The following outline is provided as an overview of and topical guide to physics:

Physicsnatural science that involves the study of matter[1] and its motion through spacetime, along with related concepts such as energy and force.[2] More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.[3][4][5]

What type of subject is physics?

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Physics can be described as all of the following:

  • An academic discipline – one with academic departments, curricula and degrees; national and international societies; and specialized journals.
  • A scientific field (a branch of science) – widely recognized category of specialized expertise within science, and typically embodies its own terminology and nomenclature. Such a field will usually be represented by one or more scientific journals, where peer-reviewed research is published.

Branches

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  • Astronomy – studies the universe beyond Earth, including its formation and development, and the evolution, physics, chemistry, meteorology, and motion of celestial objects (such as galaxies, planets, etc.) and phenomena that originate outside the atmosphere of Earth (such as the cosmic background radiation).
    • Astrodynamics – application of ballistics and celestial mechanics to the practical problems concerning the motion of rockets and other spacecraft.
    • Astrometry – the branch of astronomy that involves precise measurements of the positions and movements of stars and other celestial bodies.
    • Astrophysics – the study of the physical aspects of celestial objects
    • Celestial mechanics – the branch of theoretical astronomy that deals with the calculation of the motions of celestial objects such as planets.
    • Extragalactic astronomy – the branch of astronomy concerned with objects outside our own Milky Way Galaxy
    • Galactic astronomy – the study of our own Milky Way galaxy and all its contents.
    • Physical cosmology – the study of the largest-scale structures and dynamics of the universe and is concerned with fundamental questions about its formation and evolution.
    • Planetary science – the scientific study of planets (including Earth), moons, and planetary systems, in particular those of the Solar System and the processes that form them.
    • Stellar astronomy – natural science that deals with the study of celestial objects (such as stars, planets, comets, nebulae, star clusters, and galaxies) and phenomena that originate outside the atmosphere of Earth (such as cosmic background radiation)
  • Atmospheric physics – the study of the application of physics to the atmosphere
  • Atomic, molecular, and optical physics – the study of how matter and light interact
    • Optics – the branch of physics which involves the behavior and properties of light, including its interactions with matter and the construction of instruments that use or detect it.
  • Biophysics – interdisciplinary science that uses the methods of physics to study biological systems
    • Neurophysics – branch of biophysics dealing with the nervous system.
    • Polymer physics – field of physics that studies polymers, their fluctuations, mechanical properties, as well as the kinetics of reactions involving degradation and polymerization of polymers and monomers respectively.
    • Quantum biology – application of quantum mechanics to biological phenomenon.
  • Chemical physics – the branch of physics that studies chemical processes from physics.
  • Computational physics – study and implementation of numerical algorithms to solve problems in physics for which a quantitative theory already exists.
  • Condensed matter physics – the study of the physical properties of condensed phases of matter.
  • Electricity – the study of electrical phenomena.
  • Electromagnetism – branch of science concerned with the forces that occur between electrically charged particles.
  • Geophysics – the physics of the Earth and its environment in space; also the study of the Earth using quantitative physical methods
  • Magnetism – the study of physical phenomena that are mediated by magnetic field.
  • Mathematical physics – application of mathematics to problems in physics and the development of mathematical methods for such applications and the formulation of physical theories.
  • Mechanics – the branch of physics concerned with the behavior of physical bodies when subjected to forces or displacements, and the subsequent effects of the bodies on their environment.
    • Aerodynamics – study of the motion of air.
    • Biomechanics – the study of the structure and function of biological systems such as humans, animals, plants, organs, and cells using the methods of mechanics.
    • Classical mechanics – one of the two major sub-fields of mechanics, which is concerned with the set of physical laws describing the motion of bodies under the action of a system of forces.
    • Continuum mechanics – the branch of mechanics that deals with the analysis of the kinematics and the mechanical behavior of materials modeled as a continuous mass rather than as discrete particles.
    • Dynamics – the study of the causes of motion and changes in motion
    • Fluid mechanics – the study of fluids and the forces on them.
    • Statics – the branch of mechanics concerned with the analysis of loads (force, torque/moment) on physical systems in static equilibrium, that is, in a state where the relative positions of subsystems do not vary over time, or where components and structures are at a constant velocity.
  • Medical Physics – the branch of physics that deals with the application of physics in medicine – such as imaging exams (NMR, PET scans, and so on), radiotherapy and nuclear medicine.
  • Statistical mechanics – the branch of physics which studies any physical system that has a large number of degrees of freedom.
  • Thermodynamics – the branch of physical science concerned with heat and its relation to other forms of energy and work.
  • Nuclear physics – field of physics that studies the building blocks and interactions of atomic nuclei.
  • Particle physics – the branch of physics that studies the properties and interactions of the fundamental constituents of matter and energy.
  • Psychophysics – quantitatively investigates the relationship between physical stimuli and the sensations and perceptions they affect.
  • Plasma physics – the study of plasma, a state of matter similar to gas in which a certain portion of the particles are ionized.
  • Quantum physics – branch of physics dealing with physical phenomena where the action is on the order of the Planck constant.
    • Quantum field theory – the application of quantum theory to the study of fields (systems with infinite degrees of freedom).
    • Quantum information theory – the study of the information-processing capabilities afforded by quantum mechanics.
    • Quantum foundations – the discipline focussing in understanding the counterintuitive aspects of the theory, including trying to find physical principles underlying them, and proposing generalisations of quantum theory.
  • Quantum gravity – the search for an account of gravitation fully compatible with quantum theory.
  • Relativity – theory of physics which describes the relationship between space and time.
  • Other
    • Agrophysics – the study of physics applied to agroecosystems
      • Soil physics – the study of soil physical properties and processes.
    • Cryogenics – cryogenics is the study of the production of very low temperature (below −150 °C, −238 °F or 123 K) and the behavior of materials at those temperatures.
    • Econophysics – interdisciplinary research field, applying theories and methods originally developed by physicists to solve problems in economics
    • Materials physics – use of physics to describe materials in many different ways such as force, heat, light, and mechanics.
    • Vehicle dynamics – dynamics of vehicles, here assumed to be ground vehicles.
  • Philosophy of physics – deals with conceptual and interpretational issues in modern physics, many of which overlap with research done by certain kinds of theoretical physicists.

