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. It 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 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...)

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The Manhattan Project was a research and development program undertaken during World War II to produce the first nuclear weapons. It was led by the United States in collaboration with the United Kingdom and Canada. The Manhattan Project employed nearly 130,000 people at its peak and cost nearly US$2 billion (equivalent to about $28 billion in 2024).

From 1942 to 1946, the project was directed by Major General Leslie Groves of the U.S. Army Corps of Engineers. Nuclear physicist J. Robert Oppenheimer was the director of the Los Alamos Laboratory that designed the bombs. The Army program was designated the Manhattan District, as its first headquarters were in Manhattan; the name superseded the initial codename, Development of Substitute Materials, for the entire project. The project absorbed its earlier British counterpart, Tube Alloys. (Full article...)

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...that while Albert Einstein is most famous for his Theory of Relativity, he was awarded the Nobel Prize for his explanation of the photoelectric effect?

...that gravitational tidal accelerations are the result of the curvature of spacetime?

...that the blue glow of the Cherenkov effect is due to electrons moving faster than the speed of light in water?

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Archimedes' screw, also called the Archimedean screw or screwpump, is a machine historically used for transferring water from a low-lying body of water into irrigation ditches. The screw pump is commonly attributed to Archimedes on the occasion of his visit to Egypt, but this tradition may reflect only that the apparatus was unknown to the Greeks before Hellenistic times and introduced in his lifetime by unknown Greek engineers. Some writers have suggested that the device may have been in use in Assyria some 350 years earlier.

Archimedes' screw was operated by hand and could raise water efficiently
An Archimedes' screw in Huseby south of Växjö Sweden
Archimedes' screw]
Roman screw used to dewater mines in Spain
Modern Archimedes' screws which have replaced some of the windmills used to drain the polders at Kinderdijk in the Netherlands
Archimedes' screw as a form of art by Tony Cragg at 's-Hertogenbosch in the Netherlands

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These are Good articles, which meet a core set of high editorial standards.

Image 1

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...)
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Henry DeWolf "Harry" Smyth (/ˈhɛnri dəˈwʊlf ˈsmaɪθ/; May 1, 1898 – September 11, 1986) was an American physicist, diplomat, and bureaucrat. He played a number of key roles in the early development of nuclear energy, as a participant in the Manhattan Project, a member of the U.S. Atomic Energy Commission (AEC), and U.S. ambassador to the International Atomic Energy Agency (IAEA).

Educated at Princeton University and the University of Cambridge, he was a faculty member in Princeton's Department of Physics from 1924 to 1966. He chaired the department from 1935 to 1949. His early research was on the ionization of gases, but his interests shifted toward nuclear physics beginning in the mid-1930s. (Full article...)
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Hartford City Glass Company was among the top three window glass manufacturers in the United States between 1890 and 1899, and continued to be one of the nation's largest after its acquisition. It was also the country's largest manufacturer of chipped glass, with capacity double that of its nearest competitor. The company's works was the first of eight glass plants that existed in Hartford City, Indiana during the Indiana Gas Boom. It became the city's largest manufacturer and employer, peaking with 600 employees.

Many of the skilled workers employed at the Hartford City Glass Company were from Belgium, at the time the world's leading manufacturer of window glass. The Belgian workers and their families accounted for over one-third of Hartford City's population during the 1890s, and lived on the city's south side. Because of the importance of the French-speaking Belgians, one of the local newspapers featured articles in French. (Full article...)
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Fourteenth-century drawing of angels turning the celestial spheres

Ancient, medieval and Renaissance astronomers and philosophers developed many different theories about the dynamics of the celestial spheres. They explained the motions of the various nested spheres in terms of the materials of which they were made, external movers such as celestial intelligences, and internal movers such as motive souls or impressed forces. Most of these models were qualitative, although a few of them incorporated quantitative analyses that related speed, motive force and resistance. (Full article...)
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The Nobel Prize in Physics is an annual award given by the Royal Swedish Academy of Sciences for those who have made the most outstanding contributions to mankind in the field of physics. It is one of the five Nobel Prizes established by the will of Alfred Nobel in 1895 and awarded since 1901, the others being the Nobel Prize in Chemistry, Nobel Prize in Literature, Nobel Peace Prize, and Nobel Prize in Physiology or Medicine.

