Physics

Warning: mkdir() [function.mkdir]: Permission denied in /home/webs/affiliatelib2/CacheManager.php on line 12

Warning: mkdir() [function.mkdir]: No such file or directory in /home/webs/affiliatelib2/CacheManager.php on line 12

Warning: fopen(/home/templatecore2cache//*cluesnet.com/79/7903208c6647a30248f6dfa0f48ac17a83948a2a.tc2cache) [function.fopen]: failed to open stream: No such file or directory in /home/webs/affiliatelib2/CacheManager.php on line 130

Warning: fwrite(): supplied argument is not a valid stream resource in /home/webs/affiliatelib2/CacheManager.php on line 131

Warning: fclose(): supplied argument is not a valid stream resource in /home/webs/affiliatelib2/CacheManager.php on line 132

This is a discussion of a present category of science. For the work by Aristotle, see “Physics (Aristotle)”. For a history of the science, see “History of physics”.

levitating above a high-temperature superconductor demonstrates the Meissner effect.

Physics is the science of matterR. P. Feynman, R. B. Leighton, M. Sands (1963), The Feynman Lectures on Physics, ISBN 0-201-02116-1 Hard-cover. p.1-1 Feynman begins with the atomic theory, 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. ..." vol. I p. I-2and its Motion (physics)James Clerk Maxwell (1876), Matter and Motion. Notes and appendices by Joseph Larmor. "Physical science is that department of knowledge which relates to the order of nature, or, in other words, to the regular succession of events". p.1"Give me matter and motion, and I will construct the universe." --Rene Descartes (1596-1650), as well as space and timehttp://www.fnal.gov/pub/inquiring/matter/index.htmlE.F. Taylor, John Archibald Wheeler (2000), Exploring Black Holes: Introduction to General Relativity, ISBN 0-201-38423-X Hard-cover. Back cover: "Spacetime tells matter how to move; mass tells spacetime how to curve."—the science that deals with concepts such as force, energy, mass, and charge (physics). As an experiment science, its goal is to understand the natural world.H.D. Young & R.A. Freedman, University Physics with Modern Physics: 11th Edition: International Edition (2004), Addison Wesley. Chapter 1, section 1.1, page 2 has this to say: "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."Steve Holzner, Physics for Dummies (2006), Wiley. Chapter 1, page 7 says: "Physics is the study of your world and the world and universe around you." See Amazon Online Reader: Physics For Dummies (For Dummies(Math & Science)), last viewed 24 Nov 2006. For the etymology of the word physics, see physis (φύσις).

In one form or another, physics is one of the oldest academic disciplines; through its modern subfield of astronomy, it may be the oldest of all.Evidence exists that the earliest civilizations dating back to beyond 3000BC, such as the Sumer, Ancient Egyptians, and the Indus Valley Civilization, all had a predictive knowledge and a very basic understanding of the motions of the Sun, Moon, and stars.Sometimes synonymous with philosophy, chemistry and even certain branches of mathematics and biology during the last two millennia, physics Scientific Revolution in the 17th centuryFrancis Bacon (1620), Novum Organum was critical in the history of scientific method.and these disciplines are now generally distinct, although the boundaries remain difficult to define.

Advances in physics often translate to the technological sector, and sometimes influence the other sciences, as well as mathematics and philosophy. For example, advances in the understanding of electromagnetism have led to the widespread use of electrically driven devices (televisions, computers, home appliances etc.); advances in thermodynamics led to the development of motorized transport; and advances in mechanics led to the development of the calculus, quantum chemistry, and the use of instruments like the electron microscope in microbiology.

Today, physics is a broad and highly developed subject. Research is often divided into four subfields: condensed matter physics; atomic, molecular, and optical physics; high energy physics; and astronomy and astrophysics. Most physicists also specialize in either Theoretical physics or Experimental physics research, the former dealing with the development of new theories, and the latter dealing with the experimental testing of theories and the discovery of new phenomena. Despite important discoveries during the last four centuries, there are a number of open questions in physics, and many areas of active research.

Core theories Although physics encompasses a wide variety of phenomena, all competent physicists are familiar with the basic theories of classical mechanics, electromagnetism, relativity, thermodynamics, and quantum mechanics. Each of these theories has been tested in numerous experiments and proven to be an accurate model of nature within its domain of validity. For example, classical mechanics correctly describes the motion of objects in everyday experience, but it breaks down at the atomic scale, where it is superseded by quantum mechanics, and at speeds approaching the speed of light, where special relativity effects become important. While these theories have long been well-understood, they continue to be areas of active research—for example, a remarkable aspect of classical mechanics known as chaos theory was developed in the 20th century, three centuries after the original formulation of mechanics by Isaac Newton (1642–1727). The basic theories form a foundation for the study and research of more specialized topics. A table of these theories, along with many of the concepts they employ, can be found Physics/Theories.

