exchemist

Yes I’ve always thought it silly to produce fake meat instead of using the whole cuisines out there that are based on vegetables, such as Indian and much of Italian (delicious aubergine ravioli last night, here in Syracuse). Vegetarianism is certainly growing among the Gen Zs like my son and his girlfriend, and they don’t go in for fake meat.

Not according to the report I previously read about it in the Guardian. As @swansont points out there may be a bit of journalistic exaggeration of what NASA is actually claiming though, so perhaps I’m being unfair.

I’m getting a bit cynical about NASA’s claims over this. Inorganic processes could be responsible for what they’ve found. But they need the interest to keep the funding.

???

I'll look out for them. Ortygia, Agrigento, Piazza Armerina, and maybe Selinunte, will be on the list. (My son read Ancient History so these places will be of interest to him.)

Yes Archimedes lived in Syracuse. (Where I shall be in fact, 24hrs from now, for 5 days holiday with my son.) Re N Hemisphere ice loss, could it be something to do with the transport of warm water in the Gulf Stream/N. Atlantic Drift?

Good morning Mr President. So you did send Epstein a birthday greeting, with your signature serving as the pubic hair on a woman's torso. How witty and tasteful of you!

Yes, more or less what I was also trying to say. Like you, I'm chary of the word "random" in this context. It's more a matter of dispersion (of energy), I think.

I don't know how this NCERT material is compiled, but I suspect it will be by various authors contributing different sections on a pro bono basis. What may happen, I imagine, is an author may not know exactly what has been taught elsewhere in other modules and hence what level of knowledge to assume in the student. That might explain this rather ham-fisted attempt to teach integral calculus, sitting in the middle of a piece of physics. It does make it hard for @HbWhi5F , so I sympathise with his or her difficulties with some of this. I don't think these questions are homework, by the way. They read to me like attempts by a student to understand the (not always clearly explained) text.

Yes I quite like your analogy, though I think it needs a fair bit of explanation for our 6th form scholar. Entropy, or rather entropy change, which is what we are talking about in this instance, is notoriously tricky to visualise at the molecular level. Your point, I presume, is that the increase in "diversity", when heat is to supplied to molecules that are mostly initially in the ground state, is greater than if they are already busy cascading among numerous thermally excited states before the extra heat is added.

There is only one now as experienced from our frame of reference, since we are unable to occupy the frame of reference of anywhere else. Speaking about “now” in relation to astronomically distant objects is a fairly useless exercise, as there is no way to experience it. And if they happen to move at relativistic speeds, relative to us, it gets worse because their clocks as seen by us run slow.

Sure. What is your problem?

I'm not sure why you think it is saying it takes more energy when done in finite steps. I don't think the text is saying that. What is giving you that impression? This whole business about finite steps is because when you compress the gas in the cylinder, the pressure goes up. It is to show you that you can't just multiply the pressure at the start by the volume change, or you will get the wrong answer for the work done (too low). The pressure is a function of volume, i.e. p is p(V). So as I said before you need to calculate this as an integral: W = - ∫p(V) dV. If you have studied calculus, you will know that integration is the limiting case of adding up a number of steps, each with a different value of the quantity. (Again as I said previously, I personally think it is mistake on the part of the writer of this text to try to teach integral calculus as a sidebar to a discussion of the gas laws. It's just confusing - and, lo and behold, you have got confused! Some simple calculus is something you need to know to do physics at this level anyway.) But luckily for us chemists, a lot of the time we only need to consider PV work in the context of lab experiments done under ambient atmospheric pressure. Under these conditions the volume changes during a chemical reaction occur under constant pressure, so we can calculate PV work, e.g. to work out enthalpy changes, just on the basis of volume change, without needing to do an integration, i.e. we can say ΔH = ΔU + PΔV. (That would not be true if we were reacting gases, in a vacuum line or something.)

It's not to do with the speed at which heat is supplied though. There is no time dependence in dQ(rev)/T= dS. So I would say it is closer to 1 than 2. Transferring heat at a lower temperature results in it being distributed in more different ways within the substance.

Ah, thanks, so this is the Indian government school material that goes up to class 12 in the final year of secondary education. So you are in your penultimate year of secondary school then. That is useful background to your series of questions.

What book are you using?

The law of the bleedin’ obvious?

What book is this?

This needs care. What are you quoting from?

Re (2), yes. As was explained on one of your previous threads, the convention is that energy lost from the system is -ve and energy added to it is +ve. So an exothermic process will have a -ve enthalpy change (ΔH<0). In this case the more you dilute HCL the more energy is released (it gets warm), so the change is -ve. Yr (1) involves calculating the difference between 2 -ve quantities, that's all. Don't get bamboozled by all the -ve signs.

But that's not what I wrote. What I wrote was that the Big Bang theory "depends on" GR. Which it does. Nobody would disagree with you that observed reality trumps any theory. That's obvious. But relativity, both special and general, fits observation, so it is congruent with reality as far as we can tell at the moment. In SR, foreshortening in one frame of reference corresponds to time dilation in the other (I always like the cosmic ray induced muon example to picture this). No "mutilation" of anything is required: it all fits nicely.

I'm the same age as you, then.😊 I think you are rather overdoing things if you think the absence of a preferred frame of reference is somehow an argument against God. Don't forget the Big Bang theory, which depends on general relativity, was originally proposed by a Catholic priest, Mgr. Lemaître: https://en.wikipedia.org/wiki/Georges_Lemaître As for predictions that cannot be tested, the point surely is that for a theory to be scientific it must make testable predictions. General Relativity obviously does this. Even our GPS systems wouldn't work without GR. However, I don't think that means that every prediction or speculative extrapolation that one can make from it necessary has to be testable. As for Einstein's "spooky action at a distance", my understanding is this was one of Einstein's rare errors in that in modern physics there is no such thing. Quantum entanglement does not imply any instantaneous communication between the correlated entities.

OK, evidently there haas been some correspondence about lightning and Einstein outside the thread, that I was not party to. I'll leave to the others who seem to understand what you are referring to.

This is all over the place. There is no "parallel cause and effect". As already stated by @MigL it is a principle of relativity that information, however transmitted, cannot be sent faster than c. So this idea of yours is wrong, at least wrong as far as modern physics is concerned, so wrong to the best of our knowledge. By the way a "pneumatic type" transmission mechanism take time to react, as pressure in a gas takes time to build up and a fast change in pressure at one end of a pneumatic tube will produce a pressure wave that will travel down the tube at quite a modest speed. You then glitch and start burbling about lightning strikes on trains and Einstein. What is all that about?

Yes that is excellent, except for the implicit misogyny. Sessile females etc.