
So You Want to Learn Physics (2016) - apsec112
https://www.susanjfowler.com/blog/2016/8/13/so-you-want-to-learn-physics
======
bollu
I like the list! It's very "physics person" oriented. Unfortunately, I have
faced an insane amount of frustration trying to learn from the same sources
because they "skip" on mathematical detail, often leading to more confusion
down the line. I personally enjoyed the books I write down below to learn
"rigorous physics":

\- Classical mehhanics by VI Arnold: We first abstract define what "space" is,
analyze its properties, then move on to build Lagrangian and Hamiltonian
formalisms. Is a great book to understand formally (i) what we mean by
"observer" in classical mechanics, (ii) variational problems, (iii) the
precise relationships between the Lagrangian and the Hamiltonian

\- Wald + Misner Thorne Wheeler for general relativity. MTW is the "bible",
with great pictorial explanations for everything. Wald prefers to write
everything in terms of differential geometric language which makes for an
entertaining read. For example, he does not write "the particle is at rest".
Rather, he writes "the particle is invariant under time-translational
symmetry". It was eye-opening to learn how to "think like a geometer" about
these sorts of ideas.

There is also Leonard Susskind's video lectures called as "the theoretical
minimum" where he explains, rigorously, classical/quantum/GR/QM/stat-mech:
[https://theoreticalminimum.com/courses](https://theoreticalminimum.com/courses).
I've personally watched the GR lectures and found them very informative.

Finally, there is Landau and and Lipschitz: These are dense, terse, often
difficult, but honestly, written with extreme clarity. This was the only
undergrad stat-mech book I could find which actually formally defines the
phase space, the averaging procedure we use, etc.

~~~
crispyambulance
I think all undergrad STEM programs should put A LOT MORE emphasis on
mathematics and other fundamentals before bothering with heavy
specializations.

The Arnold book is great, but it presumes a level of mathematical
sophistication that isn't practical to achieve (at least in the US) until well
into graduate school, and realistically?, only for Physics theory students or
some Math students that are motivated to dive into Physics.

~~~
prionassembly
There are major theorems in the famous "Calculus on Manifolds" by Spivak that
are exercises (and not end-of-chapter or starred exercises either) in Arnold.

------
dschuetz
"Everyone can learn physics" is a flat out lie to make other people feel
better. Without a proper tutorium and insufferable fits of frustration it's
only possible to learn such complex subjects on your own you if have the right
mind (whatever that is) for it. That arrogance some people have saying "If I
can do it, why can't you?!" is beyond tolerable.

The knowledge transfer process is different for every person, because people
learn things differently. The school doesn't teach you HOW to learn, only WHAT
you are supposed to know to be a productive member of society with some value
to companies. More inquisitive minds go to sciences and engineering, only to
discover that universities are just a next level of schooling. Only people
aiming for PhD learn how to do "independent" research, only to discover that
research paper business is dirty.

The article only lists books and what the author thinks about them. It doesn't
say how to learn physics. Also, learning physics without experiments is as
valuable as learning to drive without ever getting in the actual car.

~~~
wegs
Everyone can learn!

The problem is many people don't know how to learn, or haven't developed good
habits-of-mind. That goes under the terms executive function and metacognitive
skills. They are force multipliers throughout your education, and you're right
that schools don't teach them.

If I can do it, so can you! It just takes a few years developing those skills,
and ideally a little bit of mentorship to point you on the way.

And no, people don't learn differently. That's one of the biggest lies fleeced
upon us. The reference there is: "Learning Styles: Concepts and Evidence."
Turns out we all learn more-or-less the same way. Many of us believe we learn
differently, but we actually don't. A big part of executive function is
differentiating between activities which /feel/ like learning, and ones where
skills actually grow.

~~~
leadingthenet
The arrogance displayed here by saying “If I can do it, so can you!” when
that’s exactly what OP is complaining about is astounding.