The prize consists of a medal along with a diploma and a certificate for the monetary award. The front side of the medal displays the same profile of Alfred Nobel depicted on the medals for Physics, Chemistry, and Literature. (Full article...)
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"Thin Man" plutonium gun test casings

"Thin Man" was the code name for a proposed plutonium-fueled gun-type nuclear bomb that the United States partially developed during the Manhattan Project. Its development was abandoned in 1944 after it was discovered that the spontaneous fission rate of nuclear reactor-bred plutonium was too high for use in a gun-type design due to the high concentration of the isotope plutonium-240. (Full article...)
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The Type Ib supernova SN 2008D in galaxy NGC 2770, shown in X-ray (left) and visible light (right), at the corresponding positions of the images. (NASA image.)

Type Ib and Type Ic supernovae are categories of supernovae that are caused by the stellar core collapse of massive stars. These stars have shed or been stripped of their outer envelope of hydrogen, and, when compared to the spectrum of Type Ia supernovae, they lack the absorption line of silicon. Compared to Type Ib, Type Ic supernovae are hypothesized to have lost more of their initial envelope, including most of their helium. (Full article...)
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Electricity is invisible, but it can yield visually observable phenomena, shown here with the flash of lightning and various forms of electric light in the buildings.

Electricity is the set of physical phenomena associated with the presence and motion of matter possessing an electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by Maxwell's equations. Common phenomena are related to electricity, including lightning, static electricity, electric heating, electric discharges and many others.

The presence of either a positive or negative electric charge produces an electric field. The motion of electric charge carriers is an electric current and produces a magnetic field. In most applications, Coulomb's law determines the force acting on an electrically charged particle. Electric potential is the work done to move an electric charge from one position to another within an electric field, typically measured in volts. (Full article...)
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Roman copy of a Greek bust of Aristotle

Aristotle (Ancient Greek: Ἀριστοτέλης, romanized: Aristotélēs; 384–322 BC) was an ancient Greek philosopher and polymath. His writings span the natural sciences, philosophy, linguistics, economics, politics, psychology, and the arts. As the founder of the Peripatetic school of philosophy in the Lyceum in Athens, he began the wider Aristotelian tradition that followed, which set the groundwork for the development of modern science.

Little is known about Aristotle's life. He was born in the city of Stagira in Chalkidiki (northern Greece) during the Classical period. His father, Nicomachus, died when Aristotle was a child, and he was brought up by a guardian. At around eighteen years old, he joined Plato's Academy in Athens and remained there until the age of thirty seven (c. 347 BC). Shortly after Plato died, Aristotle left Athens and, at the request of Philip II of Macedon, tutored his son Alexander the Great beginning in 343 BC. He established a library in the Lyceum, which helped him to produce many of his hundreds of books on papyrus scrolls. (Full article...)
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In particle physics, quantum electrodynamics (QED) is the relativistic quantum field theory of electrodynamics. In essence, it describes how light and matter interact and is the first theory where full agreement between quantum mechanics and special relativity is achieved. QED mathematically describes all phenomena involving electrically charged particles interacting by means of exchange of photons and represents the quantum counterpart of classical electromagnetism giving a complete account of matter and light interaction.

