What is Physics: Definition and 990 Discussions

Physics (from Ancient Greek: φυσική (ἐπιστήμη), romanized: physikḗ (epistḗmē), lit. 'knowledge of nature', from φύσις phýsis 'nature') is the natural science that studies matter, its motion and behavior through space and time, and the related entities of energy and force. Physics is one of the most fundamental scientific disciplines, and its main goal is to understand how the universe behaves.Physics is one of the oldest academic disciplines and, through its inclusion of astronomy, perhaps the oldest. Over much of the past two millennia, physics, chemistry, biology, and certain branches of mathematics were a part of natural philosophy, but during the Scientific Revolution in the 17th century these natural sciences emerged as unique research endeavors in their own right. Physics intersects with many interdisciplinary areas of research, such as biophysics and quantum chemistry, and the boundaries of physics are not rigidly defined. New ideas in physics often explain the fundamental mechanisms studied by other sciences and suggest new avenues of research in academic disciplines such as mathematics and philosophy.
Advances in physics often enable advances in new technologies. For example, advances in the understanding of electromagnetism, solid-state physics, and nuclear physics led directly to the development of new products that have dramatically transformed modern-day society, such as television, computers, domestic appliances, and nuclear weapons; advances in thermodynamics led to the development of industrialization; and advances in mechanics inspired the development of calculus.

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  1. ateixeira

    Is Returning to Physics After Years in Finance a Good Idea?

    Hello everybody! I signed up to this blog a long time ago but I don't think I ever made a post in here before. I finished my degree in Physics more than 5 years ago, started my PhD but never finished it. After that I moved back to Angola and followed a careers in consulting and on the financial...
  2. A

    Constrained motion of a ring along a horizontal rod

    The correct answer is u=vcos\theta. I have understood so far to be able to conclude that \text{displacement of string} = PA - PC \approx AB Also, \overline{AB}=\overline{AC}cos\theta or, more generally, \vec{S}_{along\ the\ string}=(\vec{S}_{along\ the\ horizontal})cos\theta Now, I had hoped...
  3. K

    Does the Gender Ratio on PF Reflect the Wider Physics Community?

    Just out of curiosity, has anyone tried to find out whether the male/female/other ratio here is similar to that in the general physics community? It seems to me that everyone I've engaged with on PF is male! Food for thought?
  4. P

    History Interesting anecdotes in the history of physics?

    Let us try to promote some physics history in this sub. What are some anecdotes in the history of physics that you want to share? Be it a true story or a popular myth. I'll start: I recently tried to check if the story of Schrödinger's equation was true: Schrödinger going out for the...
  5. walkeraj

    Just a middle-aged amateur person into physics

    Degree in chemistry and at one point was a physics and mathematics double major, but life intervened. Never got to finish but still read and work on novel amateur theory. At least, what I would call novel and amateur. My focus is on putting together theory on space-time and quantum field...
  6. Ronald_James

    Admissions Seeking Feedback on my Physics Personal Statement for Uni Application

    Hello everyone, I am a mature student applying to an undergraduate course with a foundation year, and as I finalize my university application, I'm seeking valuable feedback on the content and structure of my personal statement. I would greatly appreciate any insights and perspectives you may...
  7. S

    Tension Question with One Mass and Two Pulleys

    My question is how come the tension in pulley 2 is pointing downwards. I was under the impression that tension always points away from the mass.
  8. sbrothy

    Is N. David Mermin's Autobiography Relevant for Today's STEM Scholars?

    [rant clipped] I digress, meander even...I found this: Autobiographical Notes of a Physicist under physics.hist.ph. A place I suspect not many of you look regularly ;) Which sounds pretty prejudiced I'm aware. :) ) This guy's experiences may well be out of date for the need of todays STEM...
  9. H

    Applying for a PhD in Physics after a Master's degree

    Hi, I have a few questions about the timeline of pursuing a PhD after a master's degree. Applying for PhDs seems quite a hassle as of now because each university has their own set of application procedures, academic requirements and deadlines. I am currently in the process of navigating where...
  10. thematrix1101

    Admissions Comments on my physics PhD applicant profile

    Hello! As I nervously wait to hear back from my physics PhD applications, I thought it would be helpful to see what you guys think of my profile and the schools I applied to. Note: I am a senior undergrad and will be graduating this upcoming summer. Domestic applicant. Research Field: Quantum...
  11. Ken_S

    What Drives the Quest to Uncover the Origins of Mass, Energy, Time, and Charge?