Classical mechanics uses the principle of mechanical advantage so that a small force can lift a heavy weight.

Classical mechanics is a model of the physics of forces acting upon bodies. It is often referred to as "Newtonian mechanics" after Isaac Newton and his Newton's laws of motion. Mechanics is subdivided into statics, which models objects at rest, kinematics, which models objects in motion, and dynamics (mechanics), which models objects subjected to forces. The classical mechanics of continuous and deformable objects is continuum mechanics, which can itself be broken down into solid mechanics and fluid mechanics according to the state of matter being studied. The latter, the mechanics of liquids and gases, includes hydrostatics, hydrodynamics, pneumatics, aerodynamics, and other fields.

Classical mechanics produces very accurate results within the domain of everyday experience. It is superseded by relativity for systems moving at large velocities near the speed of light, quantum mechanics for systems at small distance scales, and relativistic quantum field theory for systems with both properties. Nevertheless, classical mechanics is still very useful, because it is much simpler and easier to apply than these other theories, and it has a very large range of approximate validity. Classical mechanics can be used to describe the motion of human-sized objects (such as tops and baseballs), many astronomical objects (such as planets and galaxies), and certain microscopic objects (such as organic molecules).

An important concept of mechanics is the identification of conserved energy and momentum, which lead to the Lagrangian mechanics and Hamiltonian mechanics reformulations of Newton's laws. Theories such as fluid mechanics and the kinetic theory of gases result from applying classical mechanics to macroscopic systems. A relatively recent result of considerations concerning the dynamics of nonlinear systems is chaos theory, the study of systems in which small changes in a variable may have large effects. Newton's law of universal gravitation, formulated within classical mechanics, explained Kepler's laws of planetary motion and helped make classical mechanics an important element of the Scientific Revolution.

Electromagnetism

Electromagnetism describes the interaction of charged particles with electric and magnetic field (physics)s. It can be divided into electrostatics, the study of interactions between electric charges at rest, and electrodynamics, the study of interactions between moving charges and radiation. The classical theory of electromagnetism is based on the Lorentz force law and Maxwell's equations.

Electrostatics is the study of phenomena associated with charged bodies at rest. As described by Coulomb’s law, such bodies exert forces on each other. Their behavior can be analyzed in terms of the concept of an electric field surrounding any charged body, such that another charged body placed within the field is subject to a force proportional to the magnitude of its own charge and the magnitude of the field at its location. Whether the force is attractive or repulsive depends on the polarity of the charge. Electrostatics has many applications, ranging from the analysis of phenomena such as thunderstorms to the study of the behavior of electron tubes.

Electrodynamics is the study of phenomena associated with charged bodies in motion and varying electric field and magnetic fields. Since a moving charge produces a magnetic field, electrodynamics is concerned with effects such as magnetism, electromagnetic radiation, and electromagnetic induction, including such practical applications as the electric generator and the electric motor. This area of electrodynamics, known as classical electrodynamics, was first systematically explained by James Clerk Maxwell, and Maxwell’s equations describe the phenomena of this area with great generality. A more recent development is quantum electrodynamics, which incorporates the laws of Quantum field theory in order to explain the interaction of electromagnetic radiation with matter. Dirac, Heisenberg, and Pauli were pioneers in the formulation of quantum electrodynamics. Relativistic electrodynamics accounts for special relativity corrections to the motions of charged particles when their speeds approach the speed of light. It applies to phenomena involved with particle accelerators and electron tubes carrying high voltages and currents.

Electromagnetism encompasses various real-world electromagnetic phenomena. For example, light is an oscillating electromagnetic field that is radiated from accelerating charged particles. Aside from gravity, most of the forces in everyday experience are ultimately a result of electromagnetism.

The principles of electromagnetism find applications in various allied disciplines such as microwaves, antennas, electric machines, satellite communications, bioelectromagnetics, plasmas, nuclear research, fiber optics, electromagnetic interference and compatibility, electromechanical energy conversion, radar meteorology, and remote sensing. Electromagnetic devices include transformers, electric relays, radio/TV, telephones, electric motors, transmission lines, waveguides, optical fibers, and lasers.

Relativity space probe (artist's impression): radio signals sent between the Earth and the probe (green wave) are Shapiro effect by the warpage of space and time (blue lines).