In technical terms, QED can be described as a perturbation theory of the electromagnetic quantum vacuum. Richard Feynman called it "the jewel of physics" for its extremely accurate predictions of quantities like the anomalous magnetic moment of the electron and the Lamb shift of the energy levels of hydrogen. It is the most precise and stringently tested theory in physics. However, the prediction of vacuum zero energy made by QED has 10^120 magnitude of difference compared to experimental observation value. This is called the cosmological constant problem or vacuum catastrophe. (Full article...)
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"Subtle Is the Lord"—The Science and the Life of Albert Einstein is a biography of Albert Einstein written by Abraham Pais. First published in 1982 by Oxford University Press, the book is one of the most acclaimed biographies of the scientist. This was not the first popular biography of Einstein, but it was the first to focus on his scientific research as opposed to his life as a popular figure. Pais, renowned for his work in theoretical particle physics, was a friend of Einstein's at the Institute for Advanced Study. Originally published in English in the United States and the United Kingdom, the book has translations in over a dozen languages. Pais later released a sequel to the book in 1994 titled Einstein Lived Here and, after his death in 2000, the University Press released a posthumous reprint of the biography in 2005, with a new foreword by Roger Penrose. Considered very popular for a science book, the biography sold tens of thousands of copies of both paperback and hardcover versions in its first year. The book has received many reviews and, the year after its initial publication, it won both the 1983 National Book Award for Nonfiction, in Science (Hardcover), and the 1983 Science Writing Award. (Full article...)
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Franck in 1925

James Franck (German: [ˈdʒɛɪ̯ms ˈfʁaŋk] ; 26 August 1882 – 21 May 1964) was a German–American physicist who shared the 1925 Nobel Prize in Physics with Gustav Hertz "for their discovery of the laws governing the impact of an electron upon an atom."

Franck 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. (Full article...)
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St. Mary's-in-Tuxedo Episcopal Church, otherwise simply referred to as St. Mary's-in-Tuxedo, is an active Episcopal church in Tuxedo, New York, located within the historic village of Tuxedo Park.

Constructed in 1888 according to designs by architect William Appleton Potter, the Shingle style community church was the result of efforts to establish a permanent place of worship for Tuxedo's predominantly Episcopalian residents. The church's interior features the work of architect Bertram Goodhue and sculptor Lee Lawrie, which accompanies the many examples of late 19th- and early 20th-century stained glass produced by prominent artists, including Louis Comfort Tiffany and John La Farge. Later additions to the wider campus include designs by Richard Howland Hunt and James Brown Lord. (Full article...)
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Charles Allen Thomas (February 15, 1900 – March 29, 1982) was a noted American chemist and businessman, and an important figure in the Manhattan Project. He held over 100 patents.

A graduate of Transylvania College and Massachusetts Institute of Technology, Thomas worked as a research chemist at General Motors as part of a team researching antiknock agents. This led to the development of tetraethyllead, which was widely used in motor fuels for many decades until its toxicity led to its prohibition. In 1926, he and Carroll A. "Ted" Hochwalt co-founded Thomas & Hochwalt Laboratories in Dayton, Ohio, with Thomas as president of the company. It was acquired by Monsanto in 1936, and Thomas would spend the rest of his career with Monsanto, rising to become its president in 1950, and chairman of the board from 1960 to 1965. He researched the chemistry of hydrocarbons and polymers, and developed the proton theory of aluminium chloride, which helped explain a variety of chemical reactions, publishing a book on the subject in 1941. (Full article...)
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The maximum sustained wind associated with a tropical cyclone is a common
indicator of the intensity of the storm. Within a mature tropical cyclone, it is found within the eyewall at a certain distance from the center, known as the radius of maximum wind, or RMW. Unlike gusts, the value of these winds are determined via their sampling and averaging the sampled results over a period of time. Wind measuring has been standardized globally to reflect the winds at 10 meters (33 ft) above mean sea level, and the maximum sustained wind represents the highest average wind over either a one-minute (US) or ten-minute time span (see the definition, below), anywhere within the tropical cyclone. Surface winds are highly variable due to friction between the atmosphere and the Earth's surface, as well as near hills and mountains over land.

Over the ocean, satellite imagery is often used to estimate the maximum sustained winds within a tropical cyclone. Land, ship, aircraft reconnaissance observations, and radar imagery can also estimate this quantity, when available. This value helps determine the damage potential of a tropical cyclone, through use of such scales as the Saffir–Simpson scale. (Full article...)