History

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History of physics – history of the physical science that studies matter and its motion through space-time, and related concepts such as energy and force

General concepts

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Basic principles

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Physics – branch of science that studies matter[9] and its motion through space and time, along with related concepts such as energy and force.[10] Physics is one of the "fundamental sciences" because the other natural sciences (like biology, geology etc.) deal with systems that seem to obey the laws of physics. According to physics, the physical laws of matter, energy and the fundamental forces of nature govern the interactions between particles and physical entities (such as planets, molecules, atoms or the subatomic particles). Some of the basic pursuits of physics, which include some of the most prominent developments in modern science in the last millennium, include:

Gravity, light, physical system, physical observation, physical quantity, physical state, physical unit, physical theory, physical experiment

Theoretical concepts: mass–energy equivalence, elementary particle, physical law, fundamental force, physical constant

Fundamental concepts

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Measurement

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Motion

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Overview

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This is a list of the primary theories in physics, major subtopics, and concepts.

Note: the Theory column below contains links to articles with infoboxes at the top of their respective pages which list the major concepts.
Theory Major subtopics Concepts
Classical mechanics Newton's laws of motion, Lagrangian mechanics, Hamiltonian mechanics, kinematics, statics, dynamics, chaos theory, acoustics, fluid dynamics, continuum mechanics Density, dimension, gravity, space, time, motion, length, position, velocity, acceleration, mass, momentum, force, energy, angular momentum, torque, conservation law, harmonic oscillator, wave, work, power
Electromagnetism Electrostatics, electrodynamics, electricity, magnetism, Maxwell's equations, optics Capacitance, electric charge, electric current, electrical conductivity, electric field, electric permittivity, electrical resistance, electromagnetic field, electromagnetic induction, electromagnetic radiation, Gaussian surface, magnetic field, magnetic flux, magnetic monopole, magnetic permeability
Theory of relativity Special relativity, general relativity, Einstein field equations Covariance, Einstein manifold, equivalence principle, four-momentum, four-vector, general principle of relativity, geodesic motion, gravity, gravitoelectromagnetism, inertial frame of reference, invariance, length contraction, Lorentzian manifold, Lorentz transformation, metric, Minkowski diagram, Minkowski space, principle of relativity, proper length, proper time, reference frame, rest energy, rest mass, relativity of simultaneity, spacetime, special principle of relativity, speed of light, stress–energy tensor, time dilation, twin paradox, world line
Thermodynamics and statistical mechanics Heat engine, kinetic theory Boltzmann constant, conjugate variables, enthalpy, entropy, equation of state, equipartition theorem, first law of thermodynamics, free energy, heat, ideal gas law, internal energy, irreversible process, partition function, pressure, reversible process, second law of thermodynamics, spontaneous process, state function, statistical ensemble, temperature, thermodynamic equilibrium, thermodynamic potential, thermodynamic processes, thermodynamic state, thermodynamic system, third law of thermodynamics, viscosity, zeroth law of thermodynamics
Quantum mechanics Path integral formulation, scattering theory, Schrödinger equation, quantum field theory, quantum statistical mechanics Adiabatic approximation, correspondence principle, free particle, Hamiltonian, Hilbert space, identical particles, matrix mechanics, Planck constant, operators, quanta, quantization, quantum entanglement, quantum harmonic oscillator, quantum number, quantum tunneling, Schrödinger's cat, Dirac equation, spin, wavefunction, wave mechanics, wave–particle duality, zero-point energy, Pauli exclusion principle, Heisenberg uncertainty principle

