Are physicists good in EVERY branch of physics?

[yezia]

Hi all,

I've been pondering over this question for a long time. Of course physicists are specialists in a specific branch (even in those branches, sometimes they specialize themselves in an ultra-specific sub-branch) in which they produce research.

I've noticed some professors at my uni (mainly the very old ones), even when teaching only few courses, could talk about really ANYTHING related to physics. I had awesome discussions with theoretical condensed matter physicists about ocean thermodynamics, optics phenomena in the sky, etc.
On a "legendary scale", I can think of Landau and Feynman.

Is this general to anyone who wants to have a career in physics ?
I ask this question because I'm really bad in solid mechanics (rigid bodies) and network analysis lol

 

[Dr Transport]

Its called experience. The older you get, the more you've seen, so the more you are conversant in.

 

[malawi_glenn]

What does "good" mean here? "talking about" is not the same thing as being "good" I think

 

[Vanadium 50]

Its called experience.

As they say, good judgement comes from experience.
And experience cones from bad judgement.

 

[berkeman]

[Mentor Note -- separate discussion about PhD Qualifying Exams has been split off from this thread to here: https://www.physicsforums.com/threads/phd-qualifying-exams-are-they-being-phased-out.1049553/ ]

 

[symbolipoint]

A question is or could be, just how do successful candidates for graduate school maintain all the knowledge and skills they learn so as to pass those qualifyer examinations? Four or five years of study puts them through many important courses, and then the candidate needs to either remember it all or review. So, how? Restudy all that was studied? And then what? Review again, and again?

 

[Dr Transport]

As they say, good judgement comes from experience.
And experience cones from bad judgement.

Take a look at my signature......

 

[andresB]

Define good, and define what you mean by a branch of physics (how specialized are these branches we are talking about?).

 

[yezia]

Sorry everyone, very busy weeks. Thank you all for your answers:
- some of you pointed out how "good" is always relative, for me it's not only have an intuition (not necessarily deep) + being to able to destroy undergrad/grad exercices in anything (a branch here is like Mechanics, Fluids, EM, Optics, GR, QM, Astro, etc.)
- I wasn't aware of the PhD exam, but is it really "general physics"? Like ok you have questions about EM, QM, Optics, for example if you study in condensed matter, but do you have questions about pure mechanics, GR ?
- symbolipoint you made a really great point! For me the "legendary" physicist is so passionate he doesn't need to go back in it since he has intuition about pretty much anything!

 

[MidgetDwarf]

A question is or could be, just how do successful candidates for graduate school maintain all the knowledge and skills they learn so as to pass those qualifyer examinations? Four or five years of study puts them through many important courses, and then the candidate needs to either remember it all or review. So, how? Restudy all that was studied? And then what? Review again, and again?

Restudying becomes faster, if one learned the material "properly" the first time. Moreover, upon doing more "advanced" courses, one has gained practice doing math/physics what Evers. Which helps build insight, greater intuition,... ( In theory)

 

[ohwilleke]

Hi all,

I've been pondering over this question for a long time. Of course physicists are specialists in a specific branch (even in those branches, sometimes they specialize themselves in an ultra-specific sub-branch) in which they produce research.

I've noticed some professors at my uni (mainly the very old ones), even when teaching only few courses, could talk about really ANYTHING related to physics. I had awesome discussions with theoretical condensed matter physicists about ocean thermodynamics, optics phenomena in the sky, etc.
On a "legendary scale", I can think of Landau and Feynman.

Is this general to anyone who wants to have a career in physics ?
I ask this question because I'm really bad in solid mechanics (rigid bodies) and network analysis lol

Compared to whom?

Physics are generally better than biologists, organic chemists, and english professors at almost all aspects of physics. Occasionally, an inorganic physical chemist will be a bit sharper than some non-specialist physicists when it comes to condensed matter physics or thermodynamics, both of which heavily overlap, and sometimes engineers can be neck and neck with physicists on applied physics problems.