Does everyone have the same level of intelligence? Are you really telling me
that absolutely any member of the public could learn QFT, even people with a
severe learning disability and low-IQ? Anyone you just randomly plucked off
the street? Just no.

~~~
yummypaint
As a practicing physicist, i would compare the amount of time, effort and
skill needed to complete a PhD to that needed to become a professional session
musician. Some people will find aspects of it much easier than others because
of talent, some will get a big head start in childhood, some will learn much
faster than their peers because they practice 6 hours per day and are driven
by their passion. Some people get lucky and have the trifecta.

This doesn't mean that there isn't value in an adult choosing to learn an
instrument (i.e. study physics). It can be enriching even if one never reaches
the point of quitting their day job to play music full time.

~~~
leadingthenet
Apologies if I came off as needlessly combative, my phrasing could certainly
be improved.

Don’t get me wrong, I completely agree with what you’re saying. In fact, I
encourage anyone with even the slightest inclination to study essentially
anything, but especially physics, in their own free time to do it. You’re spot
on in saying that there’s value in doing that.

The only assumption I wanted to challenge was that absolutely every human on
Earth could do it. I just think that’s patently untrue, and betrays an
inability to view things from other people’s perspective.

------
spodek
I earned my PhD in physics at Penn and Columbia, helping build a satellite
still taking data (XMM-Newton). I love physics. I loved learning physics.

Physics is not math. It is an experimental field. Ctrl-f _experiment_ yields
no results on that page. Ctrl-f _lab_ shows only results in the comments. I
love that that page exists, but it's missing the physical component of
physics. Learning only theory may serve many people, but it doesn't serve the
field.

Now that I teach project-based learning, albeit in leadership not physics, I
see huge gaps in my physics education about experiment, curiosity, doing
things with our hands, realizing we can test things ourselves. Most lab
classes I took walked us through known results so we could write the data we
were supposed to find if we measured wrong -- the opposite of science.

If you want to be a theorist, great, but distancing physics from what anyone
can _do_ seems to make it less accessible.

For example, I work on sustainability. People routinely seem shocked that
their turning on a light switch or air conditioner necessarily today means
somewhere some power plant had to convert that energy from something else,
polluting in the process.

~~~
mindcrime
_Physics is not math. It is an experimental field._

Isn't this kinda what Sabine Hossenfelder has been saying for the past couple
of years?

But that itself seems to be a reaction to the way so much of physics _has_
become "just math". One can bemoan this state of affairs (and people have,
obviously. Hossenfelder, Peter Woit, Lee Smolin, etc.), but it seems like
that's kinda where we're at these days... at least for a large portion of the
physics community.

~~~
lambdatronics
There's plenty of experimental physics, but everyone seems to think physics
means theoretical particle physics. It bugs me.

------
sampo
I have found that there is a world of everyday physics, related to things like
temperature, humidity, weather, materials (durability, permeability etc.),
clothing, nature, cooking, farming, cars, and also now in covid times about
droplets and droplet evaporation, turbulence, breathing and face masks. These
are fascinating and come up in everyday life. And maybe they might come up in
your work if you're an engineer and work about manufacturing physical things.

But typical university physics curriculum is, I guess understandably, focused
on fast-tracking you to the borders of known fundamental physics: quantum
mechanics, particle physics, astrophysics. Whereas the everyday physics builds
on more classical things like thermodynamics, fluid mechanics, heat transfer,
structural mechanics, which are usually covered only quickly, and partially
only in elective courses.

So if you want to learn physics for more practical purposes than understanding
the progress of research in quantum and particle physics, a normal physics
curriculum does not serve you too well. But it still gives you the foundations
to self study these topics.

~~~
jhrmnn
Have a Phd in physics, agree fully. I love talking to people about the physics
and chemistry in every-day life, and you need very little of quantum mechanics
or advanced electromagnetism. Perhaps statistical physics (thermodynamics) is
the single most useful topic.

Also, if you want to understand the science in every-day life, chemistry (or
more broadly materials science) is arguably more relevant than physics per se.

