. Anyone advancing a theory scientifically would be able to present the observations that the theory tries to account for.

OK so let's see some of this "meticulously documented" research, then.

So no research then.

Where’s the research, then? Who did it, how and what was observed?

So far so good. Thanks for addressing so quickly. !

The problem with the real thing is there no real way to speed up the deposition of CaCO3 very much - though I seem to get quite a bit blocking the taps at home within a matter of years. I've never heard of making stalactites or stalagmites with sodium silicate and Epsom salts (MgSO4.7H2O) but I can see it might work. The picture actually shows stalactites rather than stalagmites. If you are really after stalagmites, then making a chemical garden might suit your needs. This too involves sodium silicate. Instructions here from the Royal Society of Chemistry: https://edu.rsc.org/experiments/making-a-crystal-garden/416.article . This, being designed for chemistry teaching, proposes various chemicals that you would need to order specially. But you could also try iron (II) sulphate, greenish but may go a bit rusty-brown, which is sold in garden centres for calcifuge plants, and copper sulphate, blue, which is or was sold, mixed with calcium hydroxide (I think), as something called Bordeaux mixture to control disease on plants, as well as a Epsom salts.

Dunno, but the OP seemed to want it.

No. It is as @Genadysays. Suggest re-reading my post and trying to get hold of the idea of how an image is formed. What I have been trying to explain is that all the light that hits your eye from the letter Q is focused , by the lens, on just one part of your retina ONLY, where it forms the shape of a letter Q (upside down, but don't worry about that for the present). Similarly for the light coming from the other letters. You could try reading this, which explains image formation by a lens at greater length: https://www.physicsclassroom.com/class/refrn/Lesson-5/Converging-Lenses-Ray-Diagrams

Eh? I think you must be quoting @Kassander.

I don't think this scenario is like buoyancy in a fluid. I would think the relevant dimension of the superconductor is the area it presents to the magnetic field. But I may be wrong - this is outside my area of knowledge.

For a start, aiming a laser at your eye is an idiotic thing to do, as it is likely to blind you. NEVER do that. Secondly, it looks as if your problem in understanding here is that you do not know some basic optics. The role of the lens in the eye is that it allows an image to be formed, whereby all rays of light from each point in an object that reach the eye, regardless of exact direction and regardless of which point of the the lens they strike, are focused onto a single point on the retina. This property of lenses results in the formation of an image of the object on the retina, rather that just an undifferentiated blob of light. In the diagram below the upright black arrow is the object. two light rays from the tip, going in different directions and hitting different parts of the lens, are shown. The lens makes these converge, to form an upside down image of the tip of the object, at a certain distance behind the lens. That is what happens in your eye. A laser is a bit special in that all its light rays are parallel. That causes the lens to focus all of them onto the same point. So a laser aimed at your eye would look like an extremely - in fact dangerously - bright single point of light. That's why it can blind you.

What has buoyancy in water got to do with this problem?

But he has a point. It took me a while to decide whether you were asking a serious question or just being facetious. In fact, I'm still not sure.

There is now a pending lawsuit in Australia, from a man who was wrongly accused by ChatGPT of a criminal conviction for fraud. And this article in today's Guardian makes chilling reading: https://www.theguardian.com/commentisfree/2023/apr/06/ai-chatgpt-guardian-technology-risks-fake-article. Just when you thought the churning of false and mad stories around the internet could not get any worse, it is given a further boost by being actually fabricated by this bloody Artificial Stupidity robot. The sheer irresponsibility of these people is just amazing. (And of course we have a live example of how it can't be trusted on science, on this very forum.)

Hopeless, as they are immiscible with water.

I should have thought, rather, that it tends to follow an asymptotic curve, developing further all the time, but in smaller and smaller optimisation stages.

The study of what it is that makes the other sciences exhibit the patterns they do. Physics is the scaffolding on which the other sciences are erected.

Can’t be that or the magnetic pressure would be a function of how the field was applied.

Is a superconductor different, and if so why would that be?

I've come across an explanation , which I don't fully understand, for why a superconductor in a magnetic field experiences a force (the Meissner effect). It is said that eddy currents will be triggered in the superconductor which will form a perfect mirror image of the magnet, with like poles adjacent, so a repulsive force is generated. What I don't follow about this is I thought eddy currents were generated by a change in magnetic flux density, not by a static field. Does anyone know more?

To be honest I think to make progress in understanding this topic we should forget ChatGPT and have one of our physicists talk us through the Meissner-Ochsenfeld effect a bit. ChatGPT is basically as thick as mince and just plagiarises stuff it looks up on the web that it hopes is relevant, based on some algorithm. There's no reason to expect it to be able to do this stuff properly. But does it give you references for where it gets its formulae from? If we can read those sources we might get somewhere. Meanwhile, I've had another look at the Wiki article, which gives a remarkably simple formula for something called the "magnetic pressure" that a magnetic field exerts on a superconductor. This is Pmag = B²/μ₀, where P is force per unit area at the superconductor/field interface, in Pascals, B in Tesla. Here's the link: https://en.wikipedia.org/wiki/Magnetic_levitation What happens if you plug in the numbers for the Earth's field?