Wikipedia:Reference desk/Archives/Science/2024 April 1

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April 1

Converting gas-home to electric-home.

Apologies that this is somewhat of a real estate question. In Chicago home we are gas-furnance and gas-stove. I'm thinking about converting them both to electric-furnance and electric-stove. In which the companies would not remove the gasoline pipes, they would just turn them off. Do electric homes sell better? Supposedly an electric stove will cost more than a gasoline-stove, but a few years ago we already installed solar panels so our electric bill is cheaper. My mother's homes in southern California are all electric stoves, does anyone know about Florida homes? Are there parts of the U.S. that have slowly been converting gas-homes to electric-homes?

Also the price of oil goes up and down. Per barrel. But the gasoline entering homes is called natural gas. Does that also go up and down with oil going up and down? Or are they separate economies? Thanks. 170.76.231.162 (talk) 17:03, 1 April 2024 (UTC).

Gasoline and Natural gas are entirely different things. I very much doubt that you have gasoline piped into your premises. AndyTheGrump (talk) 17:08, 1 April 2024 (UTC)

Okay you're right. Here's a natural gas price chart. https://markets.businessinsider.com/commodities/natural-gas-price When you click on 3y or 5y, why was the price so high in Aug. 2022? 170.76.231.162 (talk) 17:15, 1 April 2024 (UTC).

From personal experience electric ovens are better than gas, but gas hobs are much more controllable. Martin of Sheffield (talk) 17:20, 1 April 2024 (UTC)

Induction hobs however work very well. I recently switched from gas to induction and consider it an improvement. Keep in mind though that not all cookware is suited for induction. PiusImpavidus (talk) 09:02, 2 April 2024 (UTC)

The high price in august 2022 was the result of economic sanctions against Russia, a major exporter of natural gas. PiusImpavidus (talk) 09:09, 2 April 2024 (UTC)

(edit conflict) There's an indirect relationship between the two, see: The Weak Tie Between Natural Gas and Oil Prices. Alansplodge (talk) 17:23, 1 April 2024 (UTC)

Gas heating (including stovetop cooking) is going to be more efficient and cost-effective than electric in colder climates, including Chicago, for the time being. But there are a number of considerations to weigh counter to that. In terms of energy efficiency (as a rough estimate of long-term base costs, maybe), then the fraction of Chicago's electricity fueled by renewables is an important consideration, especially because US subsidies for renewables will likely increase while those for fossil fuels like natural gas will likely decrease in future. Also, for electric interior heating, a heat pump is probably the installation you'd want, and it can provide cooling as well as Chicago can have very hot summers. (A geothermal heat pump installation may also be viable where you live.) For cooking, there are growing health concerns over gas stoves that will probably lead to increased regulations on stoves and range hoods (the overhead fans) -- this might require significant new installation in future (possibly a new chimney, if your existing range hood does not vent outside) to make your house increasingly attractive with a gas stove. In terms of a net cost calculation, it'd be complex, and a local consultant may have more insight into the regulations if there's significant money on the table. SamuelRiv (talk) 17:37, 1 April 2024 (UTC)

One more note: Induction stoves, which are electric, are more efficient than basic electic stoves. They reach cooking heat faster (and cool down faster). They use less electricity to maintain cooking heat. So, if you are redoing everything, you might as well get an induction stove. New ones are designed to blend into the counter so it is a counter-top when you aren't using it as a stove. 75.136.148.8 (talk) 17:41, 1 April 2024 (UTC)

To clarify my comment relative to yours, OP: the cost-efficiency-environment calculation for residential heating+cooling in Chicago, which has cold winters, is going to be entirely different than for the subtropical dry (southern) California or wet Florida. So -- and this should not be considered my advice in general -- ignore your mother. SamuelRiv (talk) 17:47, 1 April 2024 (UTC)

The fellow that makes Technology Connections videos on YouTube is from the Chicago area and he's made multiple videos about electrification, switching to heat pumps, and the like. Here's a recent video on the topic. While anyone can make a YouTube video on anything, I think you'll find these well-researched and easy to follow. Matt Deres (talk) 17:57, 2 April 2024 (UTC)

Since gravity is not a proper force, is there any proper force able to accelerate a system that consists of two identical photons moving in opposite directions [in a vacuum]?

