Really dumb question - Page 1
Forum section: electronics / general

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: August 04, 2023, 02:51:53 am
content: Usually we are told that electrons "orbit" the nucleus. Like electrons are particles that move in 3D paths.Isn't that a persistent current?Is space a superconductor? As long as there's strain in the fabric from the positive nucleus?I don't get it.I'm probably being what The Great Gazoo would call a dumdum.

author: ataradov
author_rank: Super Contributor
timestamp: August 04, 2023, 03:05:14 am
content: You are usually also told that this is a simplified model at the same time.This is the easiest way to introduce the atom model to kids. And in recent years it actually gets more and more push back, since there are a lot of holes in the model if you assume that involved particles are macroscopic objects. But you cant just throw a bunch of quantum physics at 8th graders.

author: vad
author_rank: Frequent Contributor
timestamp: August 04, 2023, 04:19:56 am
content: There is the electric current. In quantum mechanics, electric current from a charged particle can be defined as the particle's electric charge (e) times the probability current of the wavefunction (j).Let's take the example of the simplest atom - hydrogen. Skipping boring math, the electron in a hydrogen atom exhibits a nonzero probability current j along the azimuth dimension in spherical coordinates, resulting in a rotating current. Interestingly, it doesn't matter how you orient the spherical coordinates in our 3D world, whether it's bottom up, upside down, left to right, or aligned with the vector from the center of Earth to let’s say Sydney Opera; there will always be a current along the "equator", and zero current along radial and zenith dimensions of the spherical coordinates.

author: IanB
author_rank: Super Contributor
timestamp: August 04, 2023, 04:42:21 am
content: Quote from: Alex Eisenhut on August 04, 2023, 02:51:53 amThe problem with a model of charged particles like electrons orbiting a nucleus is that the charged particles by following a circular path would be under constant acceleration, which means they would be radiating energy. Since atoms at rest do not radiate energy, the charged particle model cannot be correct.On the other hand, atoms do exhibit magnetic properties, which means there must be an electric current involved (magnetic fields are generated by electric currents). However, the existence of such an electric current does not permit one to say that space is a superconductor. Resistance to electric current is a macroscopic phenomenon. There is no such thing as "resistance" at the quantum scale.

author: SiliconWizard
author_rank: Super Contributor
timestamp: August 04, 2023, 09:56:54 pm
content: That's not really a dumb question. More like a really unanswered one if we dig a little deeper.There have been threads with tens of pages already on topics related to this, and I don't think we ever came up with anything "conclusive".

author: TimFox
author_rank: Super Contributor
timestamp: August 04, 2023, 10:26:51 pm
content: The "planetary" model of electron orbits was soon rejected, due to the acceleration discussed above that would radiate all the energy away.The previous model was the "plum pudding model" with electrons surrounded by a volume of positive charge, like negatively charged "plums" embedded in a positively charged "pudding".When quantum mechanics evolved, atomic spectroscopy required that electrons have discrete values of orbital and spin angular momentum, along with "shells" of different energy levels.This is not a classical model, and the explanation of the quantum model of the atom can be found "as clerkes fyndyn wretyn in here book."Even if you find this model difficult to understand and don't like it, it works extremely well in quantitative detail to calculate atomic spectra, which result from the energy differences between "allowed" transitions between states.A typical state identification is 1s or 2p: see illustrations of the electron density of such "orbitals" inhttps://chem.libretexts.org/Bookshelves/Organic_Chemistry/Organic_Chemistry_(Morsch_et_al.)/01%3A_Structure_and_Bonding/1.02%3A_Atomic_Structure_-_OrbitalsMore than you want to know about this is in the classichttps://www.govinfo.gov/content/pkg/GOVPUB-C13-e582a49ca4d383aba1df8cb2df047e09/pdf/GOVPUB-C13-e582a49ca4d383aba1df8cb2df047e09.pdf

author: ataradov
author_rank: Super Contributor
timestamp: August 04, 2023, 10:37:08 pm
content: There are a lot of things that planetary model does not get right. There are all sorts of corrections that make some of the stuff work, but they make things much more complicated.Just like plum pudding is taught to be obsolete, planetary model should also be included there. Orbitals is definitely the way to go. Although you do abandon intuitive understanding and just have to accept a bunch of rules. But the rule set is fairly limited.

author: EPAIII
author_rank: Super Contributor
timestamp: August 10, 2023, 08:03:56 am
content: A really dumb question! Well, by asking really dumb questions, the greatest minds in science have made the greatest advances. No joke. That is for real. That is how it happens.As others have said, electrons can't actually orbit or circle the nucleus. If they did, all their energy would quickly radiate away.Quantum mechanics seems to say that an electron is described by what is called a wave function which assigns to every pointin the entire universea probability of finding that electron at that point. The electron can not be said to actually be at any of those points with complete certainty, although it is a lot more likely to be near that atom than across the universe in a distant galaxy. But both those locations and ALL others are possible: there really is a very small possibility that it really is in one of those distant galaxies. It is only when we devise a means of observing it's position that the wave function is said to "collapse" to a single point or small area where the electron then "decides" to be observed. It does not rotate in any orbit. It does not move from point to point in any manner. It only has a probability of being found at each point when we cause the wave function to "collapse" by actually observing it's position. In a way, it is the act of observing that causes it to have a specific location; otherwise it really does not.Now, if you find that hard to understand, you are not alone. I find it hard to understand. Physicists find it hard to understand. People like Einstein and Hawking found it hard to understand. And they spent hours, days, weeks, and years asking really dumb questions about it. Einstein was said to have said that "God does not play dice with the Universe". Steven Hawking is said to have responded that "Not only does God play dice, but He sometimes throws them where they can not be seen." Two great minds and two completely different views as to how the universe works. And I suspect that newer views will come along showing both of them to be at least somewhat if not completely incorrect.And that is the real nature of science. Different views. Different theories. Discussion about those theories. Dumb questions asked about them. Experiments are devised to make observations. And then new views. New theories. Science is NEVER settled. And those who say it is are the real dummies. That's a very, VERY,VERYimportant concept: science is NEVER settled.Never!In the end it is the dumbest questions, perhaps I should say the simplest questions that produce the most remarkable results. So, keep asking them.Quote from: Alex Eisenhut on August 04, 2023, 02:51:53 am

author: vad
author_rank: Frequent Contributor
timestamp: August 12, 2023, 05:09:47 am
content: Quote from: EPAIII on August 10, 2023, 08:03:56 amThis is an oversimplification. Electrons in atoms do possess momentum and thus exhibit movement, albeit not in a classical sense. For instance, in a hydrogen atom, the electron's magnetic dipole moment arises from both the orbital motion and spin.In the realm of quantum physics, specifically quantum electrodynamics, electrons are depicted as wavelets of the electron field, which is one of the few fundamental quantum fields. The wavelet's position is defined by the wavefunction, and its dynamics follows Schrodinger's equation. The wavefunction of the electron in a hydrogen atom is not static; the wavefunction itself “flows” and the measure of this flow is called “probability flow”.Edit: no matter from which angle you observe the hydrogen atom, you would consistently measure its magnetic dipole moment aligned either parallel or antiparallel to the axis of measurement. Consequently, it would seem as though the electron is always "orbiting" and "spinning" within a plane perpendicular to the measurement axis, no matter the direction of the axis.