Physicists are more knowledgable about their specialty than about areas outside their specialization. But the foundational physics courses, advanced mathematics, and the worldview that physics promotes, insures that pretty much everyone who can legitimately call themselves a physicist is more knowledgable about physics than 99%+ of people who do not call themselves physicists.

Trouble with solid mechanics is a bit surprising, as that is ordinarily considered an "easier" part of classical physics (although civil and structural engineers would beg to differ). Network analysis, by which I assume you mean analyzing electrical circuits, is likewise bread and butter stuff.

Before you abandon the career, however, it sounds to me like what you really need is tutoring and a good study group. If you have even pre-calculus down solid, these are surmountable barriers that can be easily bridged with guidance and addition studying.

If the problem, however, is that the math is overwhelming, you may be headed down the wrong path as mathematically, neither of these parts of intro physics are particularly challenging compared to intermediate and advanced level physics courses. If that is the problem, you might consider a scientific discipline that is a bit less mathematically intensive like geology or biology.

 

[symbolipoint]

.....

If the problem, however, is that the math is overwhelming, you may be headed down the wrong path as mathematically, neither of these parts of intro physics are particularly challenging compared to intermediate and advanced level physics courses. If that is the problem, you might consider a scientific discipline that is a bit less mathematically intensive like geology or biology.

Be very careful about that advice. Mathematical skills and knowledge in ANY natural or physical science must never be discounted; and must never be thought to be as if granted. One may find in some situation of one of those "less mathematically intensive" sciences that some particular mathematics could save you and others much confusion and to bring some predictable order to a problem you may be attending.

 

[hutchphd]

A question is or could be, just how do successful candidates for graduate school maintain all the knowledge and skills they learn so as to pass those qualifyer examinations? Four or five years of study puts them through many important courses, and then the candidate needs to either remember it all or review. So, how? Restudy all that was studied? And then what? Review again, and again?

Teach the full curriculum at least once. Worked pretty well for me IMHO. (I still can't do thermodynamics)

 

[ohwilleke]

Be very careful about that advice. Mathematical skills and knowledge in ANY natural or physical science must never be discounted; and must never be thought to be as if granted. One may find in some situation of one of those "less mathematically intensive" sciences that some particular mathematics could save you and others much confusion and to bring some predictable order to a problem you may be attending.

Perhaps. But, physics requires fluency with three semesters of vector calculus, linear algebra, differential equations, complex analysis, and applied analysis, on top of calculus based probability and statistics at a minimum. Some of these classes (together with organic chemistry) have the highest flunk out rates in the entire undergraduate curriculum. Getting there over the course of two or three years from being weak at precalculus is an almost insurmountable task.

In contrast, getting to a place, say, in genetics, where you are doing D-statistics and f3 and f4 statistics and principle component analysis, while challenging, is a place you can get to from being weak at precalculus in two or three years if you have grit and buckle down. Maybe you need three or four semesters of college level math to do it. This isn't math for people who don't like math. But physics and many kinds of engineering are absolute the very most math intensive curricula you can have short of being an outright math major. In an undergraduate physics or math major:

SAT-M 600 seems to be the lowest score at which even a very motivated student has a chance for mastery [defined at 3.5 GPA or better in your major]. From the data one might guess that only for SAT-M well above 700 do students have more than a 50 percent chance of obtaining GPA > 3.5. That is, a student with average motivation or conscientiousness probably needs SAT-M well above 700 to have a high probability of obtaining mastery.

Put another way: "kids in the top 1% of math ability (say, SAT-M > 750) had only a 50% chance of graduating in the physics major with more A's than B's -- i.e., in-major GPA > 3.5."

This extreme threshold effect isn't present in many other STEM disciplines (except engineering and perhaps chemistry). In other STEM disciplines, if you work hard you can overcome being weak in math as of the end of your high school years when you take the SATs or ACTs. But, you can't do that in math or physics.

