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

Re: So you want to learn physics (second edition, 2021)

#71

Post by havercosine » Tue, Jul 14, 2026, 3:28 PM UTC

In case if any Physics learner finds this useful: Susan Rigetti's list is great if you are planning to do a late life PhD in Physics but not if you are re-learning it on the sideline of normal career as a hobby.

I've found many hard-core Physics textbooks to be off putting. Because the syllabus and its progression makes it seems like we are jumping from one special formula to another and there's just so much to learn! I was trying to search for a physics book that will try to cover as much ground as possible in fewer ideas and mental models. Roughly similar to Elon's idea that knowledge is a semantic tree and one should focus on trunk and big branches first.

Thomas A Moore did this experimental syllabus / series called "six ideas that shaped Physics". Each textbook takes one idea like "conservation laws constrain interactions". It's an excellent series, each book is relatively short and has amazing explanation. Especially look out for 2nd edition because later editions were probably "mainstreamed" by editors / publishers. The series is great choice for self learners. It uses non-standard notation and terminology at places to get the point across effectively so maybe not a great textbook lol.

2 standout examples for me : the first unit starts from the idea of interactions -> change in momentum -> to talk about change in kinetic energy. This motivates the idea of work done from first principles instead of directly throwing a definition "force . displacement". The unit on electromagnetic fields similarly has a beautiful discussion to motivate why one would use the ideas of curl and divergence.

Re: So you want to learn physics (second edition, 2021)

#72

Post by pmontra » Thu, Jul 16, 2026, 8:59 AM UTC

Ono-Sendai wrote: post #70

pmontra wrote: post #55

Earlier quoted context omitted.

This is new to me (thanks, I'll investigate) and it's the kind of things the books of Physics at University (Computer Science) was full of, completely detached from real world experience. Then there was the book of exercises to prepare for the exams. Sometimes finding the right way to go from theory to calculations was a puzzle in its own. I guess that they were almost the very same books they used at the Physics dep…

Are you saying my statement is very abstract? or down to earth?

I break it down in reverse order to let you understand how I get a gist of that definition

wavefunction, for example light or any particle, this can't be argued.

the complex plane, because? But a complex number is only a pair of numbers and I know that in polar notation it's handy for:

rotation! And I remember that the electric and magnetic components are on orthogonal planes so we are back to complex numbers and maybe the components rotate, but how about neutral particles? But they are not neutral inside. I think that I'm already off track, very lost.

Energy = frequency, because I know that higher frequency photons are more energetic.

Finally, usually we learn about kinetic energy, then E = mc^2 and maybe about the relativistic effects, without the formula. Those things can be understood easily and are taught at school. The jump to angular rotation and the complex plane is something that few people are exposed to and, as I hope to have demonstrated, it's not easy to map to common experiences, which could be inevitable.

Re: So you want to learn physics (second edition, 2021)

#73

Post by Ono-Sendai » Mon, Jul 20, 2026, 12:56 PM UTC

pmontra wrote: post #72

Ono-Sendai wrote: post #70

Earlier quoted context omitted.

Are you saying my statement is very abstract? or down to earth?

I break it down in reverse order to let you understand how I get a gist of that definition wavefunction, for example light or any particle, this can't be argued. the complex plane, because? But a complex number is only a pair of numbers and I know that in polar notation it's handy for: rotation! And I remember that the electric and magnetic components are on orthogonal planes so we are back to complex numbers and may…

Hi, fair enough. I've thoroughly immersed myself in this stuff enough that I sometimes don't realise people aren't as familiar with the concepts and jargon. I'm going to write another article that I think should help about the Klein gordon equation, at some point.

See my last article here https://forwardscattering.org/page/Intuitive%20Quantum%20Ele... Although it is a bit technical. next one will start simpler.