~~~
codesuki
Do you know any books or courses that focus on every day /chemistry? That
would be a nice way to learn.

~~~
cmehdy
I've always thought that one could write a book of recipes that also goes into
the chemistry of things (pressures, heat, types of reactions, acid-base stuff,
etc). Making delicious things while understanding what goes on, which
coincidentally is what sometimes chefs do pretty well when explaining their
recipes (I've discovered Kenji Lopez on HN and he does a bit of that in many
of his videos)

~~~
neutronicus
Also in his cook book, The Food Lab: Better Home Cooking Through Science

------
charleshmartin
Learning physics is not the same as learning to do physics. If you want to
learn how to really do it, you need to work problems.

This means you to learn the techniques, and you need problem books, with
solved examples, that you can work through on your own, or with a small group.
This is absolutely critical. This includes both complex mathematical
calculations as well as back-of-the-envelope calculations.

Moreover, while textbooks are great references, nothing replaces a good video
lecture or presentation, that gets to the heart of the physical concepts
without being overly technical. n And remember that physics is fundamentally
an experimental science. It is not just advanced mathematics. Even if you
yourself are not an experimentalist, you need to understand the basics.

~~~
MengerSponge
I should mention that "good video lectures" are _extremely_ hard to come by.
Experts appreciate a clean narrated delivery, and novices like it too, but
students generally don't learn from a monologue.

You can't just watch videos. You _have_ to work through the problems.

If you have a lot of free time, and you're curious about designing effective
educational multimedia, check out Derek Muller's (of Veritasium fame)
dissertation:
[http://www.physics.usyd.edu.au/super/theses/PhD(Muller).pdf](http://www.physics.usyd.edu.au/super/theses/PhD\(Muller\).pdf)

------
fareesh
My biggest struggles with Physics are psychological.

Because of how the universe works, if you fire a gun and drop a bullet from
the same height they both reach the ground at the same time.

Maybe it's because I have a cartoonish version of physics in my head, my first
instinct is "no that can't be right" and I start from a place of extreme
skepticism that gnaws at me even as I watch myself being proved wrong.

The other common struggle I face is that so much of the physics you learn at a
basic level comes with caveats like "assuming no air resistance" or "in a
vaccuum" or "at sea level" and perfect weights and I end up wondering how
futile all of it seems because in reality I'll never be able to apply this
stuff the way it's being presented. If I have to actually apply it - I'd have
to start thinking all the possible ways in which the system can be affected,
then measure those ways and add them to my calculation.

Then I feel overwhelmed by all the possible things I would need to factor in.
Did I forget friction? Is this surface 100% horizontal? Is it windy right now?
Am I really at sea level? I feel like the street I'm on is 30m higher.

Then I start thinking about the practicality of measuring things. Even if I
eventually learned all of the physics in theory, if I was one of the last 100
people on Earth and the person with the best physics knowledge, could I use it
to build even something as simple as a bridge? How precise would my tools need
to be? Is it ok for my execution to be off by 0.1 degree? Is that too much of
an error? How would I even know?

With programming I feel like there are more opportunities to blackbox things
and focus on building practical solutions, whereas with the material world I
would have to worry about whether I got a faulty batch or whether the
manufacturer was reputable or whether I should have spent more money on a
better manufacturer. By comparison it feels incredibly inaccessible to do
anything tangible with.

~~~
pif
> my first instinct is "no that can't be right"

There's nothing wrong with that. It's also the normal reaction when you are
presented with more advanced concepts, like relativity and quantum mechanics.

It's just a matter of accepting that facts and your instinct can diverge...
and it means that your instinct is wrong!

Which is not to say that you are stupid, no way! On the contrary, it's a sign
that you have embarked on an adventure to discover how the world really works,
which is beyond what evolution may have imprinted in you DNA in order to
survive daily struggles.

> I end up wondering how futile all of it seems because in reality I'll never
> be able to apply this stuff the way it's being presented.

That's a common misconception by non-physicists: that years of advanced
studies can be compared with trivial experience in everyday life, as if the
value of a senior software developer could be judged by how fast he can
install a new version of Visual Studio.

~~~
Rerarom
Funnily, when I was in high-school and made a "trailer" for some programming
lectures I was attending, one of the lines in it I meant to sound "epic" was
"You must use the new version of Visual Studio!"

------
millstone
Susan Fowler is legit terrifyingly brilliant. In only a year and a half she
went from pre-algebra to grad QM while being a writer at NYT. Some people are
just set to a higher gear.

