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Physics Travel Guide – Physics concepts explained in three levels of difficulty
- freetonik 7y agoInteresting. I am slowly building a computer science dictionary with a similar concept: three levels of difficulty https://cs.quickref.dev/ https://cs.quickref.dev/
- zeusly 7y agoThat's very cool!
- kumartarun 7y agoKeep doing. Good stuff. Subscribed your youtube channel as well.
- nobrains 7y agoGenerally very nice, but I did not find the 3 levels of difficulties. Where can I see them?
- tiniuclx 7y agoThey are the tabs just below the title of every subject.
- betageek 7y agoThis is really great, would love something like this for pure maths.
- abhijat 7y agoA few answers from when a similar question was asked last time https://news.ycombinator.com/item?id=16373386 https://news.ycombinator.com/item?id=16373386
- johndoe42377 7y agoSome of those articles are just a modern Tantra - no one is seriously trying to refute these models because lots of people have a comfortable, high social status living out of it, just like modern theologians or tibetologists - they know the mantras and it's current interpretations, and the question of "How real it is" is frowned upon. Generalisations aside (however valid and useful) most of this theoretical physics is nothing but a socially constructed models, agreed upon. And yes, I have read a few of Bohm's books before forming an opinion.
- mnky9800n 7y agoIs that you jonathan tooker?
- johndoe42377 7y agoBefore Hegel and his abstract bullshit, the main question of philosophy was "What is real", not what a mind can imagine. Similarly, the main question of physics used to be "how everything is", not how do we think everything might be. A map is not a territory, a model is not what is. It is that simple and infallible.
- Koshkin 7y ago> the main question of philosophy Well, philosophy is known to ask questions for which there are no answers. As to (theoretical) physics, I think we should look at it first and foremost as a computational tool (similar to applied mathematics) which is the way it has been since Newton, then it becomes clear that physics does indeed help understand "how everything is" - in the sense that it helps us predict the results of experiments, and I am not sure if it even makes sense to talk about a "higher level of understanding" than that. A map is definitely not a territory, but it can indeed be (and will always remain to be) both "true" and "false" to a certain degree; similarly, no one in their right mind would say that physics is, should, or can be equivalent to the reality (aspects of) which it merely reflects.
- abdullahkhalids 7y ago
- m4r35n357 7y agoNo Special or General Relativity - WTF? OK found them hidden away under "models" - WTF again?
- karlicoss 7y agoWikis are intrinsicly hard to organize in a hierarchy. There is a search though.
- m4r35n357 7y agoThat is how I found them, estranged from the other "theories" for some reason.
- evanb 7y agoGeneral relativity is (sort of) a classical field theory; it isn't crazy to put it under models, in the same way that QFT is under 'theory' but the standard model is under 'models'.
- spodek 7y agoAlmost nothing about experiments. Physics is an experimental science, based on observation of nature. Its treatments of experiments is as if they were mere side notes to the real thing. The Tools section might include something like a ruler, clock, or basic physical tools used to observe nature with.
- nabla9 7y agoI strongly disagree "Physics concepts explained" has no need to add anything about experiments. The focus of the site is learning concepts. Criticizing focused educational site for not being comprehensive enough is not valid.
- duckmysick 7y agoI strongly disagree. Experiencing concepts first-hand through experiments improves learning and understanding, excites curiosity, and teaches practices that can be used in other disciplines. I learned about many physics concepts with simple experiments in elementary school. They can certainly be extended and adapted for an adult audience.
- nabla9 7y agoWhat you say is true about learning physics. Not valid criticism against this site. It's not meant to be the only source for learning physics. It is focused reference site for concepts. Having focus and focusing on just one viewpoint is a good thing.
- pretendscholar 7y agoMight be a good idea to understand the concept in general and then take a look at the experiment to prove it.
- madhadron 7y agoHuh. The first thing I opened was Aharanov-Bohm which immediately describes an experimental setup.
- 7y ago
- SeanFerree 7y agoCool article!
- magv 7y agoFrom just glancing at a few articles, this site is a treasure trove of references to highly readable explanations on a variety of fairly advanced topics. In fact, just the links to Wilczek's grand unification overview [1], and Klauber's Student Friendly QFT book [2,3] made this site worth visiting for me. Resources that explain physics in (relatively) simple language without requiring books worth of prior knowledge seem to always be targeted at school-level physics; this one is different. Of course, this is no substitute for a university curriculum, but as a way to plug holes in one's understanding, the site seems genuinely high quality. [1] http://frankwilczek.com/Wilczek_Easy_Pieces/172_Unification_of_Couplings.pdf http://frankwilczek.com/Wilczek_Easy_Pieces/172_Unification_... [2] https://www.quantumfieldtheory.info/ https://www.quantumfieldtheory.info/ [3] ftp://srdconsulting.com/USB_BackUp/Data/Articles/QFT/StudentFriendlyQFT/
- mhh__ 7y agoI haven't read it in full but Klauber's book is supposedly loaded with errors and also (in my view) needs re-typesetting (it's written in word)
- monktastic1 7y agoI found this section confusing (emphasis mine): https://physicstravelguide.com/equations/schroedinger_equation#tab__concrete https://physicstravelguide.com/equations/schroedinger_equati... "This means that for all systems where the Hamiltonian does not explicitly depend on the time, we known (sic) immediately how the time-dependence of the total wave function Ψ(x,t) looks like (sic), namely: Ψ(x,t) = phi(t)ψ(x) = Ae^(−Et/ℏ)ψ(x). The only thing we then have to do is to solve the stationary Schrödinger equation Hψ(x) = Eψ(x)." It sounds like they're saying that all systems with a time-independent Hamiltonian are stationary, which is obviously wrong. This would have confused the hell out of me while learning QM, and dissuades me from learning more on this site. Have I misread? I can infer what they're trying to say from context and previous knowledge, but that's of little help for someone new.
- contravariant 7y agoYou have misread slightly I fear. Note that he says: >the stationary Schrödinger equation Hψ(x) = Eψ(x)." which is not the original Schrödinger equation, but a Schrödinger equation which is stationary and which forms part of the solution of the original Schrödinger equation.
- monktastic1 7y agoThanks. That's the context I was referring to. Reading the whole thing again twice more, I can still confidently say it would have confused me more than helped me when I was first learning.
- scythe 7y ago>Ψ(x,t) = phi(t)ψ(x) = Ae^(−Et/ℏ)ψ(x) This equation is missing a sum symbol, also it should be e^(-iEt/ℏ), where in the correct case the amplitude does not change. What you get is a sum of products of each occupied stationary state and a time-dependent phase. So the general solution looks like this: https://en.wikipedia.org/w/index.php?title=User:Scythe33/sandbox&oldid=948716529 https://en.wikipedia.org/w/index.php?title=User:Scythe33/san...
- 7y ago
- globuous 7y agoJust looking around, but this looks like a gold mine ! Definitely going to be my go to site when I'm bored ! I love how each concepts are explained at high school, college, and grad school levels !
- dang 7y agoA thread from 2018: https://news.ycombinator.com/item?id=16372454 https://news.ycombinator.com/item?id=16372454