Relativity is a generalization of classical mechanics that describes fast-moving or very massive systems. It remains consistent with Maxwell's equations and includes special relativity and general relativity.

The theory of special relativity was proposed in 1905 by Albert Einstein in his article "Annus Mirabilis Papers#Special relativity". It is based on postulates of special relativity: (1) that the mathematical forms of the Physical law are invariant in all inertial frame of reference; and (2) that the speed of light in a vacuum is constant and independent of the source or observer. Reconciling the two postulates requires a unification of space and time into the frame-dependent concept of spacetime.

Special relativity has a variety of surprising consequences that seem to violate common sense, but all have been experimentally verified. It overthrows Newtonian physics by stating that distance and time depend on the observer, and that time and space are perceived differently, depending on the observer. The theory leads to the assertion of change in mass, dimension, and time with increased velocity. It also yields the equivalence of matter and energy, as expressed in the mass-energy equivalence formula E = mc², where c is the speed of light in a vacuum. Special relativity and the Galilean relativity of Newtonian mechanics agree when velocities are small compared to the speed of light. Special relativity does not describe gravitation; however, it can handle accelerated motion in the absence of gravitation.{{Citation ] is the Geometry theory of gravitation published by Albert Einstein in 1915/16. It unifies special relativity, Newton's law of universal gravitation, and the insight that gravitation can be described by the curvature of space and time. In general relativity, the curvature of space-time is produced by the energy of matter and radiation. General relativity is distinguished from other Metric (mathematics) :Category:Theories of gravitation by its use of the Einstein field equations to relate space-time content and space-time curvature. Local Hendrik Lorentz Invariance requires that the manifolds described in GR be 4-dimensional and Lorentzian instead of Riemannian manifold. In addition, the principle of general covariance forces that mathematics be expressed using tensor calculus.

The first success of general relativity was in explaining the anomalous perihelion precession of Mercury (planet). Then in 1919, Arthur Stanley Eddington announced that observations of stars near the eclipsed Sun confirmed general relativity's prediction that massive objects bend light. Since then, many other tests of general relativity have confirmed many of the #Predictions, including gravitational time dilation, the gravitational redshift of light, Shapiro delay, and gravitational radiation. In addition, numerous observations are interpreted as confirming one of general relativity's most mysterious and exotic predictions, the existence of black holes.

Thermodynamics and statistical mechanics - heat moves from hot (boiler) to cold (condenser) and Work (thermodynamics) is extracted

Thermodynamics studies the effects of changes in temperature, pressure, and volume on physical systems at the macroscopic scale, and the transfer of energy as heat. Historically, thermodynamics developed out of need to increase the thermodynamic efficiency of early steam engines.

The starting point for most thermodynamic considerations are the laws of thermodynamics, which postulate that energy can be exchanged between physical systems as heat or Mechanical work. They also postulate the existence of a quantity named entropy, which can be defined for any system. In thermodynamics, interactions between large ensembles of objects are studied and categorized. Central to this are the concepts of System (thermodynamics) and Surroundings (thermodynamics). A system is composed of particles, whose average motions define its properties, which in turn are related to one another through Equation of state. Properties can be combined to express internal energy and thermodynamic potentials, which are useful for determining conditions for Dynamic equilibrium and spontaneous processes.

Statistical mechanics analyzes macroscopic thermodynamic system by applying statistics to their microscopic constituents. It provides a framework for relating the microscopic properties of individual atoms and molecules to the macroscopic or bulk properties of materials that can be observed in everyday life. Thermodynamics can be explained as a natural result of statistics and mechanics (classical and quantum) at the microscopic level. In this way, the gas laws can be derived, from the assumption that a gas is a collection of individual particles, as hard spheres with mass. Conversely, if the individual particles are also considered to have charge, then the individual accelerations of those particles will cause the emission of light. It was these considerations which caused Max Planck to formulate his law of blackbody radiation,Max Planck (1925), A Survey of Physical Theory derives his law of blackbody radiation in the notes on pp. 115-116, ISBN 0-486-67867-9 but only with the assumption that the spectrum of radiation emitted from these particles is not continuous in frequency, but rather quantized.Feynman Lectures on Physics, vol I p. 41-6, ISBN 0-201-02010-6

Quantum mechanics electron orbitals shown as cross-sections with color-coded probability amplitude

Quantum mechanics is the branch of physics treating atomic and subatomic particle systems and their interaction with radiation in terms of observable quantities. It is based on the observation that all forms of energy are released in discrete units or bundles called "quantum". Remarkably, quantum theory typically permits only probability or statistics calculation of the observed features of subatomic particles, understood in terms of wavefunctions. The Schrödinger equation plays the role in quantum mechanics that Newton's laws of motion and conservation of energy serve in classical mechanics—i.e., it predicts the future behavior of a dynamical system—and is a wave equation in terms of the wavefunction which predicts analytically and precisely the probability of events or outcomes.

