/r/Physics

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The aim of /r/Physics is to build a subreddit frequented by physicists, scientists, and those with a passion for physics. Papers from physics journals (free or otherwise) are encouraged. Posts should be pertinent, meme-free, and generate a discussion about physics. Please report trolls and incorrect/misleading comments.

The aim of /r/Physics is to build a subreddit frequented by physicists, scientists, and those with a passion for physics. Posts should be pertinent and generate a discussion about physics.


Please choose a user flair using the 'edit' option next to your username above.


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Encouraged submissions

Open-ended discussions
  • Debates and discussions on all topics related to physics are welcome. Please make an effort to engage the community rather than simply state your views and expect others to validate them.

  • Shorter questions which are more straightforward to answer will get a better response in /r/AskPhysics.

Academic publications
  • Links to papers in physics journals (free or otherwise) are welcome. Pre-prints are accepted, but moderators reserve the right to delete any posts that break the rules regarding unscientific content.
Science journalism
  • We invite links to all websites, but article and blog post submissions require proper sourcing from the literature or mainstream scientific journalism. The lack of quality sources is grounds for removal at moderator discretion.

  • If you are posting a link to your own website, please familiarise yourself with the global rules on self-promotion.

Encouraged in weekly threads

Conceptual and closed-ended questions

Careers questions

Education questions

Textbook/resource requests

Discouraged or not allowed

Homework problems

  • Questions that are specific homework problems or calculations should be redirected to /r/AskPhysics or /r/HomeworkHelp. Neither asking nor assisting with homework is allowed here.

  • Alternatively, try Physics Forums instead.

Unscientific content

  • /r/Physics is a place for the discussion of valid and testable science, not pet theories and speculation presented as fact. We aim to be a welcoming place for both academics and the general public, and as such posts with no basis in the current understanding of physics are not allowed as they might serve to misinform.

Sensationalised titles

  • The title of your submission should accurately reflect its contents. If in doubt, use the title of the original research.

Low-effort image/video posts

  • Off-topic images, videos, or otherwise "zero-content" submissions are not allowed. Consider posting to /r/PhysicsJokes, /r/PhysicsGifs, or /r/ScienceImages instead. If you make an image/video post, you should make a comment in the thread describing the relevant physics, linking relevant literature, any computational methods used, etc. This will serve to generate on-topic discussion, and separate your post from low-effort spam. For more information on rules related to these posts, please see this thread here.

Duplicate posts

  • Please make sure that a submission on the same topic has not been posted already.

  • New findings are always reported by multiple publications, and the fact that a specific link has not been submitted does not mean that this topic is not already being discussed on /r/Physics. Feel free to provide links to additional sources in the comment section instead.


Weekly schedule

All threads are posted at 9am EDT (1pm UTC).

Day Post
Mon What are you working on?
Tue Physics Questions
Thu Careers/Education Questions
Fri Resource Recommendations

How to use LaTeX?

First, you will need to install one of the recommended add-ons. To include an equation typeset in LaTeX in your post, put the LaTeX code between [; and ;].

[;i\hbar \frac{\partial}{\partial t} \Psi = \hat H\Psi;]

/r/Physics

2,141,902 Subscribers

1

Guys how is angle theta between B and the vertical is 30 degrees. How did the results add up to this? Is it using the sine rule or something?

0 Comments
2023/02/01
06:25 UTC

2

Are there any conducting supercritical fluids

Supercritical fluids have relatively high density but low viscosity, are there any that are good conductors?

1 Comment
2023/02/01
02:53 UTC

16

Mach2 and Mach8 planes surpass you at the same time, which one do you hear first?

25 Comments
2023/02/01
02:35 UTC

8

Physics Questions - Weekly Discussion Thread - January 31, 2023

This thread is a dedicated thread for you to ask and answer questions about concepts in physics.

Homework problems or specific calculations may be removed by the moderators. We ask that you post these in /r/AskPhysics or /r/HomeworkHelp instead.

If you find your question isn't answered here, or cannot wait for the next thread, please also try /r/AskScience and /r/AskPhysics.

7 Comments
2023/01/31
14:00 UTC

764

Does anyone know how to work neutron scintillators like this?

I have tried putting high voltage on the HV pin of the pmt, but the signal is just noise even though I have an Am-Be neutron source close by. Does any of you have experience with these kinds of detectors?

148 Comments
2023/01/31
12:51 UTC

12

What are you working on? - Weekly Discussion Thread - January 30, 2023

Hello /r/Physics.

It's everyone's favorite day of the week, again. Time to share (or rant about) how your research/work/studying is going and what you're working on this week.

7 Comments
2023/01/30
14:00 UTC

7

Textbooks & Resources - Weekly Discussion Thread - January 27, 2023

This is a thread dedicated to collating and collecting all of the great recommendations for textbooks, online lecture series, documentaries and other resources that are frequently made/requested on /r/Physics.

If you're in need of something to supplement your understanding, please feel welcome to ask in the comments.

Similarly, if you know of some amazing resource you would like to share, you're welcome to post it in the comments.

15 Comments
2023/01/27
14:00 UTC

170

What sparked your interest in Physics?

