So you want to learn physics (2021) • Hacker News Board

Re: So you want to learn physics (2021)

#21

Post by jwuphysics » Sun, Aug 20, 2023, 6:55 PM UTC

elashri wrote: post #15

kingkongjaffa wrote: post #13

It’s a decent list but thermodynamics is introduced way too late in the list (after modern and quantum wtf) and fluid dynamics and fluid mechanics including aerodynamics is entirely missing. If you have a physics education (I have an engineering education) can you tell me if you can really get a physics degree without bumping into Bernoulli or Navier-Stokes? At least just to see the lay of the land.

I am writing my physics PhD thesis and I did not study fluid mechanics (other than the few chapters in the standard general physics). It will really be dependent on what is your physics field but you can definitely survive in physics without deep knowledge of fluid mechanics except when your study require it PS: I am a particle physicist.

A professor remarked that it was a bit sad that physics students nowadays have a better understanding of quantum field theory than fluid mechanics. He mentioned this while lecturing on QFT.

Re: So you want to learn physics (2021)

#22

Post by belugacat » Sun, Aug 20, 2023, 6:55 PM UTC

qsort wrote: post #3

A 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…

That’s a POV I’ve grown to adopt as I got older (like many, perhaps). I used to heavily privilege theory, believing that everything could (and maybe should) be derived from first principles.

Now I place the concrete over everything else; theory is nice when it can illuminate why the practice works. Otherwise, it’s just words.

The most frustrating is when I have friends who have derived their entire understanding of a subject I know as a practitioner (typically something tech/programming related) from watching YouTube videos/listening to podcasts.

Because they’ve heard hours and hours from experts, they have a feeling of deep understanding. But talking to them about this topic is extremely frustrating because their knowledge clearly has never had to be applied to the real world, and is grounded in nothingness, so they misunderstand lots, but they feel like they know what they’re talking about as much as you do.

Re: So you want to learn physics (2021)

#23

Post by carabiner » Sun, Aug 20, 2023, 6:56 PM UTC

kingkongjaffa wrote: post #13

It’s a decent list but thermodynamics is introduced way too late in the list (after modern and quantum wtf) and fluid dynamics and fluid mechanics including aerodynamics is entirely missing. If you have a physics education (I have an engineering education) can you tell me if you can really get a physics degree without bumping into Bernoulli or Navier-Stokes? At least just to see the lay of the land.

NS is too applied and seems akin to including the beam equation.

Re: So you want to learn physics (2021)

#24

Post by javajosh » Sun, Aug 20, 2023, 6:59 PM UTC

qsort wrote: post #3

A 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…

Yes, and I'd take it further. What I'd like to see more of in physics texts is presenting a problem before offering the solution. Too often you get what amounts to a laundry list of techniques and ideas, which are the components to the answers to hard problems, but the student isn't motivated to learn them. If you present the hard problem first, the student may flail around and realize: I need something to help with this! Now that they know they need it, and why, you can give them the tool that fits the bill. For example, I think calculus is probably better learned after trying to write down some force laws, and perhaps doing some numerical analysis. Then when you learn them you realize those nice closed-form solutions aren't busywork, they are huge labor saving tools that eliminate ad hoc labor intensive analysis.

I would also deemphasize the more mathy parts of calculus - do you really need a deep dive into continuity or the fundamental theorem of calculus? Eventually, yes. But it's just like programming: you're not going to need to understand language theory or ADTs or category theory or lambda calculus to write your first program. Or your second. And, IMHO, you should only reach for this understanding when you realize you need it. Otherwise, it won't integrate well into your toolkit.

Re: So you want to learn physics (2021)

#25

Post by [deleted] » Sun, Aug 20, 2023, 6:59 PM UTC

jwuphysics wrote: post #21

elashri wrote: post #15

Earlier quoted context omitted.

I am writing my physics PhD thesis and I did not study fluid mechanics (other than the few chapters in the standard general physics). It will really be dependent on what is your physics field but you can definitely survive in physics without deep knowledge of fluid mechanics except when your study require it PS: I am a particle physicist.

A professor remarked that it was a bit sad that physics students nowadays have a better understanding of quantum field theory than fluid mechanics. He mentioned this while lecturing on QFT.

[deleted]

Re: So you want to learn physics (2021)

#26

Post by BenFranklin100 » Sun, Aug 20, 2023, 7:00 PM UTC

qsort wrote: post #3

A 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.

Re: So you want to learn physics (2021)

#27

Post by tekla » Sun, Aug 20, 2023, 7:00 PM UTC

jwuphysics wrote: post #21

elashri wrote: post #15

Earlier quoted context omitted.

I am writing my physics PhD thesis and I did not study fluid mechanics (other than the few chapters in the standard general physics). It will really be dependent on what is your physics field but you can definitely survive in physics without deep knowledge of fluid mechanics except when your study require it PS: I am a particle physicist.

A professor remarked that it was a bit sad that physics students nowadays have a better understanding of quantum field theory than fluid mechanics. He mentioned this while lecturing on QFT.

But fluid mechanics is haarrddddd (Aeronautical Engineer). Compressible fluids can go suck it. I rue the day Navier-Stokes became a thing.

Re: So you want to learn physics (2021)

#28

Post by deepsquirrelnet » Sun, Aug 20, 2023, 7:01 PM UTC

Even though Susan Rigetti says you don’t need to learn calculus first, I would recommend it -— or learn it concurrently with the introductory mechanics course. Mechanics is so much more enriching when you learn the mathematical language that was created to describe it.

You’ll already be one step ahead by the time you get to the second course, which is good, because you can strongly benefit from learning vector calculus at that time. I really enjoyed the text “Div, Grad, Curl and all that”.

Re: So you want to learn physics (2021)

#29

Post by monster_group » Sun, Aug 20, 2023, 7:02 PM UTC

fcatalan wrote: post #10

I dropped out of Physics back in the day, because I loved computers a bit more, and now that I'm kind of fed up with computers I'd like to remove the thorn and do something like this. But I find that so much time has passed that I would need to brush up parts of my high school maths first, and this kind of discourages me before even starting.

I decided to start self learning theoretical physics late last year. I have been now studying physics every day for almost a year (before and after work). I did have to brush up on calculus and matrices but it came back very quickly (within a few days) after a 25 year gap so I'd say don't let that discourage you.

Re: So you want to learn physics (2021)

#30

Post by cb321 » Sun, Aug 20, 2023, 7:04 PM UTC

Rather than 27 (or however many) books, an ambitious student may be able to use just one big-ish book: Ian D. Lawrie's "A Unified Grand Tour Of Theoretical Physics". This even has a little 18 page "Snapshots of the Tour" which might be a trip down memory lane for those who studied physics long ago.

Of course, it might also be impenetrable if you haven't had prior exposure to most of the material.. I have zero experience trying to teach physics from it.