~~~
Retardo_88
"In only a year and a half" \--> How do we know she is not exaggerating?
People have strong incentives to lie about their own accomplishments.

~~~
wrycoder
“Now, she tells her full story for the first time: a story of extraordinary
determination and resilience that reveals what it takes—and what it means—to
be a whistleblower. Long before she arrived at Uber, Fowler's life had been
defined by her refusal to accept her circumstances. She propelled herself from
an impoverished childhood with little formal education to the Ivy League, and
then to a coveted position at one of the most valuable companies in the
history of Silicon Valley. Each time she was mistreated, she fought back or
found a way to reinvent herself; all she wanted was the opportunity to define
her own dreams and work to achieve them. But when she discovered Uber's
pervasive culture of sexism, racism, harassment, and abuse, and that the
company would do nothing about it, she knew she had to speak out--no matter
what it cost her.”

— blurb for her book “Whistleblower”

~~~
Retardo_88
I have no doubt she is smart and resilient. But there is a huge gap between
"smart" and "one-in-a-million genius".

You quoted a marketing blurb. Of course it is supposed to sell the author.

------
kiliantics
Gerard 't Hooft, Nobel laureate in physics has a list of resources to learn
theoretical physics here:

[https://www.goodtheorist.science/](https://www.goodtheorist.science/)

Basically, whenever you become a physicist, especially a Nobel-prize-winning
theorist (this even happened some to me during my non-theoretical PhD), you
get a bunch of emails from cranks that believe they have "figured it out"
without ever having engaged with the centuries of work and results that we are
building on. So he made this reading list that he requires people to be
familiar with before he engages with them. All the information you need is
available and easily accessible and he just curated it into a full course.

------
jeffreyrogers
This is a pretty good list. I used it is a starting point for my own studies.
I just have two comments to make:

1\. It's very likely you do not have good enough math skills to start learning
physics. I have a math minor and CS major, but after being out of school for a
few years I had forgotten a lot of stuff. I needed to spend a week reviewing
algebra and trigonometry and then longer reviewing calculus. This is humbling
but will make your progress a lot easier. If you don't do this there will be
examples you can't follow because you don't know what trick the author is
using to go from one step to another in a solution.

2\. If your mathematical preparation is good you can skip a lot of the
introductory stuff. I.e. just go straight to Taylor's Classical Mechanics, and
Griffith's Introduction to Electrodynamics. You can also learn QM from the
graduate texts. No need to read Griffith's QM book first. I'm working through
Shankar's Principles of Quantum Mechanics and it is definitely doable. He
introduces all the math you need for the rest of the book in the first
chapter, so if you can make it through that (it is mostly linear algebra) you
will be ready for the rest of the book.

~~~
BeetleB
Regarding math, one topic that is often neglected: Asymptotic approximations.
I would often read a grad level textbook, and the author would whip up some
fancy approximation, and it always seemed like brilliant magic. It was
demoralizing: I could never come up with that. Do I not have what it takes to
be a physicist?

Then my math department offered a (rigorous) course on doing asymptotic
approximations. I took it, and it all made sense. There are well known
techniques, and the physics authors were merely using them. Yet it's rarely
taught formally in physics programs. I've occasionally seen it covered as part
of a "Mathematics for physicists" course, but they can cover only so much.

There are books out there on the topic.

------
kuang_eleven
I will second any and all recommendations for reading Griffiths, I have not
met better written textbooks in any field.

~~~
BeetleB
His E&M book is the best, bar none. I know people talk a lot about Jackson,
but a physicist friend gave the best description of Jackson's book: "The best
book to teach me about all kinds of mathematical techniques used in solving
physics problems. My problem solving skills went through the roof because of
Jackson. My understanding of E&M was not at all affected, though."

For E&M intuition, Griffiths is fantastic.

His quantum mechanics book, while decent, is not that great. I don't know if
I've found a single great book on QM.