If there isn't such a force, then what's the practical meaning of ascribing a finite positive mass [in a vacuum] to such a system, to which such a mass is really ascribed by Relativity theory? 147.235.210.126 (talk) 19:53, 1 April 2024 (UTC)

Photons can couple with matter. See Two-photon physics. Modocc (talk) 22:18, 1 April 2024 (UTC)

When I asked what the practical meaning of a two photon system's mass was, I actually asked if there was any proper force able to accelerate a two photon system, because according to Newton's second law (f=ma) the practical meaning of a given system's mass is the system's resistence to acceleration caused by a proper force, i.e. by a force able to accelerate the system by an acceleration dependent on the system's mass. 147.235.210.126 (talk) 03:56, 2 April 2024 (UTC)

When you apply Newton's laws to a system of photons, don't expect to get meaningful results. We could find a way to define the mass of a system of photons, but what makes you think it has a practical meaning? PiusImpavidus (talk) 09:59, 2 April 2024 (UTC)

I'm not interested in definitions having no practical meaning. But if you state that a two photon system's mass has no practical meaning, then I accpet it as a possible answer to my question. 147.235.210.126 (talk) 10:31, 2 April 2024 (UTC)

If you think gravity is not a force, try jumping off a building sometime. ←Baseball Bugs ^{What's up, Doc?} carrots→ 00:39, 2 April 2024 (UTC)

I didn't say that gravity was not a force, but that it was not a proper force, i.e. that the acceleration caused by gravity did not depend on the mass of the body being accelerated by gravity.

With regard to your suggestion: We won't jump off, because we want to avoid the gravitational acceleration, actually caused by the proper gravitational curvature, rather than by any proper force. i.e. by any force causing an acceleration that depends on the mass of the body being accelerated by that force.

Actually, I asked what the practical meaning of a two photon system's mass was, bearing in mind that this mass can't be related to gravity, because gravity can't be a proper force, i.e. because any acceleraion caused by gravity does not depend on the mass of the body being accelerated by gravity. 147.235.210.126 (talk) 03:48, 2 April 2024 (UTC)

Technically, those two photons together have a finite mass (the energy-momentum relation for the two-photon system is $E^{2}-p^{2}c^{2}=m^{2}c^{4}$) , which means that the "center of mass" moves like a massive particle. This has little practical meaning because the two-photon system has little, maybe even no, practical interest. Its mass is a matter of principle, but little more than a theoretical curiosity. Of more practical interest is a photon gas, for instance the cosmic microwave background, which has (by the same principle) a gravitationally active mass density. --Wrongfilter (talk) 10:13, 2 April 2024 (UTC)

In General relativity, active masses do not really exist. What generates a given star's gravity is the star's energy and stress (by Einstein's tensor). The same is true for any photon gas. That said, we can still use the mass-energy equivalence for ascribing also a theoretical mass to any object having energy. However, my question was, if that theoretical mass had any practical meaning, i.e. if it was influenced by Newton's second law (F=ma). If your main claim is that this theoretical mass has "...no practical interest", then I accpet it as a possible answer to my question. 147.235.210.126 (talk) 10:29, 2 April 2024 (UTC)

See Compton scattering. Modocc (talk) 13:36, 2 April 2024 (UTC)

So what's the proper force giving the two photon system's mass its practical meaning? By "practical meaning", I mean any impact of Newton's senond law (F=ma) on that two photon system's mass. 147.235.210.126 (talk) 14:00, 2 April 2024 (UTC)

Every photon's energy certainly can impact and move matter. Examples include laser ablation and rocketry. Their emissions/collisions/absorption are electromagnetic radiations. In other words, they interact with charges thus it is the force of radiation pressure: radiation pressure force AKA the force of light. Also, the momentum carried by the scattered photon changes due to the reaction force due to the light's force, but I'm not aware of any specific name for it though. Modocc (talk) 15:03, 2 April 2024 (UTC)

Let's be more specific: Can a two photon system be accelerated, according to Newton's second law F=ma? If this system can be accelerated, then which proper force can accelerate this system? By "proper force" I mean any force that can accelerate the system by an acceleration dependent on the system's mass.

