Our website is made possible by displaying online advertisements to our visitors.
Please consider supporting us by disabling your ad blocker.
Portal:Physics
The Physics Portal
Physics is the scientific study of matter, its fundamental constituents, 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. A scientist who specializes in the field of physics is called a physicist.
Physics is one of the oldest academic disciplines. 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 branched into separate research endeavors. 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 these and other academic disciplines such as mathematics and philosophy.
Advances in physics often enable new technologies. For example, advances in the understanding of electromagnetism, solid-state physics, and nuclear physics led directly to the development of technologies that have transformed modern 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. (Full article...)
Featured article -
This is a Featured article, which represents some of the best content on English Wikipedia.
The eye is a region of mostly calm weather at the center of a tropical cyclone. The eye of a storm is a roughly circular area, typically 30–65 kilometers (19–40 miles; 16–35 nautical miles) in diameter. It is surrounded by the eyewall, a ring of towering thunderstorms where the most severe weather and highest winds of the cyclone occur. The cyclone's lowest barometric pressure occurs in the eye and can be as much as 15 percent lower than the pressure outside the storm.
In strong tropical cyclones, the eye is characterized by light winds and clear skies, surrounded on all sides by a towering, symmetric eyewall. In weaker tropical cyclones, the eye is less well defined and can be covered by the central dense overcast, an area of high, thick clouds that show up brightly on satellite imagery. Weaker or disorganized storms may also feature an eyewall that does not completely encircle the eye or have an eye that features heavy rain. In all storms, however, the eye is where the barometer reading is lowest. (Full article...)
Did you know -
.jpg)
- ... that Femto satellites are the smallest types of satellites, and the Kalam SAT is one of the smallest Femto satellite ever made?
Selected image -
An arc lamp or arc light is a lamp that produces light by an electric arc (also called a voltaic arc). The carbon arc light, which consists of an arc between carbon electrodes in air, invented by Humphry Davy in the early 1800s, was the first practical electric light. It was widely used starting in the 1870s for street and large building lighting until it was superseded by the incandescent light in the early 20th century. It continued in use in more specialized applications where a high intensity point light source was needed, such as searchlights and movie projectors until after World War II.
-
The 15 kW xenon short-arc lamp used in the IMAX projection system -
A mercury arc lamp from a fluorescence microscope -
A krypton long arc lamp (top) is shown above a xenon flashtube. The two lamps, used for laser pumping, are very different in the shape of the electrodes, in particular, the cathode, (on the left). -
A krypton arc lamp during operation. -
An electric arc, demonstrating the “arch” effect
Related portals
Good articles -
These are Good articles, which meet a core set of high editorial standards.
-
The radioactive beta decay is due to the weak interaction, which transforms a neutron into a proton, an electron, and an electron antineutrino.
In nuclear physics and particle physics, the weak interaction, also called the weak force, is one of the four known fundamental interactions, with the others being electromagnetism, the strong interaction, and gravitation. It is the mechanism of interaction between subatomic particles that is responsible for the radioactive decay of atoms: The weak interaction participates in nuclear fission and nuclear fusion. The theory describing its behaviour and effects is sometimes called quantum flavordynamics (QFD); however, the term QFD is rarely used, because the weak force is better understood by electroweak theory (EWT).
The effective range of the weak force is limited to subatomic distances and is less than the diameter of a proton. (Full article...) -
Sir Rudolf Ernst Peierls, CBE FRS (/ˈpaɪ.ərlz/; German: [ˈpaɪɐls]; 5 June 1907 – 19 September 1995) was a German-born British physicist who played a major role in Tube Alloys, Britain's nuclear weapon programme, as well as the subsequent Manhattan Project, the combined Allied nuclear bomb programme. His 1996 obituary in Physics Today described him as "a major player in the drama of the eruption of nuclear physics into world affairs".