According to the older theories of classical physics, energy is treated solely as a continuous phenomenon, while matter is assumed to occupy a very specific region of space and to move in a continuous manner. According to the quantum theory, energy is held to be emitted and absorbed in tiny, discrete amounts. An individual bundle or packet of energy, called a quantum (pl. quanta), thus behaves in some situations much like particles of matter; particles are found to exhibit certain wavelike properties when in motion and are no longer viewed as localized in a given region but rather as spread out to some degree. For example, the light or other radiation given off or absorbed by an atom has only certain frequency (or wavelengths), as can be seen from the atomic spectra associated with the chemical element represented by that atom. The quantum theory shows that those frequencies correspond to definite energies of the light quanta, or photons, and result from the fact that the electrons of the atom can have only certain allowed energy values, or levels; when an electron changes from one allowed level to another, a quantum of energy is emitted or absorbed whose frequency is directly proportional to the energy difference between the two levels.

The formalism of quantum mechanics was developed during the 1920s. In 1924, Louis de Broglie proposed that not only do light waves sometimes exhibit particle-like properties, as in the photoelectric effect and atomic spectra, but particles may also exhibit wavelike properties. Two different formulations of quantum mechanics were presented following de Broglie’s suggestion. The wave mechanics of Erwin Schrödinger (1926) involves the use of a mathematical entity, the wave function, which is related to the probability of finding a particle at a given point in space. The matrix mechanics of Werner Heisenberg (1925) makes no mention of wave functions or similar concepts but was shown to be mathematically equivalent to Schrödinger’s theory. A particularly important discovery of the quantum theory is the uncertainty principle, enunciated by Heisenberg in 1927, which places an absolute theoretical limit on the accuracy of certain measurements; as a result, the assumption by earlier scientists that the physical state of a system could be measured exactly and used to predict future states had to be abandoned. Quantum mechanics was combined with the theory of relativity in the formulation of Paul Dirac (1928), which, in addition, predicted the existence of antiparticles. Other developments of the theory include quantum statistics, presented in one form by Einstein and Satyendranath Bose (the Bose-Einstein statistics) and in another by Dirac and Enrico Fermi (the Fermi-Dirac statistics); quantum electrodynamics, concerned with interactions between charged particles and electromagnetic fields; its generalization, quantum field theory; and quantum electronics. The discovery of quantum mechanics in the early 20th century revolutionized physics, and quantum mechanics is fundamental to most areas of current research.

Research Theory and experiment The culture of physics research differs from most sciences in the separation of theory and experiment. Since the twentieth century, most individual physicists have specialized in either theoretical physics or experimental physics. The great Italy physicist Enrico Fermi (1901–1954), who made fundamental contributions to both theory and experimentation in nuclear physics, was a notable exception. In contrast, almost all the successful theorists in biology and chemistry (e.g. American quantum chemistry and biochemistry Linus Pauling) have also been experimentalists, although this is changing as of late.

Theorists seek to develop mathematical models that both agree with existing experiments and successfully predict future results, while experimentalists devise and perform experiments to test theoretical predictions and explore new phenomena. Although theory and experiment are developed separately, they are strongly dependent upon each other. Progress in physics frequently comes about when experimentalists make a discovery that existing theories cannot explain, or when new theories generate experimentally testable predictions. Theorists working closely with experimentalists frequently employ Phenomenology (science).

Theoretical physics is closely related to mathematics, which provides the language of physical theories, and large areas of mathematics, such as calculus, have been invented specifically to solve problems in physics. Theorists may also rely on numerical analysis and simulation#computer simulation, which play an ever richer role in the formulation of physical models. The fields of mathematical physics and computational physics are active areas of research. Theoretical physics has historically rested on philosophy and metaphysics; electromagnetism was unified this waySee, for example, the influence of Immanuel Kant and Johann Wilhelm Ritter on Hans Christian Ørsted.. Thus physicists may speculate with multidimensional spaces and Many-worlds interpretation, and from this, hypothesize theories.

Experimental physics informs, and is informed by, engineering and technology. Experimental physicists involved in basic research design and perform experiments with equipment such as particle accelerators and lasers, whereas those involved in applied research often work in industry, developing technologies such as MRI and transistors. Feynman has noted that experimentalists may seek areas which are not well explored by theorists.

