Also see Gerard 't Hooft's site on how to become a good theoretical physicist (https://goodtheorist.science).
So you want to learn physics (2021)
161–170 of 170 posts
Re: So you want to learn physics (2021)
#162Earlier quoted context omitted.
I think this shows a lack of self-doubt, which can be deadly. Those problems acted as verification to yourself that you understood the theory and its application. If you truly understood the material, then the problems would be zero effort. However, if you struggled with them it's a signal that you don't know what you think you know.
As someone who had an a similar experience to whom you are replying to, this was definitely not the case. The problems were easy, but were not "zero effort". Even if it takes you only a few minutes to do the steps and show the work per problem, then that could still take you 30-60 minutes to complete the assignment. That was time I'd spend doing things I wanted to do (fun in the short term, a nightmare in the long te…
I think usually the easy problems are just the "burn-in" time to solidify understanding, but there's usually a couple hard problems that take way longer to work through and those will teach you the intuition. Doing simple calculation is different than being forced to conceptualize the entire path from starting information to system to evolution to result.
Re: So you want to learn physics (2021)
#163Earlier quoted context omitted.
You might be interested in Kip Thorne (of Gravitation fame) and Roger Blandford's book Modern Classical Physics , which is designed to cover the elements of non-quantum physics that are generally ignored in the first year PhD curriculum. Part headers: statistical physics; optics; elasticity; fluid dynamics; plasma physics; general relativity
Fluid dynamics was the most awful course I ever took. I still get nightmares of me failing my graduation because of Navier-Stocks equation
Are you sure you learned the correct equation, Navier-Stokes?
Re: So you want to learn physics (2021)
#164Is there a guide like this but for learning astronomy and/or astrophysics? I would love to learn more about astronomy, but I don't know where to start.
Re: So you want to learn physics (2021)
#165I took physics in high school and college. It's has, and always has been, my most difficult class and it's because I have the hardest time trying to solve physics problems. I may give this one a go!
Re: So you want to learn physics (2021)
#166Earlier quoted context omitted.
It used to pose as a difficulty for self leaners because they did not have access to assignments, exams and solutions unless they register for classes. Nowadays it's a lot easier when there are so many free materials from top school online. And stack exchange and reddit is available almost 24-7 if one ever has a question.
> It used to pose as a difficulty for self leaners because they did not have access to assignments, exams and solutions unless they register for classes. Many textbooks still employ the deplorable practice of not presenting the answer to all exercises at the end, unfortunately.
Yeah, but I think there is a teacher's edition we can grab online from somewhere?
Re: So you want to learn physics (2021)
#167A point that's rightfully emphasized by the author: > Solving problems is the only way to understand physics. There's no way around it. This generalizes well to other fields. I don't want to discourage anybody from trying to educate themselves in a difficult field (be it physics or something else), but that's a very common and immediately visible problem with autodidacts. If you haven't worked through enough hard pro…
I only became reasonably proficient in physics when I took the summer off between undergrad and graduate school and spent three months, six days a week, ten hours a day, doing nothing but working through four years of undergraduate physics curriculum by solving problems from my textbooks. There is no substitute for solving problems.
> There is no substitute for solving problems
But you will spend the rest of your life arguing with people who insist that there must be a ("quick and dirty") substitute and you're responsible for finding it.
Re: So you want to learn physics (2021)
#168This has the same omission that my undergrad program had: continuum mechanics. Even just the very basics (pressure, velocity, etc in a moving, non-equilibrium system) and translating between the terminology used by different science and engineering fields (static pressure, total pressure, velocity pressure, stagnation pressure, hydrostatic pressure, dynamic pressure, plain old pressure, head, oh my!) is very useful.…
I think solid state continuum mechanics are also the optimal place to introduce tensors. For some reason, the first tensors many physics students encounter are very abstract. It would be like if the first vectors you encountered were quantum mechanical states. Stress and strain are, in my opinion, the ideal "prototypical rank-2 tensors", and it's useful to spend time really elaborating what that means, the same way w…
That’s an interesting idea. The best class involving tensors I ever took was an introductory course on differential geometry, and I still think the coordinate-free approach of thinking of tensors as multilinear functions from some number of vectors to some other number of vectors (or a scalar) is great. Everything else just involves picking coordinates and figuring out where the numbers to :)
But I probably like abstractions like this more than most people.
Oddly, undergraduate physics also seems to be missing another, arguably even more fundamental, tensor: the moment of inertia. You can get quite far (in three dimensions, and only in three dimensions) by thinking of rotation as a vector. (Or a quaternion if that floats your boat.) But you can’t get very far by pretending that the moment of inertia is a scalar, and you get very confused very quickly if you treat it as three scalars in the magical coordinate system in which you can write it like that.
Re: So you want to learn physics (2021)
#169Earlier quoted context omitted.
> In another comment, you said that you don't know what the Navier-Stokes equations are. Given that, I don't think you're in a good position to judge their value. It was an exaggeration given that it never came up during my studies once. And I think that's a fantastic assessment of their value that I made it through most of a decade of studies without having to know a thing about fluid dynamics. > I have a couple of…
You are missing my main point. Physics education tends to exclude fluid dynamics, so of course you wouldn't hear much about it or do research in it if you only have physics degrees. If a physics degree were about physics as defined in the dictionary, fluid dynamics would be more prominent. But "physics" as studied in a "physics" department is much more narrow than the dictionary definition. Fluid phenomena is ubiquit…
Physics education focuses on exciting areas of research. There isn't much interesting work currently taking place in fluids. We consider it a solved problem. The fact that we drive cars through fluids is completely irrelevant.
Re: So you want to learn physics (2021)
#170Earlier quoted context omitted.
Like another commenter, I'm curious what drove you to this. Seems like clearly A Good Idea I Could Have Benefited From, but my attitude was always: I finished the class, whatever I need to learn through application, life will point me toward. Yet I wish I had done something similar to what you did. What gave you the impetus?
> I finished the class, whatever I need to learn through application, life will point me toward. In math/physics, it often won't. Solving lots of problems serves two particular purposes: To really solidify the concepts in your mind so you won't forget, and ensuring you learn the techniques and not just the knowledge. For the former, you may find yourself in the position where you find yourself way over your head, and…
This is really interesting perspective -- thanks for sharing it. I think there's something to the idea that some fields are more 'binary' than others -- that if you can't make it past some threshold of _true understanding_ that you will be denied experiences that could push that threshold further. Such a field would warrant a different strategy for learning / mastery than a less binary field.
I'm going to ruminate on this.