Peierls studied physics at the University of Berlin, at the University of Munich under Arnold Sommerfeld, the University of Leipzig under Werner Heisenberg, and ETH Zurich under Wolfgang Pauli. After receiving his DPhil from Leipzig in 1929, he became an assistant to Pauli in Zurich. In 1932, he was awarded a Rockefeller Fellowship, which he used to study in Rome under Enrico Fermi, and then at the Cavendish Laboratory at the University of Cambridge under Ralph H. Fowler. Because of his Jewish background, he elected to not return home after Adolf Hitler's rise to power in 1933, but to remain in Britain, where he worked with Hans Bethe at the Victoria University of Manchester, then at the Mond Laboratory at Cambridge. In 1937, Mark Oliphant, the newly appointed Australian professor of physics at the University of Birmingham recruited him for a new chair there in applied mathematics. (Full article...) -
James Franck (German pronunciation: [ˈdʒɛɪ̯ms ˈfʁaŋk] ⓘ; 26 August 1882 – 21 May 1964) was a German physicist who won the 1925 Nobel Prize in Physics with Gustav Hertz "for their discovery of the laws governing the impact of an electron upon an atom". He completed his doctorate in 1906 and his habilitation in 1911 at the Frederick William University in Berlin, where he lectured and taught until 1918, having reached the position of professor extraordinarius. He served as a volunteer in the German Army during World War I. He was seriously injured in 1917 in a gas attack and was awarded the Iron Cross 1st Class.
Franck became the Head of the Physics Division of the Kaiser Wilhelm Gesellschaft for Physical Chemistry. In 1920, Franck became professor ordinarius of experimental physics and Director of the Second Institute for Experimental Physics at the University of Göttingen. While there he worked on quantum physics with Max Born, who was Director of the Institute of Theoretical Physics. His work included the Franck–Hertz experiment, an important confirmation of the Bohr model of the atom. He promoted the careers of women in physics, notably Lise Meitner, Hertha Sponer and Hilde Levi. (Full article...) -
Wu Zhonghua (Chinese: 吴仲华; 27 July 1917 – 19 September 1992), also known as Chung-Hua Wu, was a Chinese physicist. He was a National Advisory Committee for Aeronautics (NACA) researcher, Tsinghua University professor, and Founding Director of the Institute of Engineering Thermophysics of the Chinese Academy of Sciences (CAS). He pioneered the general theory of three-dimensional flow for turbomachinery, which has been widely used in aircraft engine designs. Wu and his wife Li Minhua were both academicians of the CAS.
Born in Shanghai, Wu's college education at Tsinghua University was interrupted by the Second Sino-Japanese War. He graduated from the temporary National Southwestern Associated University and was awarded a Boxer Indemnity Scholarship to study at the Massachusetts Institute of Technology in the United States. After earning his Ph.D., he joined the NACA, the predecessor of NASA, where he developed the theory of three-dimensional flow. (Full article...) -
Hendrik Antoon Lorentz (right) after whom the Lorentz group is named and Albert Einstein whose special theory of relativity is the main source of application. Photo taken by Paul Ehrenfest 1921.
The Lorentz group is a Lie group of symmetries of the spacetime of special relativity. This group can be realized as a collection of matrices, linear transformations, or unitary operators on some Hilbert space; it has a variety of representations. This group is significant because special relativity together with quantum mechanics are the two physical theories that are most thoroughly established, and the conjunction of these two theories is the study of the infinite-dimensional unitary representations of the Lorentz group. These have both historical importance in mainstream physics, as well as connections to more speculative present-day theories. (Full article...) -
Maria Goeppert Mayer (German: [maˈʁiːa ˈɡœpɐt ˈmaɪɐ] ⓘ; née Göppert; June 28, 1906 – February 20, 1972) was a German-American theoretical physicist and Nobel laureate in Physics for proposing the nuclear shell model of the atomic nucleus. She was the second woman to win a Nobel Prize in Physics, the first being Marie Curie. In 1986, the Maria Goeppert-Mayer Award for early-career women physicists was established in her honor.