On the other hand, if you think this system cannot be accelarated, then let me ask you a more general question, regardless of that system: Let there be a body having a mass. Does this mass have any practical meaning, besided the body's ability to be accelerated by an acceleration dependent on the body's mass? 147.235.210.126 (talk) 16:59, 2 April 2024 (UTC)

Let two photons converge upon an ion/electron and are scattered, (in other words, they are accelerated). The photons' combined momentum will be altered depending on their energies as well the effective mass of the charge(s) they encountered. Accelerations, energies, momenta and masses are important in physics, especially when analyzing scattering problems. Modocc (talk) 17:18, 2 April 2024 (UTC)

When two elastic balls - having different masses and identical velocities - collide with a wall, the wall changes their velocity by changing its direction, so the wall accelerates them, right? However, the force exerted by the wall is not a proper force, because it [accelerates the balls by an accelearation which] doesn't depend on the different masses of those balls: That's why the new velocities of those balls after the elastic collision are still identical to one another, although the balls have different masses, right?

The same is true for the process of the scattering you've talked about: The impact of this collision between the photons and the electron does not reflect a proper force, because this impact would not have depended on any mass of the photons if they had been other particles having a non zero restmass.

My question has been, whether you can point at any proper force that can accelerate the two photon system. By "proper force" I mean any force that can accelerate the system by an acceleration dependent on the system's mass. This is not the case in the process of the scattering you've talked about. 147.235.210.126 (talk) 18:33, 2 April 2024 (UTC)

Their reaction forces per Newton's third law depends on the ball's masses. Photon scattering depends on their energies which is why a lot of matter is opaque to visible light but not x-rays. Modocc (talk) 19:15, 2 April 2024 (UTC)

What do you mean by "Their reaction forces per Newton's third law depends on the ball's masses"? Just to make sure I understood you well, let me repeat the thought-experiment: When two elastic balls - having different masses and identical velocities - collide with a wall, the wall changes their velocity by changing its direction, so the wall accelerates them, whereas the new velocities of those balls after the elastic collision are still identical to one another, although the balls have different masses, right? 147.235.210.126 (talk) 20:40, 2 April 2024 (UTC)

You stated "the force exerted by the wall is not a proper force, because it doesn't depend on the different masses of those balls". That is wrong because the reaction forces (Newton's 3rd law) are given by f=ma (Newton's 2nd law). Per Newton's laws of motion. I should have been more explicit. Modocc (talk) 20:44, 2 April 2024 (UTC)

Oh sorry for the mistake: I meant that the [normal] force exerted by the wall is not a proper force, because it [accelerates the balls by an accelearation which] doesn't depend on the different masses of those balls. Agree? 147.235.210.126 (talk) 21:35, 2 April 2024 (UTC)

In three-dimensions the normal force by the wall is the reactionary force component of the ball's applied force against it. That simplifies to what I said if the ball's entire momentum mv hits it directly (ignoring g of course) without glancing off in any other direction. For example, a heavy or more massive baseball conveys more force and energy than a sponge ball (when their velocities are equal). Modocc (talk) 22:01, 2 April 2024 (UTC)

Ok, so back to your response beginning with the word "Their" (i.e. the response before your previous one), I accept your first claim: "Their reaction forces per Newton's third law depends on the ball's masses".

On the other hand, I guess you accept my claim (don't you?): When two elastic baseballs - having different masses and identical velocities - collide with a wall, the wall changes their velocity by changing its direction, so the wall accelerates them, whereas the new velocities of those baseballs after the elastic collision are still identical to one another, although the baseballs have different masses". Right?

If you accept, I will refer also to your second claim (ibid.), which is actually more relevant to my original question, and which states: "Photon scattering depends on their energies which is why a lot of matter is opaque to visible light but not x-rays". 147.235.210.126 (talk) 08:29, 3 April 2024 (UTC)

Per energy conservation, the balls, having reversed their velocities, retain their speeds given that the energy and momentum imparted to the wall is negligible. Modocc (talk) 12:50, 3 April 2024 (UTC)

So we agree about Newton's third law, because I said "elastic" collision, which is actually the same idea expressed in your last word [regarding energy], because in every elastic collision with a wall - the energy and momentum imparted to the wall is zero - hence negligible.