I really want to hear how everyone got into this subject. :D

203 Comments
2023/01/26
19:15 UTC

14

Careers/Education Questions - Weekly Discussion Thread - January 26, 2023

This is a dedicated thread for you to seek and provide advice concerning education and careers in physics.

If you need to make an important decision regarding your future, or want to know what your options are, please feel welcome to post a comment below.

A few years ago we held a graduate student panel, where many recently accepted grad students answered questions about the application process. That thread is here, and has a lot of great information in it.

Helpful subreddits: /r/PhysicsStudents, /r/GradSchool, /r/AskAcademia, /r/Jobs, /r/CareerGuidance

2 Comments
2023/01/26
14:00 UTC

378

Looking for women to hang in my physics classroom

Last september I started as a high school physics teacher. The classroom I teach in is quite nice and well equipped. At the walls and cabinets there are a lot of posters about famous physicists, made by the previous physics teacher. Think about Newton, Pascal, Joule, Einstein, Coulomb, Rutherford, ... all the famous ones. (Faraday is missing, sadly)

However, there is still room for more, and right now there is not a single poster about a woman. Of course I'm going to give Marie Curie the honour she deserves, but I'm looking for more ideas about who I could hang up on the wall.

The sole criterion is that it has to be about something somewhat tangible for high school students (so no stuff like gluon interactions or christoffel symbols, if you get what I mean)

Thanks for the help and suggestions!

EDIT: Thanks everyone, for all the suggestions and interesting discussions so far. A lot of people pointed out Emmy Noether, and while I agree her discoveries are invaluable for physics, it is a bit too far fetched for high school students and above their level.

Some people pointed out Emilie du Chatelet and I think that is just perfect, as she discovered the relationship between mass, velocity and kinetic energy. Kinetic energy is something very tangible which high school students definitely understand. So when teaching kinetic energy I will be able to refer to her poster.

345 Comments
2023/01/25
13:56 UTC

468

The Anomaly of a Woman in Physics

Recently found an essay ("The Anomaly of a Woman in Physics") by Evelyn Fox Keller on her experience in the Harvard Physics department in the late 1950s. Keller is typically seen as a sociologist or historian of science (she wrote A Feeling for the Organism, a biography on Barbara McClintock the discoverer of transposons), but she had science experiences of her own.

Quote from essay on how foundational questions were undervalued in comparison to more calculation-oriented investigated

I went to graduate school with a vision of theoretical physics as a vehicle for the deepest inquiry into nature—a vision perhaps best personified, in recent times, by Einstein. The use of mathematics to further one’s understanding of the nature of space, time, and matter represented a pinnacle of human endeavor. I went to graduate school to learn about foundations. I was taught, instead, how to do physics. In place of wisdom, I was offered skills. Furthermore, this substitution was made with moralistic fervor. It was wrong, foolhardy, indeed foolish, to squander precious time asking why. Proper humility was to bend to the grindstone and learn techniques. Contemporary physics, under the sway of operationalism, had, it seemed, dispensed with the tradition of Einstein—almost, indeed, with Einstein himself. General relativity, the most intellectually ambitious venture of the century, seemed then (wrongly) a dead subject. Philosophical considerations of any sort in the physical sciences were at an all-time low. Instead, techniques designed to calculate nth-order corrections to a theory grievously flawed at its base were the order of the day.

and on calculation mistakes, deeper questions, and humility

I needed to be humbled. Though I writhed over the banality of the assignments I was given, I did them, acknowledging that I needed in any case to learn the skills. I made frequent arithmetic errors—reflecting a tension that endures within me even today between the expansiveness of conception and the precision of execution, my personal variation perhaps of the more general polar tension in physics as a whole. When my papers were returned with the accuracy of the conception ignored and the arithmetic errors streaked with red—as if with a vengeance—I wondered whether I was studying physics or plumbing. Who has not experienced such a wrenching conflict between idealism and reality? Yet my fellow students seemed oddly untroubled. From the nature of their responses when I tried to press them for deeper understanding of the subject, I thought perhaps I had come from Mars. Why, they wondered, did I want to know? That they were evidently content with the operational success of the formulas mystified me. Even more mystifying was the absence of any appearance of the humility of demeanor that one would expect to accompany the acceptance of more limited goals. I didn’t fully understand then that in addition to the techniques of physics, they were also studying the techniques of arrogance. This peculiar inversion in the meaning of humility was simply part of the process of learning how to be a physicist. It was intrinsic to the professionalization, and what I might even call the masculinization, of an intellectual discipline.

Entire essay is quite interesting and would likely resonate with many who have studied theoretical physics.

137 Comments
2023/01/24
21:04 UTC

5

Physics Questions - Weekly Discussion Thread - January 24, 2023

This thread is a dedicated thread for you to ask and answer questions about concepts in physics.

Homework problems or specific calculations may be removed by the moderators. We ask that you post these in /r/AskPhysics or /r/HomeworkHelp instead.

If you find your question isn't answered here, or cannot wait for the next thread, please also try /r/AskScience and /r/AskPhysics.

19 Comments
2023/01/24
14:00 UTC

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