A graduate of the University of Göttingen, Goeppert Mayer wrote her doctoral thesis on the theory of possible two-photon absorption by atoms. At the time, the chances of experimentally verifying her thesis seemed remote, but the development of the laser in the 1960s later permitted this. Today, the unit for the two-photon absorption cross section is named the Goeppert Mayer (GM) unit. (Full article...) -
John Tucker "Chick" Hayward (15 November 1908 – 23 May 1999) was an American naval aviator during World War II. He helped develop one of the two atomic bombs that was dropped on Japan in the closing days of the war. Later, he was a pioneer in the development of nuclear propulsion, nuclear weapons, guidance systems for ground- and air-launched rockets, and underwater anti-submarine weapons. A former batboy for the New York Yankees, Hayward dropped out of high school and lied about his age to enlist in the United States Navy at age 16. He was subsequently admitted to the United States Naval Academy at Annapolis, from which he graduated 51st in his class of 1930. He volunteered for naval aviation.
During World War II, he served at the Naval Aircraft Factory in Philadelphia, where he was involved in an effort to improve aircraft instrumentation, notably the compass and altimeter. He attended the University of Pennsylvania's Moore School of Electrical Engineering, and studied nuclear physics. In June 1942, he assumed command of a new patrol bomber squadron, VB-106, equipped with PB4Y-1 Liberators, which he led in a daring raid on Wake Island, in the Solomon Islands campaign, and in the Southwest Pacific Area. Returning to the United States in 1944, he was posted to the Naval Ordnance Test Station at Inyokern, California, where he joined the Manhattan Project, participating in Project Camel, the development of the non-nuclear components of the Fat Man bomb, and in its drop testing. (Full article...) -
Sir Joseph Rotblat KCMG CBE FRS (4 November 1908 – 31 August 2005) was a Polish and British physicist. During World War II he worked on Tube Alloys and the Manhattan Project, but left the Los Alamos Laboratory on grounds of conscience after it became clear to him in 1944 that Germany had ceased development of an atomic bomb.
His work on nuclear fallout was a major contribution toward the ratification of the 1963 Partial Nuclear Test Ban Treaty. A signatory of the 1955 Russell–Einstein Manifesto, he was secretary-general of the Pugwash Conferences on Science and World Affairs from their founding until 1973 and shared, with the Pugwash Conferences, the 1995 Nobel Peace Prize "for efforts to diminish the part played by nuclear arms in international affairs and, in the longer run, to eliminate such arms." (Full article...) -
Maria Salomea Skłodowska-Curie (Polish: [ˈmarja salɔˈmɛa skwɔˈdɔfska kʲiˈri] ⓘ; née Skłodowska; 7 November 1867 – 4 July 1934), known simply as Marie Curie (/ˈkjʊəri/ KURE-ee; French: [maʁi kyʁi]), was a Polish and naturalised-French physicist and chemist who conducted pioneering research on radioactivity. She was the first woman to win a Nobel Prize, the first person to win a Nobel Prize twice, and the only person to win a Nobel Prize in two scientific fields. Her husband, Pierre Curie, was a co-winner of her first Nobel Prize, making them the first married couple to win the Nobel Prize and launching the Curie family legacy of five Nobel Prizes. She was, in 1906, the first woman to become a professor at the University of Paris.
