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So You Want to Learn Physics (2016)

susanjfowler.com

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Re: So You Want to Learn Physics (2016)

#101

Post by [deleted] »

naasking wrote: post #95
sleavey wrote: post #4

I went to university intending to study computing science, but switched to physics half way through under the assumption that you could teach yourself computing science more easily than physics. I wouldn't change what I learned for the world, and I'm now in physics academia, but it's funny how my job these days involves using some of the algorithms, mathematics and data structures that I was just about to start learn…

> I think computing science (not just software engineering) is slowly but surely becoming an essential part of many areas of modern physics research. I like to say that physics, mathematics, and computer science are the three pillars of human knowledge. There's some overlap between each pillar, and we don't yet fully understand how each of them fully relate to the others, but each is essential to gathering a full pic…

[deleted]

Re: So You Want to Learn Physics (2016)

#102

Post by Koshkin »

naasking wrote: post #100
Engineering-MD wrote: post #99

Earlier quoted context omitted.

I think there must be more pillars than that. Biology and chemistry while related to physics are distinct (in the same way physics is not maths). More broadly, humanities and the arts are still valid areas of knowledge. Hacker news has a bias towards your three pillars, but I think it is important to acknowledge that human knowledge does go beyond CS, maths and physics.

I disagree re: biology and chemistry. Certainly they are epistemically useful simplifications of the other pillars, but they are not foundational or fundamental . Physics is not math because it's an empirical rather than a priori exploration. We are trying to reproduce the function governing natural laws, where in mathematics we are exploring the properties of functions. Computer science in turn is concerned with the…

> simplifications of the other pillars

This fallacy is called "reductionism."

Re: So You Want to Learn Physics (2016)

#103

Post by Retra »

twtw wrote: post #54
andrepd wrote: post #23

Well I disagree with many of the book choices, but if there's one thing that's absolutely spot-on is this: >One big problem is that a lot of the popular books written about physics (especially those by famous physicists) are incredibly speculative and tend to present an unrealistic view of what the study of physics is all about. When you're learning physics, it's good to avoid these types of speculative books, and st…

> all this crazy complicated and far-fetched ideas, rather than simple and beautiful principles to understand reality Would you mind giving some examples of what kind of "simple and beautiful principles" you have in mind?

Pretty much anything in thermodynamics. Phase changes, energy, entropy, symmetry, action principles, degrees of freedom, fluctuation-dissipation theorem, equipartition theorem, etc..

Re: So You Want to Learn Physics (2016)

#104

Post by Koshkin »

pge wrote: post #36
nyc111 wrote: post #7

Earlier quoted context omitted.

I agree. It seems to me that in those huge physics projects like CERN what most physicists do is programming or data analysis.

This is very true - I was a physics undergrad and learned to code working in a project at cern. While the underlying physics was the foundation of the project, the day to day work was all coding: processing and analyzing the huge amounts of data coming out of the experiment.

> a physics undergrad

Now imagine dozens of people with a PhD in physics doing the same. (Earning a degree in physics is hard.)

Re: So You Want to Learn Physics (2016)

#105

Post by Koshkin »

cyrusmith wrote: post #81

Recommending Griffith to study quantum mechanics is just plain wrong. It's inconsistent, have many gaps in the material. There's a book superior in many regards to Griffith - the "Quantum Mechanics: Concepts and Applications" by Zettili.

There's an astonishingly large number of books on basic QM (only, perhaps, comparable to the number of books about differential forms :). It is probably because each author feels that something is missing or unclear or outdated in all other books. And this is despite the fact that QM in its fundamental shape has been complete since mid-1920s.

Re: So You Want to Learn Physics (2016)

#106

Post by BeetleB »

nyc111 wrote: post #5

> ...the pure joy of understanding the universe around us is one of the most beautiful experiences you can ever have in life. But you do not need to study physics for 25 years in order to understand how the world works. Academic physics that she wants us to learn to undersdand the world is just a new academic subject invented or formalized in the 19. century. Archimedes knew 0 (zero) physics and made huge discoveries…

I think I appreciate the point you are making, but you have gone a little too far in making that point. I've gone through a physics education, and I can attest that one can learn the material, be good at taking exams, and still do a poor job of applying it to the real world.

The other extreme is as problematic, though. Knowing certain formalism in mathematics can really help in expressing a physics principle - and at times it takes a fair amount of seemingly pointless formalism to get to that point.

>Scholastics claim that without spending two years studying calculus you cannot invert a matrix. (Because they make a living teaching you calculus.)