------
WhiteSage
Beware the first link inside the article redirects you to a phising site
(someone's server got compromised)

------
xchip
The questions is, why do you want to learn physics? And once you answer that
we can give you the contents that will satisfy that "Why", but just giving a
list without any connection with the interests of the reader is useless.

~~~
paulpauper
It is assumed that the reader already has a reason

~~~
xchip
Sure, and depending on it the approach changes

------
daffy
[https://www.bookdepository.com/University-Physics-with-
Moder...](https://www.bookdepository.com/University-Physics-with-Modern-
Physics-SI-Units-Hugh-D-Young/9781292314730)

Is this the full book? I'm confused by some items' being marked as "third
volume".

------
euix
Course of Theoretical Physics by Lev Landau, Evgeny Lifshitz was considered
the gold standard at the graduate level, although not very pedagogical. It's
better to read the particular books after one has already taken a course on
the corresponding subject. Affectionately known as L^2

------
beefield
There was a nice list of good popular physics books in the beginning of the
article. I wonder if anyone has similar lists for other science disciples?

------
mysterypie
You'd like to know more about the author?

[https://www.susanjfowler.com/](https://www.susanjfowler.com/)

------
_hzw
I wish there’s a similar list for modern math.

~~~
Rerarom
[http://math.ucr.edu/home/baez/books.html](http://math.ucr.edu/home/baez/books.html)

There are others, but this one explicitly says

"Math is a much more diverse subject than physics, in a way: there are lots of
branches you can learn without needing to know other branches first... though
you only deeply understand a subject after you see how it relates to all the
others!"

------
supernova87a
"It's a warm summer evening..."

------
Zamicol
The Character of Physical Law by Richard Feynman

was a waste of money and time. It was one of the worse books I've ever read.

~~~
guerrilla
Why?

~~~
Zamicol
It's hard to explain because I found it so unremarkable and banal.

But there was a small part of the book I took particular issue, "Your
expectation on answering the question why goes deep. (No duh!) You might need
to adjust your expectations of understanding to be less rigorous." He says the
same thing in this video:
[https://www.youtube.com/watch?v=36GT2zI8lVA](https://www.youtube.com/watch?v=36GT2zI8lVA)
It's basically his book.

I think not only does this not match my personal experience, experience I've
understood from others at large, but in particular Einstein who had deep
insights because of his depths of understanding "why" in broad categories of
topics. Einstein's brilliance was a synergistic understanding. Better, if we
don't know something, it's best to say, "It's not yet understood" and explain
expected horizons for exploration.

I would compare this attitude to Sabine Hossenfelder who says, "Yes! We can
figure things out including quantum gravity. It's not our 'why's' that are
wrong, but almost certainly our (amazingly crazy) assumptions."

------
pontus
This is a good and accurate list (albeit rather aspirational!) For context, I
did my PhD in physics.

~~~
pontus
Although, referring to Wald as a "high level overview" is not right. In my
mind, Wald is a very abstract and rich book and one that should not be read
until you've mastered GR reasonably well.

------
fizixer
She appears to have taken her "If Susan can..." blog post offline [0]

I do not believe she's coming clean on her learning journey.

[0]
[https://news.ycombinator.com/item?id=24089263](https://news.ycombinator.com/item?id=24089263)

~~~
ridiculous_fish
I think it's just an accidentally fubared link. It's still published:
[https://www.susanjfowler.com/blog/2016/8/26/from-the-
fledgli...](https://www.susanjfowler.com/blog/2016/8/26/from-the-fledgling-
physicist-archives-if-susan-can-learn-physics-so-can-you)

------
paulpauper
The problem with learning physics is there is little to no money involved in
spite of all the work required, unless you plan to teach it or get a job that
requires it. There are plenty of very difficult problems in which finding the
answer can yield an immediate payoff. One such problem is, how do you create
and use cheap google adwords threshold accounts that do not get suspended .
Answering such a question is as intellectually challenging as the hardest of
physics problems but the answer means getting effectively free ads from
google. Same for similar problems in regard to Twitter and Facebook ads.
Fingering out how to evade a social network's spam filter can man a lot of $
if exploited.