She was born in Warsaw, in what was then the Kingdom of Poland, part of the Russian Empire. She studied at Warsaw's clandestine Flying University and began her practical scientific training in Warsaw. In 1891, aged 24, she followed her elder sister Bronisława to study in Paris, where she earned her higher degrees and conducted her subsequent scientific work. In 1895, she married the French physicist Pierre Curie, and she shared the 1903 Nobel Prize in Physics with him and with the physicist Henri Becquerel for their pioneering work developing the theory of "radioactivity"—a term she coined. In 1906, Pierre Curie died in a Paris street accident. Marie won the 1911 Nobel Prize in Chemistry for her discovery of the elements polonium and radium, using techniques she invented for isolating radioactive isotopes. Under her direction, the world's first studies were conducted into the treatment of neoplasms by the use of radioactive isotopes. She founded the Curie Institute in Paris in 1920, and the Curie Institute in Warsaw in 1932; both remain major medical research centres. During World War I, she developed mobile radiography units to provide X-ray services to field hospitals. (Full article...) -
A force is an influence that can cause an object to change its velocity unless counterbalanced by other forces. The concept of force makes the everyday notion of pushing or pulling mathematically precise. Because the magnitude and direction of a force are both important, force is a vector quantity. The SI unit of force is the newton (N), and force is often represented by the symbol F.
Force plays an important role in classical mechanics. The concept of force is central to all three of Newton's laws of motion. Types of forces often encountered in classical mechanics include elastic, frictional, contact or "normal" forces, and gravitational. The rotational version of force is torque, which produces changes in the rotational speed of an object. In an extended body, each part often applies forces on the adjacent parts; the distribution of such forces through the body is the internal mechanical stress. In equilibrium, these stresses cause no acceleration of the body as the forces balance one another. If these are not in equilibrium, they can cause deformation of solid materials or flow in fluids. (Full article...) -
Blue plaque to physicists Frisch and Peierls on the wall of the Poynting Physics Building, University of Birmingham
The Frisch–Peierls memorandum was the first technical exposition of a practical nuclear weapon. It was written by expatriate German-Jewish physicists Otto Frisch and Rudolf Peierls in March 1940 while they were both working for Mark Oliphant at the University of Birmingham in Britain during World War II.
The memorandum contained the first calculations about the size of the critical mass of fissile material needed for an atomic bomb. It revealed that the amount required might be small enough to incorporate into a bomb that could be delivered by air. It also anticipated the strategic and moral implications of nuclear weapons. (Full article...) -
Sir John Douglas Cockcroft (27 May 1897 – 18 September 1967) was an English nuclear physicist who shared the 1951 Nobel Prize in Physics with Ernest Walton for splitting the atomic nucleus, which was instrumental in the development of nuclear power.
After service on the Western Front with the Royal Field Artillery during the Great War, Cockcroft studied electrical engineering at Manchester Municipal College of Technology whilst he was an apprentice at Metropolitan Vickers Trafford Park and was also a member of their research staff. He then won a scholarship to St. John's College, Cambridge, where he sat the tripos exam in June 1924, becoming a wrangler. Ernest Rutherford accepted Cockcroft as a research student at the Cavendish Laboratory, and Cockcroft completed his doctorate under Rutherford's supervision in 1928. With Walton and Mark Oliphant, he built what became known as a Cockcroft–Walton generator. Cockcroft and Walton used this to perform the first artificial disintegration of an atomic nucleus, a feat popularly known as splitting the atom. (Full article...) -
Aage Niels Bohr (Danish: [ˈɔːwə ˈne̝ls ˈpoɐ̯ˀ] ⓘ; 19 June 1922 – 8 September 2009) was a Danish nuclear physicist who shared the Nobel Prize in Physics in 1975 with Ben Roy Mottelson and James Rainwater "for the discovery of the connection between collective motion and particle motion in atomic nuclei and the development of the theory of the structure of the atomic nucleus based on this connection". His father was Niels Bohr.