Also, while there is a place for the mathematically savvy to make a huge contribution in almost any STEM field (and a lot of non-STEM fields), not everyone in a field needs to make those contributions, and if you are looking for a STEM niche that matches your strengths and weaknesses you can find it. There is no shame in pursuing a STEM major that doesn't require you to take eight semesters of intense, difficult for lots people judged by the percentage of people who fail them, math courses in addition to the actual science classes in your major over the course of an undergraduate degree.

But there really is no place in physics anywhere for someone who isn't chomping at the bit to take calculus by storm freshman year and most of your peers will have at least a semester or two of it under their belt in high school already.

 

[symbolipoint]

@ohwilleke
About my "Be careful about that advice,..." commentary, I had been one of those mathematically lesser people who often restudied some of the more "basic" stuff, and then found the reconditioning to be a great benefit when employed in industry. You would be amazed how some people will say, "I had to study so much algebra and calculus but I never used any of it". How things would go that way for them, hard to understand. But I FOUND basic math/arithmetic and often very simple basic algebra to be extremely helpful.

 

[vela]

Physicists just pretend to know everything.

 

[yezia]

Compared to whom?

Physics are generally better than biologists, organic chemists, and english professors at almost all aspects of physics. Occasionally, an inorganic physical chemist will be a bit sharper than some non-specialist physicists when it comes to condensed matter physics or thermodynamics, both of which heavily overlap, and sometimes engineers can be neck and neck with physicists on applied physics problems.

Physicists are more knowledgable about their specialty than about areas outside their specialization. But the foundational physics courses, advanced mathematics, and the worldview that physics promotes, insures that pretty much everyone who can legitimately call themselves a physicist is more knowledgable about physics than 99%+ of people who do not call themselves physicists.

Trouble with solid mechanics is a bit surprising, as that is ordinarily considered an "easier" part of classical physics (although civil and structural engineers would beg to differ). Network analysis, by which I assume you mean analyzing electrical circuits, is likewise bread and butter stuff.

Before you abandon the career, however, it sounds to me like what you really need is tutoring and a good study group. If you have even pre-calculus down solid, these are surmountable barriers that can be easily bridged with guidance and addition studying.

If the problem, however, is that the math is overwhelming, you may be headed down the wrong path as mathematically, neither of these parts of intro physics are particularly challenging compared to intermediate and advanced level physics courses. If that is the problem, you might consider a scientific discipline that is a bit less mathematically intensive like geology or biology.

I've explained in the thread what I mean by "being good" in a branch of physics. There is no comparison with "non-physicists" here.

No need to be condescending regarding the Solids/Circuits/Maths part, don't worry I'm doing quite good in my degree.

Physicists just pretend to know everything.

View attachment 321878

Ahah I love this. Do you know the author ? I would love to see some more of his comics !

 

[Swamp Thing]

Ahah I love this. Do you know the author ? I would love to see some more of his comics !

https://xkcd.com/

 

[DrJohn]

When I started lecturing in chemistry, I was given several topics to teach that I wasn't particularly good at as a student, so had to read up on each one to refresh enough to do the basics. Over time the repitition of these courses meant that I could recall the content of them relatively easily. So to my students I seemed good. As long as I knew more than them, I always had no problem with things I taught regularly, and with the several topics I had done badly at as a student. But I was not good at the ones I never had to teach and had struggled a bit with when younger. But I was usually better than the the students. And that's what counts.

I always wondered as a student myself why the lecturers seemed to have such a wide ranging knowledge of things outside their specialism. It's repitition making you familiar with it and easier to find the solution - more tracks and memories in your mind leading to an answer. Enabling you to comment of things outside your specialist subject.

I went to a conference which was totally about my specialisation, and one Ph.D student gave his present, sounding very nervous. I could barely follow his talk, and thought I must have forgotten a lot of things, it seemed beyond my knowledge. At the any questions stage, someone stood up, and suggested one part was wrong, with an alternative explanation, which seemed convincing - lots of people nodding, as he said what would have happened if the student speaker had been right. Then instantly a second person stood up and said the first critic was right about the error, but his explanation was wrong, and explained why it was wrong and gave a second alternative explaination. Wow, criticising an explanation and alternative explanation on a complex subject he had just heard 10 seconds ago. Lots of people nodding and ooing oh yes.