    Studying physics and related topics for 3 decades. Working on a project to better understand the origin of mass, energy, time and charge.
  12. C

    I Understanding Ultrasound Attenuation and Reflection in Aluminum Sheets

    Hello. I write this in regards to enquiring whether you can address various questions I have in relation to acoustics and the physics of sound. In particular, I am interested in ultrasound. I have various questions in relation to it. In particular, I am interested in understanding the nature...
  13. J

    The destructive force of a 1,000kg boulder hurled by a catapult

    Homework Statement: Could be silly to some, but I am writing a short story and hope someone can help. Relevant Equations: I am clueless, forgive me. Hello all! I tried asking Bing/CoPilot, Google, and visited some medieval war machine forums, but could not find something that could help me...
  14. K

    What Factors Cause a Water Container to Tip Over When Accelerated?

    Not clear how to proceed. Does the cylindrical surface of the ungula need to be considered?
  15. torquefan

    Can a Passion for Torque Propel a Career in Physics?

    Hi, I'm Torque fan. A fan of torque or a fan that generates torque whichever you feel like. I'm a physics enthusiast and I want to further my knowledge on the subject and pursue it as a career if fate has it for me! I also want to contribute to the forum in helping people wherever I can and...
  16. P

    A Correspondence between areal radius differences and proper distances

    Other ways of wording this finding about the extended SC (Schwarzschild) spacetime: - in the local frame of a free faller, radial distance is given r coordinate difference - in either Fermi-normal coordinates, or Riemann-Normal coordinates built from a free faller at an event, coordinate...
  17. phi_skr

    What are the latest developments in nanotech device experiments?

    Hi, I am a physics graduate student focusing on experiment related to nanotech devices.
  18. garra

    Studying Can I be a good theorist without a degree in math?

    I wondered this when i saw that Robert Penrose its a physicist and a mathematician. If i dont do a math physics degree I wont be effective?
  19. jbrandew

    I Reason for Opposite Signs for Terms in Faraday's Law and Ampere's Law

    Hello, im a bit confused about the right term in Faradays Law vs the right most term in Amperes Law. They both seem like terms corresponding to a resistance to change, similar to inertia. As in, the induced electric field from a changing magnetic field has an opposite direction compared to the...
  20. F

    I Variation of the lightning train thought experiment

    Hi all, I've been going over some special relativity as it's a topic I never really studied during my younger years and wanted to get to grips with it, especially since it's such a fundamental part of our understanding of the cosmos. I was reading about Einsteins train lightning thought...
  21. robotkid786

    What are the basics of atomic science and cosmology?

    New to the forum, hoping to study as much physics as I can understand. Atomic science interests me, and so does cosmology - but i'm still so new that I don't know enough maths for the latter, and havent got much knowledge on the former aside from gcse chemistry which was over 10 years ago
  22. M

    Does the Universe have a finite number of fundamentals to uncover?

    Fire, Gravity, Electromagnetism, Atoms, DNA, Steam power, Nuclear, Quarks. All of these things have one thing in common. They are fundamental aspects of the universe that humans have uncovered and given names. However, all of these great discoveries occured quite some time ago and as a science...
  23. tomj

    Can Information be Defined in Physics? Exploring Attempts and Controversies

    Just looking around for now, but would love to see links to attempts to define information in physics
  24. Lao Tzu

    Questing for the unification of mathematics and my intuition

    Howdy from West Virginia!! If you would have told me 30 years ago that I'd be researching physics and math for fun, I would have said, "Are you high.... and by the way, what is physics?!?" I'm obsessed with all things science, and tickled by all things quantum. I became interested in science and...
  25. robotkid786

    Physics How important is python for theoretical physics?

    Hey guys, I'm a first year student studying theoretical physics in England. My physics modules include a fair bit of python programming and I want to apply to ICGs cosmology PhD in England. Can I escape learning python by choosing maths modules?
  26. srnixo

    Understanding Time Measurement in Physics: Uncertainty and Calculations

    So as you can see in the image, I have noted the time in the [time column (s) ] on the table after conducting the experiment at home using the application phyphox. And now, I have some questions to fill in the remaining gaps: The first question: about ΔH (m) : Should I set it equal to zero...
  27. Marco211298

    What is the Role of Physics in Mechanical Engineering?

    Hi everyone, i’m Marco and i am here to learn about physics! I am a mechanical technician from Italy.
  28. J

    Find out kinetic Energy using Rutherford Formula

    Hello everyone, I am working on this problem and I think I almost solved it, but then I noticed, that I do not know what values I have for dn, n and dθ. Can anyone help me with this?
  29. abrogard

    Forces Required For Steeling A Blade?