Starting from Rainwater's concept of an irregular-shaped liquid drop model of the nucleus, Bohr and Mottelson developed a detailed theory that was in close agreement with experiments. (Full article...) -
Norman Foster Ramsey Jr. (August 27, 1915 – November 4, 2011) was an American physicist who was awarded the 1989 Nobel Prize in Physics for the invention of the separated oscillatory field method (see Ramsey interferometry), which had important applications in the construction of atomic clocks. A physics professor at Harvard University for most of his career, Ramsey also held several posts with such government and international agencies as NATO and the United States Atomic Energy Commission. Among his other accomplishments are helping to found the United States Department of Energy's Brookhaven National Laboratory and Fermilab. (Full article...) -
Calutron Girls photographed by Ed Westcott at their calutron control panels at Y-12
The Calutron Girls were a group of young women—mostly high school graduates—who had joined the Manhattan Project at the Y-12 National Security Complex located at Oak Ridge, Tennessee, from 1943 to 1945. Although they were not allowed to know at the time, they were monitoring dials and watching meters for calutrons, mass spectrometers adapted for separation of uranium isotopes for the development of nuclear weapons for use during World War II. The enriched uranium was used to make the "Little Boy" atomic bomb for the Hiroshima nuclear bombing on August 6, 1945. (Full article...)
_crop.jpg)
February anniversaries
- 15 February 1564 – Galileo Galilei's birthday
- 18 February 1745 – Alessandro Volta's birthday
- 15 February 1786 – Cat's Eye Nebula discovered
- 18 February 1838 – Ernst Mach's birthday
- 11 February 1847 – Thomas Edison's birthday
- 23 February 1855 – Carl Friedrich Gauss's death
- 22 February 1875 – Heinrich Hertz's birthday
- 28 February 1901 – Linus Pauling's birthday
- 18 February 1967 – J. Robert Oppenheimer's death
- 13 February 1910 – William Shockley's birthday
- 15 February 1988 – Richard Feynman died
- 28 February 2020 – Freeman Dyson's death
General images
The following are images from various physics-related articles on Wikipedia.
-
A Feynman diagram representing (left to right) the production of a photon (blue sine wave) from the annihilation of an electron and its complementary antiparticle, the positron. The photon becomes a quark–antiquark pair and a gluon (green spiral) is released. (from History of physics) -
Image of X-ray diffraction pattern from a protein crystal (from Condensed matter physics) -
The ancient Greek mathematician Archimedes, developer of ideas regarding fluid mechanics and buoyancy. (from History of physics) -
Galileo Galilei, early proponent of the modern scientific worldview and method (1564–1642) (from History of physics) -
Max Planck (1858–1947) (from History of physics) -
A magnet levitating above a high-temperature superconductor. Today some physicists are working to understand high-temperature superconductivity using the AdS/CFT correspondence. (from Condensed matter physics) -
Classical physics (Rayleigh–Jeans law, black line) failed to explain black-body radiation – the so-called ultraviolet catastrophe. The quantum description (Planck's law, colored lines) is said to be modern physics. (from Modern physics) -
The quantum Hall effect: Components of the Hall resistivity as a function of the external magnetic field (from Condensed matter physics) -
-
The Polish astronomer Nicolaus Copernicus (1473–1543) is remembered for his development of a heliocentric model of the Solar System. (from History of physics) -
Richard Feynman's Los Alamos ID badge (from History of physics) -
The Standard Model (from History of physics) -
Gottfried Leibniz (1646–1716) (from History of physics) -
Michael Faraday (1791–1867) (from History of physics) -
The first Bose–Einstein condensate observed in a gas of ultracold rubidium atoms. The blue and white areas represent higher density. (from Condensed matter physics) -
Marie Skłodowska-Curie
(1867–1934) was awarded two Nobel prizes, Physics (1903) and Chemistry (1911) (from History of physics) -
One possible signature of a Higgs boson from a simulated proton–proton collision. It decays almost immediately into two jets of hadrons and two electrons, visible as lines. (from History of physics) -
Ludwig Boltzmann (1844–1906) (from History of physics) -