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September anniversaries

6 September 1809 - Sir George Cayley identifies the four aerodynamic forces
3 September 1821 - Faraday discovers electromagnetic rotation (the principle behind the electric motor).
- September 1911 - The Sackur-Tetrode Equation is published in Annalen der Physik.
29 September 1904 - Nature publishes Wood's letter discrediting N-rays.
27 September 1905 - E=mc² --- Annalen der Physik publishes the Mass–Energy equivalence
9 September 1934: The American Rocket Society (ARS) launched Rocket No. 4 to 400 feet.
17 September 1959 - The first powered X-15 flight.
9 September 1959 - The Atlas 10-D rocket is launched.
1 September 1974 - Pioneer 11 sends polar images of Jupiter.
20 September 1979 - The High Energy Astronomical Observatory (HEAO) 3 is launched.
- September 1981 - Invention of the scanning tunneling microscope.

Births

22 September 1791 Michael Faraday (d.1867)
29 September 1901 Enrico Fermi

Deaths

5 September 1906 - Ludwig Boltzmann
7 September 1783 - Leonhard Euler
9 September 2003 - Edward Teller

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General images

The following are images from various physics-related articles on Wikipedia.

Image 1The ancient Greek mathematician Archimedes, developer of ideas regarding fluid mechanics and buoyancy. (from History of physics)
Image 2Marie Skłodowska-Curie
(1867–1934) received Nobel prizes in physics (1903) and chemistry (1911). (from History of physics)
Image 3The first Bose–Einstein condensate observed in a gas of ultracold rubidium atoms. The blue and white areas represent higher density. (from Condensed matter physics)
Image 4Hydrogen emission spectrum is discrete (here in log scale). The lines can only be explained with quantum mechanics. (from History of physics)
$Image 5Image of X-ray diffraction pattern from a protein crystal (from Condensed matter physics)$
Image 5Image of X-ray diffraction pattern from a protein crystal (from Condensed matter physics)
Image 6A 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)
Image 7Ancient Egyptian astronomy is evident in monuments like the ceiling of Senemut's tomb from the Eighteenth Dynasty of Egypt. (from History of physics)
Image 8A page from al-Khwārizmī's Algebra. (from History of physics)
Image 9Classical 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)
Image 10Galileo Galilei (1564–1642), early proponent of the modern scientific worldview and method (from History of physics)
Image 11Richard Feynman's Los Alamos ID badge (from History of physics)
Image 12Classical 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)
Image 13Newton's cannonball, a though experiment by Newton relating the motion of a projectile and orbiting of planets. (from History of physics)
Image 14James Prescott Joule's apparatus for measuring the mechanical equivalent of heat which the "work" of the falling weight is converted into the "heat" of agitation in the water. (from History of physics)
Image 15Chien-Shiung Wu worked on parity violation in 1956 and announced her results in January 1957. (from History of physics)
Image 16Sir Isaac Newton (1642–1727) (from History of physics)
Image 171927 Solvay Conference included prominent physicists Albert Einstein, Werner Heisenberg, Max Planck, Hendrik Lorentz, Niels Bohr, Marie Curie, Erwin Schrödinger, Paul Dirac (from History of physics)
Image 18The quantum Hall effect: Components of the Hall resistivity as a function of the external magnetic field (from Condensed matter physics)
Image 19Crookes tube used to study cathode rays. It led to the discovery of the electron by J. J. Thomson. (from History of physics)
Image 20Heliocentric model proposed in 1543 by Nicolaus Copernicus (from History of physics)
Image 21Torricelli's experiment (from History of physics)
Image 22Albert Einstein (1879–1955), ca. 1905 (from History of physics)
Image 23Aristotle (384–322 BCE) (from History of physics)
Image 24Computer 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)
Image 25Johannes Kepler's first law of planetary motion states that planets move in elliptical orbits about the Sun. (from History of physics)
Image 26Star 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)
Image 27A replica of the first point-contact transistor in Bell labs (from Condensed matter physics)
Image 28Cartesian coordinate system was introduced by René Descartes (from History of physics)
Image 29Leonardo da Vinci (from History of physics)
Image 30Magdeburg hemispheres, an experiment by Otto von Guericke where two metal hemispheres are held together by vacuum and cannot be separated even if large forces are applied. (from History of physics)
Image 31Composite montage comparing Jupiter (left) and its four Galilean moons (from top: Io, Europa, Ganymede, Callisto) (from History of physics)
Image 32Replica of William Herschel's telescope used to discover Uranus (from History of physics)
Image 33The Standard Model (from History of physics)
Image 34An engraving of Benjamin Franklin's kite experiment used to study lightning. (from History of physics)
Image 35Einstein proposed that gravitation results from masses (or their equivalent energies) curving ("bending") the spacetime in which they exist, altering the paths they follow within it. (from History of physics)
Image 36Heike Kamerlingh Onnes and Johannes van der Waals with the helium liquefactor at Leiden in 1908 (from Condensed matter physics)
Image 37The 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)
Image 38Maxwell's demon, thought experiment by James Clerk Maxwell to describe the kinetic theory of gases and describe how a microscopic creature could lead to violations of the second law of thermodynamics. (from History of physics)
Image 39One 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)
Image 40Christiaan Huygens (1629–1695) (from History of physics)
Image 41Ibn al-Haytham (c. 965–1040). (from History of physics)
Image 42A 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 43The Voltaic pile, the first battery was invented by Alessandro Volta in 1800 (from History of physics)