I have no idea where this is coming from. In my education, we were taught matrix inversion a full year before calculus. I've studied matrix inversion multiple times in my academic career, and I don't remember calculus being invoked once.

And to be frank, I'd be extremely wary of anyone claiming strong physics knowledge without learning calculus. Physics gained by leaps and bounds after calculus was introduced. It is the subject one can apply calculus most easily to, and is perhaps the reason we know more physics than any other discipline out there.

Re: So You Want to Learn Physics (2016)

#107

Post by Koshkin »

nyc111 wrote: post #5

> ...the pure joy of understanding the universe around us is one of the most beautiful experiences you can ever have in life. But you do not need to study physics for 25 years in order to understand how the world works. Academic physics that she wants us to learn to undersdand the world is just a new academic subject invented or formalized in the 19. century. Archimedes knew 0 (zero) physics and made huge discoveries…

> But you do not need to study physics for 25 years in order to understand how the world works.

True, that. But to each their own, and so everyone has a different requirement as to the depth of such knowledge to be considered an understanding. A squirrel knows enough about "how the world works" in order to survive - more, perhaps, than we humans do (because we couldn't survive in those conditions). Likewise, a blacksmith may have more firsthand knowledge about the properties of iron and its alloys than a highly-trained theoretical physicist...

Re: So You Want to Learn Physics (2016)

#108

Post by Koshkin »

BeetleB wrote: post #106
nyc111 wrote: post #5

> ...the pure joy of understanding the universe around us is one of the most beautiful experiences you can ever have in life. But you do not need to study physics for 25 years in order to understand how the world works. Academic physics that she wants us to learn to undersdand the world is just a new academic subject invented or formalized in the 19. century. Archimedes knew 0 (zero) physics and made huge discoveries…

I think I appreciate the point you are making, but you have gone a little too far in making that point. I've gone through a physics education, and I can attest that one can learn the material, be good at taking exams, and still do a poor job of applying it to the real world. The other extreme is as problematic, though. Knowing certain formalism in mathematics can really help in expressing a physics principle - and at…

> wary of anyone claiming strong physics knowledge

Well, that depends. Faraday was a great physicist (his claims, whatever they may have been, notwithstanding).

Re: So You Want to Learn Physics (2016)

#109

Post by hintymad »

To put things in perspective, Susan is incredibly talented. She went from barely knowing high school math to enjoying advanced mathematical physics in fewer than three years, which means in this three years, she learned Analysis (not Steward Calculus, but at least Baby Rudin, mind you), Differential Equations, Linear Algebra, Abstract Algebra that covers at least groups, rings, and fields, Functional Analysis, Advanced Probability and Mathematic Statistics, Differential Geometry, to say the least. Besides that, she also needed to learn mechanics, E&M, Quantum Mechanics, and what not. She achieved all these in her part time as she was majored in Psychology. What's even more amazing is that she didn't find her latent talent until she went to college, and she could immediately enjoy Feynman's textbook with almost zero background in Physics!

Bravo! Bravo!

Re: So You Want to Learn Physics (2016)

#110

Post by gotocake »

TangoTrotFox wrote: post #68
andrepd wrote: post #23

Well I disagree with many of the book choices, but if there's one thing that's absolutely spot-on is this: >One big problem is that a lot of the popular books written about physics (especially those by famous physicists) are incredibly speculative and tend to present an unrealistic view of what the study of physics is all about. When you're learning physics, it's good to avoid these types of speculative books, and st…

I'd go the other direction. I think if you taught every single 16 year old a basic class in surface-level understanding of time dilation/length contraction, gravity as a facet of spacetime, the two slit experiment, the twin paradox, relativistic star ships, so forth and so on - you'd see the number of astronomers/physicists skyrocket. They likely would not be able to follow the math and reasons behind, but that's not…

I think you’d find that half or more would be completely unable to grasp the Twin Paradox, or double-slit even in principle, without the math. Probably the number would be closer to three-quarters, or even more if you factor in just how disinterested many would be. I like the idea of a world in which all 16 year olds are both capable of understanding your syllabus, and exposed to it, but I have doubts that we live in that world.

I do think that everyone should have access to such a syllabus though. More realistic if less transformative might be a program of teaching people very basic critical thinking skills. Use advertisements and Instagram posts to analyze deceptive languages and images. Show people that the world they think they live in, that’s projected all of their screens isn’t a very accurate representation of reality. Drive map-territory relations into them via the medium of political, corporate, and interpersonal deception they experience multiple times every day. Maybe half of them would get that, if it was made interesting enough to hold their attention.

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