-
Alessandro Volta (1745–1827) (from History of physics) -
Albert Einstein (1879–1955), photographed here in around 1905 (from History of physics) -
-
Heike Kamerlingh Onnes and Johannes van der Waals with the helium liquefactor at Leiden in 1908 (from Condensed matter physics) -
-
A composite montage comparing Jupiter (lefthand side) and its four Galilean moons (top to bottom: Io, Europa, Ganymede, Callisto) (from History of physics) -
Christiaan Huygens (1629–1695) (from History of physics) -
Rudolf Clausius (1822–1888) (from History of physics) -
Werner Heisenberg (1901–1976) (from History of physics) -
James Clerk Maxwell (1831–1879) (from History of physics) -
Einstein proposed that gravitation is a result of masses (or their equivalent energies) curving ("bending") the spacetime in which they exist, altering the paths they follow within it. (from History of physics) -
The Hindu-Arabic numeral system. The inscriptions on the edicts of Ashoka (3rd century BCE) display this number system being used by the Imperial Mauryas. (from History of physics) -
Sir Isaac Newton (1642–1727) (from History of physics) -
Computer simulation of nanogears made of fullerene molecules. It is hoped that advances in nanoscience will lead to machines working on the molecular scale. (from Condensed matter physics) -
Daniel Bernoulli (1700–1782) (from History of physics) -
William Thomson (Lord Kelvin)
(1824–1907) (from History of physics) -
-
Star maps by the 11th century Chinese polymath Su Song are the oldest known woodblock-printed star maps to have survived to the present day. This example, dated 1092, employs the cylindricalequirectangular projection. (from History of physics) -
An artist's rendition of Kepler-62f, a potentially habitable exoplanet discovered using data transmitted by the Kepler space telescope, named after Kepler. (from History of physics) -
J. J. Thomson (1856–1940) discovered the electron and isotopy and also invented the mass spectrometer. He was awarded the Nobel Prize in Physics in 1906. (from History of physics) -
Johannes Kepler.(1571–1630) (from History of physics) -
Classical physics is usually concerned with everyday conditions: speeds are much lower than the speed of light, sizes are much greater than that of atoms, yet very small in astronomical terms. Modern physics, however, is concerned with high velocities, small distances, and very large energies. (from Modern physics) -
René Descartes (1596–1650) (from History of physics) -
Chien-Shiung Wu worked on parity violation in 1956 and announced her results in January 1957. (from History of physics)
-Portrait-Portr_10971.tif_(cropped).jpg)
_in_1958.jpg)
Categories
Fundamentals: Concepts in physics | Constants | Physical quantities | Units of measure | Mass | Length | Time | Space | Energy | Matter | Force | Gravity | Electricity | Magnetism | Waves
Basic physics: Mechanics | Electromagnetism | Statistical mechanics | Thermodynamics | Quantum mechanics | Theory of relativity | Optics | Acoustics
Specific fields: Acoustics | Astrophysics | Atomic physics | Molecular physics | Optical physics | Computational physics | Condensed matter physics | Nuclear physics | Particle physics | Plasma physics
Tools: Detectors | Interferometry | Measurement | Radiometry | Spectroscopy | Transducers
Background: Physicists | History of physics | Philosophy of physics | Physics education | Physics journals | Physics organizations
Other: Physics in fiction | Physics lists | Physics software | Physics stubs
Physics topics
Classical physics traditionally includes the fields of mechanics, optics, electricity, magnetism, acoustics and thermodynamics. The term Modern physics is normally used for fields which rely heavily on quantum theory, including quantum mechanics, atomic physics, nuclear physics, particle physics and condensed matter physics. General and special relativity are usually considered to be part of modern physics as well.
More recognized content
Associated Wikimedia
The following Wikimedia Foundation sister projects provide more on this subject:
-
Commons
Free media repository -
Wikibooks
Free textbooks and manuals -
Wikidata
Free knowledge base -
Wikinews
Free-content news -
Wikiquote
Collection of quotations -
Wikisource
Free-content library -
Wikiversity
Free learning tools -
Wikivoyage
Free travel guide -
Wiktionary
Dictionary and thesaurus
Sources
Portals on Wikipedia
Previous Page Next Page