Concepts by field

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Field Subfields Major theories Concepts
Particle physics Accelerator physics, nuclear physics, nuclear astrophysics, particle astrophysics, particle physics phenomenology Standard Model, quantum field theory, quantum chromodynamics, electroweak theory, effective field theory, lattice field theory, lattice gauge theory, gauge theory, supersymmetry, Grand Unified Theory, superstring theory, M-theory Fundamental force (gravitational, electromagnetic, weak, strong), elementary particle, spin, antimatter, spontaneous symmetry breaking, brane, string, quantum gravity, theory of everything, vacuum energy
Atomic, molecular, and optical physics Atomic physics, molecular physics, atomic and molecular astrophysics, chemical physics, optics, photonics Quantum optics, quantum chemistry, quantum information science Atom, molecule, diffraction, electromagnetic radiation, laser, polarization, spectral line, Casimir effect
Condensed matter physics Solid state physics, high pressure physics, low-temperature physics, nanoscale and mesoscopic physics, polymer physics BCS theory, Bloch's theorem, Fermi gas, Fermi liquid, many-body theory Phases (gas, liquid, solid, Bose–Einstein condensate, superconductor, superfluid), electrical conduction, magnetism, self-organization, spin, spontaneous symmetry breaking
Astrophysics Cosmology, gravitation physics, high-energy astrophysics, planetary astrophysics, plasma physics, space physics, stellar astrophysics Big Bang, Lambda-CDM model, cosmic inflation, general relativity, law of universal gravitation Black hole, cosmic background radiation, cosmic string, cosmos, dark energy, dark matter, galaxy, gravity, gravitational radiation, gravitational singularity, planet, Solar System, star, supernova, universe, nova

Lists

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Index of physics articles

See also

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Notes

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  1. ^ Richard Feynman begins his Lectures with the atomic hypothesis, as his most compact statement of all scientific knowledge: "If, in some cataclysm, all of scientific knowledge were to be destroyed, and only one sentence passed on to the next generations ..., what statement would contain the most information in the fewest words? I believe it is ... that all things are made up of atoms – little particles that move around in perpetual motion, attracting each other when they are a little distance apart, but repelling upon being squeezed into one another. ..." R. P. Feynman; R. B. Leighton; M. Sands (1963). The Feynman Lectures on Physics. Vol. 1. p. I-2. ISBN 978-0-201-02116-5.
  2. ^ J. C. Maxwell (1878). Matter and Motion. D. Van Nostrand. p. 9. ISBN 978-0-486-66895-6. Physical science is that department of knowledge which relates to the order of nature, or, in other words, to the regular succession of events.
  3. ^ H.D. Young; R.A. Freedman (2004). University Physics with Modern Physics (11th ed.). Addison Wesley. p. 2. Physics is an experimental science. Physicists observe the phenomena of nature and try to find patterns and principles that relate these phenomena. These patterns are called physical theories or, when they are very well established and of broad use, physical laws or principles.
  4. ^ S. Holzner (2006). Physics for Dummies. Wiley. p. 7. Bibcode:2005pfd..book.....H. ISBN 978-0-470-61841-7. Physics is the study of your world and the world and universe around you.
  5. ^ Note: The term 'universe' is defined as everything that physically exists: the entirety of space and time, all forms of matter, energy and momentum, and the physical laws and constants that govern them. However, the term 'universe' may also be used in slightly different contextual senses, denoting concepts such as the cosmos or the philosophical world.
  6. ^ Edmund Taylor Whittaker (1904). A Treatise on the Analytical Dynamics of Particles and Rigid Bodies. Cambridge University Press. ISBN 978-0-521-35883-5.
  7. ^ Joseph Stiles Beggs (1983). Kinematics. Taylor & Francis. p. 1. ISBN 978-0-89116-355-8.
  8. ^ Thomas Wallace Wright (1896). Elements of Mechanics Including Kinematics, Kinetics and Statics. E and FN Spon. Chapter 1.
  9. ^ At the start of The Feynman Lectures on Physics, Richard Feynman offers the atomic hypothesis as the single most prolific scientific concept: "If, in some cataclysm, all [] scientific knowledge were to be destroyed [save] one sentence [...] what statement would contain the most information in the fewest words? I believe it is [...] that all things are made up of atoms – little particles that move around in perpetual motion, attracting each other when they are a little distance apart, but repelling upon being squeezed into one another ..." (Feynman, Leighton & Sands 1963, p. I-2)
  10. ^ "Physical science is that department of knowledge which relates to the order of nature, or, in other words, to the regular succession of events." (Maxwell 1878, p. 9)

Works cited

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