Back to the Compton effect, and to your second claim (ibid.): "Photon scattering depends on their energies which is why a lot of matter is opaque to visible light but not x-rays": Let me remind you of my question to which you responded by that senetnce. So my question has been, whether you can point at any proper force that can accelerate the two photon system, i.e. if you can point at any force that can accelerate this system by an acceleration dependent on the system's mass. I guess you already guess what I mean by acceleration: A change in the vector of velocity, becasue this is what Newton meant in his third law F=ma, right? However, in the Compton effect, I don't see any force that accelerates any photon (or any multy photon system) by any acceleration dependent on the photon's mass (or on the multy photon system's mass), so I wonder how the Compton effect may answer my question mentioned above. 147.235.210.126 (talk) 15:44, 4 April 2024 (UTC)

Elastic collisions often transmit significant kinetic energy, for example see Newton's cradle, therefore the balls would lose significant energy and momentum to the wall if it wasn't massive and/or fixed to the ground which is. As for scattering (accelerating) photons and their combined inertial mass I already covered those topics in previous threads and above. See the articles on Inertial mass, Scattering, Compton scattering and Radiation pressure for details. Modocc (talk) 18:03, 4 April 2024 (UTC)

Maybe, by mistake, you've replaced "non-elastic" by "elastic"? In non-elastic collisions with a wall, a significant kinetic energy is really transmitted to the wall - as you've said, and usually becomes thermal energy. However, in absolute elastic collisions with a wall, no kinetic energy becomes thermal energy. Instead, at the moment the [elastic] baseball collides with the [elastic] wall - the [elastic] baseball behaves like an elastic spring - its kinetic energy becoming potential energy, but at the moment the baseball bounces back to the opposite direction - its potential energy becomes again the original kinetic energy - identical to what it was before the absolute elastic collision. The only physical property which does change is the baseball's momentum - because its direction changes, but this is because of the normal force exerted by the wall. However, the kinetic energy is conserved, as far as - the two stages - before/after the absolute elastic collision - are concerned.

Anyway, by mistake, I had inserted this issue of Newton's third law to our discussion about your original remark regarding the Compton effect, so I suggest we leave the issue of elastic collisions with a wall, and return to the Compton effect - you've suggested as an answer to my original question - about the practical meaning of a two photon system's mass. So, regarding this original issue, you claim you've covered it in other threads, but unfortunately I don't know where I can find them. You also give some links to articles in Wikipedia, including the article about the Compton effect, but AFAIK those articles contain no clue about any proper force that can accelerate a two photon system, i.e can change this system's vector of velocity by an acceleration dependent on the system's mass. 147.235.210.126 (talk) 07:50, 5 April 2024 (UTC)

With Newton's cradle there is no heat and one can select reference frames in which either their collision energies or velocities are the same if one likes. Inelastic collisions however involve a change in internal energy: heat. I was not referring to that. There are further resources for learning about scattering problems and I've outlined the basics. Modocc (talk) 08:39, 5 April 2024 (UTC)

Since you say now, that the energy of the balls in Newton's cradle is actually conserved, so I repeat my suggestion: Let's leave Newton's cradle, because it has nothing to do with our original discussion.

As for your last sentence: You claim you have only "outlined the basics" of the whole issue of scattering, but I still don't see how it has anything to do with my original question (about whether you can point at any proper force that can accelerate a two photon system, i.e can change this system's vector of velocity by an acceleration dependent on the system's mass). 147.235.210.126 (talk) 09:48, 5 April 2024 (UTC)

With the accelerations (changes in their propagating directions) that occur from scattering, the photons' frequencies, energies and the momentum they carry change too: because of Newton's third law and radiation pressure (force per area). So far so good? Two antiparallel photons may fly past each other undisturbed, but if matter is present they might head off in different directions (or be absorbed). Modocc (talk) 10:34, 5 April 2024 (UTC)

Does the new direction the photons have after the scattering, depend on the old energy the photons had before the scattering? 147.235.210.126 (talk) 11:14, 5 April 2024 (UTC)

Yes. That is why I mentioned x-rays. x-ray photons penetrate substances with less deviation than less energetic photons. Modocc (talk) 11:22, 5 April 2024 (UTC)

So every photon's radial acceleration depends on the photon's energy, according to the following rule about a photon's energy: the more energy, the less (radial) acceleration, right? So, this rule is analogous to Newton's second law about a body's mass: the more mass, the less (radial) acceleration, right?