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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.

Fundamental Concepts	Classical Physics	Modern Physics	Cross Discipline Topics
Continuum	Solid Mechanics	Fluid Mechanics	Geophysics
Motion	Classical Mechanics	Analytical mechanics	Mathematical Physics
Kinetics	Kinematics	Kinematic chain	Robotics
Matter	Classical states	Modern states	Nanotechnology
Energy	Chemical Physics	Plasma Physics	Materials Science
Cold	Cryophysics	Cryogenics	Superconductivity
Heat	Heat transfer	Transport Phenomena	Combustion
Entropy	Thermodynamics	Statistical mechanics	Phase transitions
Particle	Particulates	Particle physics	Particle accelerator
Antiparticle	Antimatter	Annihilation physics	Gamma ray
Waves	Oscillation	Quantum oscillation	Vibration
Gravity	Gravitation	Gravitational wave	Celestial mechanics
Vacuum	Pressure physics	Vacuum state physics	Quantum fluctuation
Random	Statistics	Stochastic process	Brownian motion
Spacetime	Special Relativity	General Relativity	Black holes
Quantum	Quantum mechanics	Quantum field theory	Quantum computing
Radiation	Radioactivity	Radioactive decay	Cosmic ray
Light	Optics	Quantum optics	Photonics
Electrons	Solid State	Condensed Matter	Symmetry breaking
Electricity	Electrical circuit	Electronics	Integrated circuit
Electromagnetism	Electrodynamics	Quantum Electrodynamics	Chemical Bonds
Strong interaction	Nuclear Physics	Quantum Chromodynamics	Quark model
Weak interaction	Atomic Physics	Electroweak theory	Radioactivity
Standard Model	Fundamental interaction	Grand Unified Theory	Higgs boson
Information	Information science	Quantum information	Holographic principle
Life	Biophysics	Quantum Biology	Astrobiology
Conscience	Neurophysics	Quantum mind	Quantum brain dynamics
Cosmos	Astrophysics	Cosmology	Observable universe
Cosmogony	Big Bang	Mathematical universe	Multiverse
Chaos	Chaos theory	Quantum chaos	Perturbation theory
Complexity	Dynamical system	Complex system	Emergence
Quantization	Canonical quantization	Loop quantum gravity	Spin foam
Unification	Quantum gravity	String theory	Theory of Everything