    A question, this. Something I would like to know. Practical physics I think. 'Applied physics' I believe. I wondered at the purpose and efficacy of 'steeling' knives and learned that the process is intended to repair damage to an edge rather than 'sharpen' in the sense of 'create a sharp...
  30. VeryNice

    Physics Extended Essay about Gauss' law and/or Lorentz force

    Hi. This is not exactly a homework problem, but I'm posting to ask for help for my extended essay. I am doing the IB (international baccalaureate) program and we are required to write a 4000 words extended essay on any subject. I decided to do mine on physics (through process of elimination...
  31. Overdose_

    Finding the focal length of a converging lens with VERY limited info

    This is the solution but I do not understand??? How could they just assume the object distance equals 2f? No magnification is given here. We know the candle produces a real image and the distance is limited, so that means it must be somewhere between the principal focus, the center of curvature...
  32. Skoceko

    What are the latest developments in discrete Quantum Field Theories?

    I have been interested in physics for a very long time. Initially in high school celestial mechanics and soon afterwards quantum mechanics. During my chemistry studies I specialized in quantum chemistry at the end of my bachelor and continued to do a Bachelor and Master in pure Mathematics, with...
  33. M

    Why kinetic energy of system of particles is not equal to p^2/2m

    It is good for the people who wants to know physics and it's beauty
  34. CallMeDirac

    How great is the overlap of Philosophy and Physics?

    For much of physics, its language is fundamentally math, but to a certain point, does philosophical thinking ever play an important part in creating or exploring physics? It would seem, at least to me, that there is some significant overlap, given that much of understanding physics can't quite...
  35. BugKingpin

    Exploring the Physics of Gene Expression: A Math/Physics Major's Perspective

    Hello everyone, I am interested in researching the underlying physics of gene expression. I'm a junior in a math/physics double bachelors program.
  36. K

    I Jonathan Oppenheim, "A postquantum theory of classical gravity?"

    in the news String Theory gets Competition: A New Attempt to Solve Physics' Biggest Mystery Sabine Hossenfelder based on Jonathan Oppenheim, "A postquantum theory of classical gravity?", Jonathan Oppenheim et al, "Gravitationally induced decoherence vs space-time diffusion: testing the...
  37. M

    Free Researcher as physics engineer

    I am a physic Engineer, researcher and I do search on nuclear and paticle physic. I need some basic reaearch on physic at the last years and I belive that you can answer my questions. If not enough these inform me , please inform me which information need you to me. Thank you. Best regards...
  38. Greg Bernhardt

    Physics Award

    Please select up to 3 members who were most impactful in the Physics forums in 2023. This is a popular vote. Polls were created by weighing activity and measure of helpfulness. Everyone nominated should feel honored. Many more could be added to this poll, we can never realistically add everyone...
  39. T

    Admissions How Can I Overcome Limited Research Experience for Grad School in Physics?

    Alright so here's the deal: I graduated recently (spring '23) from Ohio State University with a BS in physics. I graduated with honors and magna cum laude (3.8 ish gpa). I took the general GRE and got 162 verbal, 165 quant, and 4.5 writing. I spent some time in a master program to pursue...
  40. T

    I Understanding Ground State Degeneracy in the Transverse Ising Model

    Hi all, I was wondering if there was a reference/textbook where the degenerate perturbation calculation for the Transverse Ising model was treated fully. I want to better understand how in the weak magnetic field limit, the ground state degeneracy only lifts at N'th order in perturbation theory...
  41. Ben Messer

    Is Sabine Hossenfelder the Key to Unlocking New Theories in Physics?

    Neil deGrasse Tyson has been a great "goto" and respected physicist for me to follow online. I've read Einstein's biography and have been fascinated with the world as theorized by some of the greatest minds and proofs. Recently, I've come across a name I've never known. Admittedly, this is a...
  42. L

    Two point masses, where is the force zero?

    Hi, I had no problems calculating parts a and b, but I am having problems with task c For ##F## I got the following, with ##\vec{r}= \left(\begin{array}{c} x \\\ y \\\ 0 \end{array}\right)## , ##\vec{r}_1= \left(\begin{array}{c} -a \\\ 0 \\\ 0 \end{array}\right)## and ##\vec{r}_2=...
  43. P

    Fortran Errors in Fortran code for solving Laplace's equation in 3D

    hey everyone. I wrote a code in Fortran to calculate potential values or solve the Laplace equation inside a cube according to the boundary conditions mentioned in the code. this is my code: program laplace_cubic implicit none REAL*8 :: LX, LY, LZ, DELTA, MAX_ERR, ERR INTEGER :: NX, NY...
  44. Leticia

    Hello! I'm an undergrad student looking to discuss physics

    Hello! I'm in sixth semester of Physics undergrad, I'm looking for a place to talk to other physics students and discuss interesting problems and questions. I'm happy to meet you!
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