If you accept, then do you think the Compton effect is sufficient for ascribing a (relativistic) mass to a photon? This will be contrary to what many physicists claim, that photons have no mass, even not a relativistic one. Actually, user:Trovature mentioned this dispute (in this thread). 147.235.210.126 (talk) 12:10, 5 April 2024 (UTC)

This is what he wrote in a previous discussion to your questions [1] Particle physicists that study them refer to all particles' "relativistic mass" as simply energy. The fact it is not reference frame invariant is a cause for confusion. Modocc (talk) 12:31, 5 April 2024 (UTC)

Yes, his response was given in another thread.

Anyway, relativistic mass (if it exists) depends on the reference frame, just like energy. That's why this sort of mass is labeled as "relativistic", so I don't see why it should be "a source of confusion" (as you call it). But let's leave this issue aside.

I would like to focus on the issue of scattering. Do you agree to the first paragraph of my previous response? 147.235.210.126 (talk) 12:54, 5 April 2024 (UTC)

I agree per Newton's laws it takes more force to increase a deflection of a more energetic particle. Modocc (talk) 13:16, 5 April 2024 (UTC)

So, as far as radial accelerations are concerned:

A given photon's energy behaves, as a body's mass does in Newton's second law: F=ma, right? 147.235.210.126 (talk) 13:30, 5 April 2024 (UTC)

For a proper force, yes. Modocc (talk) 14:00, 5 April 2024 (UTC)

So I wonder why some physicists avoid ascribing a mass to a photon carrying energy. At least a relativistic mass, which actually depends on the reference frame just as the energy does. 147.235.210.126 (talk) 14:19, 5 April 2024 (UTC)

In general, there is the term mass-energy, but the masses of particles are defined by invariant mass. Modocc (talk) 14:47, 5 April 2024 (UTC)

The equivalence is also between relativistic energy and relativistic mass, so I'm asking why those physicists avoid using the equivalence between relativistic energy and relativistic mass, as far as light is concerned, despite the analogy between the phenomenon of scattering and Newton's second law (F=ma). 147.235.210.126 (talk) 15:49, 5 April 2024 (UTC)

Physicists call the equivalent definitions energy. With respect to spacetime, masses and massless particles are not interchangeable. For instance, only massless particles have the vacuum light speed. BTW, I will be busy with other things for a few days. Modocc (talk) 16:31, 5 April 2024 (UTC)

Yes, I know there are several differences (not only the one you've mentioned), but I wondered why they were sufficient for totally ignoring the analogy between the phenomenon of scattering and Newton's second law (F=ma).

Anyway, following your last important remark that mentions the vacuum, I've noticed my original question should have only been asked about photons in vacuum - wherein the photon's speed is measured as C - and the direction of that speed can't be changed; In any other medium there may be forces by which the photon's speed will be measured as less than C - as a function of the photon's energy, and also the direction of that speed may be changed under those forces - as a function of the photon's energy, hence the forces responsible for the photon's acceleration (including any radial one) must be proper forces - according to Newton's secind law (F=ma) and the mass-energy equivalence, so actually I have no question about any medium other than a vacuum. That's why I've just added the words "in a vacuum" [in brackets] to the title. In other words, my original question is supposed to have nothing to do with the Compton effect, which only refers to a medium other than a vacuum.

Actually, my original question is as follows: In a vacuum, a single photon has no mass, not even a relativistic one - if we stick to what is usually accepted among a lot of physicists (as mentioned by user:Trovatore in another thread). However, those physicists do ascribe a finite positive mass to a two photon system, even in a vacuum. So my question is, what's the practical meaning of that mass - ascribed to a two photon system [in a vacuum] by those physicists, at least as far as Newton's second law (F=ma) is concerned, bearing in mind that gravity is not a proper force, i.e. the acceleration caused by gravity does not depend on the mass of the body accelerated by that force. Two editors suggested (whether explicitly or implicitly) that this mass had no practical meaning. I accept it as a possible answer to my original question, but I still wonder if it may have other possible answers. 147.235.210.126 (talk) 11:07, 7 April 2024 (UTC)