Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

So you want to learn physics (2021)

susanrigetti.com

Post reply on HN
Print view View original

31–40 of 170 posts

Re: So you want to learn physics (2021)

#31

Post by btrettel »

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've noticed before that "physics" as in what is taught for a physics degree has gaps which make little sense to me as a mechanical engineer. Continuum mechanics (including both fluid and solid mechanics) is unfortunately nearly entirely absent aside from some basic things like Hooke's law and Bernoulli's principle.

In my view, what's taught for a physics degree is more of a historical accident than a selection of the most important principles. In an extraterrestrial civilization, the boundaries between engineering, physics, and chemistry may be entirely different.

Dismissing Navier-Stokes as just a consequence of Newton's laws and thus unimportant can be extended further towards dismissing a large fraction of what's taught in physics degree programs. An undergraduate physics student may get more education on Bose-Einstein condensates (which are just a consequence of quantum mechanics :-) than they do on Navier-Stokes. The Navier-Stokes equations are a lot more important than Bose-Einstein condensates in my view.

Re: So you want to learn physics (2021)

#32

Post by ghaff »

deepsquirrelnet wrote: post #28

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 calcul…

One problem with approaching physics without any calculus is that you're more or less in the place in which most people taking high school physics are. Here are a bunch of formulas. Memorize them and don't worry about why they are what they are or how they relate to all the other formulas that you also have to memorize.

Re: So you want to learn physics (2021)

#33

Post by _dain_ »

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.

>can you tell me if you can really get a physics degree without bumping into Bernoulli or Navier-Stokes?

Bernoulli principle was covered in my bachelor degree but Navier Stokes wasn't; true-blue fluid dynamics was either an optional course that I didn't take or a grad student course, I don't remember now.

Re: So you want to learn physics (2021)

#34

Post by elashri »

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.

There is a more practical reason for that. QFT has become essential to learn for many Condensed matter physicists. And they always are with particle physicists which will span most of the physics community, at least comparing with whose work involve in-depth knowledge of fluid mechanics. Not to mention that QFT seems easy in comparison.

Re: So you want to learn physics (2021)

#35

Post by ChuckMcM »

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…

Totally 100% with this. When younger I thought I could read the material and say "Oh, okay that makes sense I understand this." Only to fail miserably when on a test or somewhere I had to apply what I "knew" and realizing I didn't actually know it. I lean strongly toward autodidacticism and learned that if I could solve problems with the technique then I knew it.

Re: So you want to learn physics (2021)

#36

Post by libraryofbabel »

cb321 wrote: post #30

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 experie…

It will be impossible to learn physics from this book, even in the unlikely event that you already have all the requisite mathematical background (partial differential equations, vector calculus, tensors, etc.). Degree of “ambition” doesn’t come into it; you just can’t start out with special and general relativity and spacetime and quantum fields; you need to solve a lot of problems in newtonian mechanics and electromagnetism and thermodynamics and get a solid foundation in classical physics first. There is no royal road to this stuff: Susan’s list lays out the standard curriculum and it’s really the only way we know to produce physicists.

That said, this book does look like a great text for someone with a graduate level physics knowledge who wants to refresh their memory.

Re: So you want to learn physics (2021)

#37

Post by bluish29 »

> Classical Electrodynamics by Jackson (essential). This is the bible of classical electrodynamics, and everyone who works through either loves it or hates it (I loved it).

I agree that there is a division between who loves that book (like the author) and the majority of the graduate students who had nightmares (and sometimes still gets). I like this goodreads review of the book [1]

> A soul crushing technical manual written by a sadist that has served as the right of passage for physics PhDs since the dawn of time. Every single one of my professors studied this book, and every single one of them hates it with a passion. While I've no intention of becoming a professor, I still wonder, will my colleagues also inflict this torture on their students? Will the cycle be perpetuated ad infinitum? How many more aspiring physicists will we leave battered and bruised at the gates of insanity before switching to a textbook that seeks to make electrodynamics clear and intuitive rather than a mind-numbing trip through the seventh circle of hell?

[1] https://www.goodreads.com/review/show/1266180525

* personal note: If this book is really the bible of classical mechanics, then I'm atheist.

Re: So you want to learn physics (2021)

#38

Post by libraryofbabel »

bluish29 wrote: post #37

> Classical Electrodynamics by Jackson (essential). This is the bible of classical electrodynamics, and everyone who works through either loves it or hates it (I loved it). I agree that there is a division between who loves that book (like the author) and the majority of the graduate students who had nightmares (and sometimes still gets). I like this goodreads review of the book [1] > A soul crushing technical manual…

Well yes, but curious what book you would recommend instead for graduate electrodynamics? Note that she already recommends first studying Griffith's Introduction to Electrodynamics at the undergraduate level (and that one is a true pleasure to read imho).

Re: So you want to learn physics (2021)

#39

Post by civilitty »

belugacat wrote: post #22
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…

> 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.

That mirrors the trajectory of all humankind, doesn’t it? From lofty Platonic ideals to nitty gritty empiricism and experimentation.

Re: So you want to learn physics (2021)

#40

Post by ak_111 »

BenFranklin100 wrote: post #26
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.

That is some dedication, well done. Interesting to know more about your career and where this lead to if you continued down the physics path.
Post reply on HN