Then a third person stood up, gave his name and was immediately recognised as a nobel prize winner, (who just happened to be in town visiting an friend) but not a specialist in the topics of the conference. He told the original presenter what their error was, then told the first critic what was really wrong with his alternative explanation, told the second critic that he was wrong in each alternative he had offered (including his wrong explanation of what was wrong) and then explained what was really really going on.

Silence. Every one sat going through what this not a specialist had said about everything, and slowly we all started nodding in agreement. We were all wiped out by how he could correct things outside of his own specialism and also how we all took so long to work out he was right. Genius is truely impressive when it swings into action.

 

[yezia]

When I started lecturing in chemistry, I was given several topics to teach that I wasn't particularly good at as a student, so had to read up on each one to refresh enough to do the basics. Over time the repitition of these courses meant that I could recall the content of them relatively easily. So to my students I seemed good. As long as I knew more than them, I always had no problem with things I taught regularly, and with the several topics I had done badly at as a student. But I was not good at the ones I never had to teach and had struggled a bit with when younger. But I was usually better than the the students. And that's what counts.

I always wondered as a student myself why the lecturers seemed to have such a wide ranging knowledge of things outside their specialism. It's repitition making you familiar with it and easier to find the solution - more tracks and memories in your mind leading to an answer. Enabling you to comment of things outside your specialist subject.

I went to a conference which was totally about my specialisation, and one Ph.D student gave his present, sounding very nervous. I could barely follow his talk, and thought I must have forgotten a lot of things, it seemed beyond my knowledge. At the any questions stage, someone stood up, and suggested one part was wrong, with an alternative explanation, which seemed convincing - lots of people nodding, as he said what would have happened if the student speaker had been right. Then instantly a second person stood up and said the first critic was right about the error, but his explanation was wrong, and explained why it was wrong and gave a second alternative explaination. Wow, criticising an explanation and alternative explanation on a complex subject he had just heard 10 seconds ago. Lots of people nodding and ooing oh yes.

Then a third person stood up, gave his name and was immediately recognised as a nobel prize winner, (who just happened to be in town visiting an friend) but not a specialist in the topics of the conference. He told the original presenter what their error was, then told the first critic what was really wrong with his alternative explanation, told the second critic that he was wrong in each alternative he had offered (including his wrong explanation of what was wrong) and then explained what was really really going on.

Silence. Every one sat going through what this not a specialist had said about everything, and slowly we all started nodding in agreement. We were all wiped out by how he could correct things outside of his own specialism and also how we all took so long to work out he was right. Genius is truely impressive when it swings into action.

Wow that's an incredible little story you had there! You made some great points about this "teacher has more knowledge than students because of repetition".

And yeah genius is something outstanding to encounter; I would have loved to meet people as Landau or Feynman, I had 2 professors whom I may call "scientific geniuses" (1 of them led France's graduate team to great rankings in the International Physics Tournament, and the other, I believe, read every books ever written about ALL physics subjects because of a deep love for the field).

My highschool philosophy teacher used to tell us how lucky we were to have all those books written by some of the greatests of all time. Every night they were sleeping next to us, ready to wake up at any time, and ready to let us seat inside their complex mind. And not only this, but they lend us a cup of coffee, ready to debate with us despite being dead sometimes hundreds of years ago.

 

[symbolipoint]

Wow that's an incredible little story you had there! You made some great points about this "teacher has more knowledge than students because of repetition".

Not enough attention is given often enough to that.

 

[vanhees71]

Teach the full curriculum at least once. Worked pretty well for me IMHO. (I still can't do thermodynamics)

At this stage of education, you can skip phenomenlogical thermodynamics and learn it as ans application of statistical physics. In statistical physics (again at your level of education) it's easier to start with the quantum version and get the classical version by making the according approximations ;-).