Research fields Contemporary research in physics can be broadly divided into condensed matter physics; atomic, molecular, and optical physics; particle physics; and astrophysics. Since the twentieth century, the individual fields of physics have become increasingly specialization, and today most physicists work in a single field for their entire careers. "Universalists" such as Albert Einstein (1879–1955) and Lev Landau (1908–1968), who worked in multiple fields of physics, are now very rareYet, universalism is encouraged in the culture of physics. For example, the World Wide Web, which was innovated at CERN by Tim Berners-Lee, was created in service to the computer infrastructure of CERN, and was/is intended for use by physicists worldwide. The same might be said for arXiv.org. A table of the major fields of physics, along with their subfields and the theories they employ can be found Physics/Subfields.

Condensed matter atoms, confirming the discovery of a new phase of matter, the Bose–Einstein condensate

Condensed matter physics is the field of physics that deals with the macroscopic physical properties of matter. In particular, it is concerned with the "condensed" phase (matter) that appear whenever the number of constituents in a system is extremely large and the interactions between the constituents are strong. The most familiar examples of condensed phases are Solid-state physics and liquids, which arise from the bonding and electromagnetic force between atoms. More exotic condensed phases include the superfluid and the Bose-Einstein condensate found in certain atomic systems at very low temperatures, the superconductivity phase exhibited by conduction electrons in certain materials, and the ferromagnetic and antiferromagnetic phases of spin (physics)s on crystal lattice.

Condensed matter physics is by far the largest field of contemporary physics. Much progress has also been made in theoretical condensed matter physics. By one estimate, one third of all American physicists identify themselves as condensed matter physicists. Historically, condensed matter physics grew out of solid-state physics, which is now considered one of its main subfields. The term condensed matter physics was apparently coined by Philip Warren Anderson when he renamed his research group—previously solid-state theory—in 1967. In 1978, the Division of Solid State Physics at the American Physical Society was renamed as the Division of Condensed Matter Physics. Condensed matter physics has a large overlap with chemistry, materials science, nanotechnology and engineering.

Atomic, molecular, and optical on an optical table.

Atomic, Molecule, and Optics physics (AMO) is the study of matter-matter and light-matter interactions on the scale of single atoms or structures containing a few atoms. The three areas are grouped together because of their interrelationships, the similarity of methods used, and the commonality of the energy scales that are relevant. All three areas include both classical physics and quantum physics treatments; they can treat their subject from a microscopic view (in contrast to a macroscopic view).

Atomic physics studies the electron hull of atoms. Current research focuses on activities in quantum control, cooling and trapping of atoms and ions, low-temperature collision dynamics, the collective behavior of atoms in weakly interacting gases (Bose-Einstein Condensates and dilute Fermi degenerate systems), precision measurements of fundamental constants, and the effects of electron correlation on structure and dynamics. Atomic physics is influenced by the nucleus (see, e.g., hyperfine splitting), but intra-nuclear phenomenon such as nuclear fission and nuclear fusion are considered part of high energy physics.

Molecular physics focuses on multi-atomic structures and their internal and external interactions with matter and light. Optical physics is distinct from optics in that it tends to focus not on the control of classical light fields by macroscopic objects, but on the fundamental properties of optical fields and their interactions with matter in the microscopic realm.

High energy/Particle Physics detector for the Large Hadron Collider, which physicists hope will detect the Higgs boson of the Standard Model.

Particle physics is the study of elementary particle constituents of matter and radiation, and the interactions between them. It is also called "high energy physics", because many elementary particles do not occur under normal circumstances in nature, but can be created and detected during energetic collisions of other particles, as is done in particle accelerators.

The current state of the classification of elementary particles is the Standard Model. It describes the strong nuclear force, weak nuclear force, and electromagnetism fundamental forces, using mediating gauge bosons. The species of gauge bosons are the gluons, W boson and Z bosons, and the photon, respectively. The model also contains 24 fundamental particles (12 particle/anti-particle pairs), which are the constituents of matter. Finally, it predicts the existence of a type of boson known as the Higgs boson, which has yet to be discovered.

Astrophysics , the Hubble Ultra Deep Field

Astrophysics and astronomy are the application of the theories and methods of physics to the study of stellar structure, stellar evolution, the origin of the solar system, and related problems of Physical cosmology. Because astrophysics is a very broad subject, astrophysicists typically apply many disciplines of physics, including mechanics, electromagnetism, statistical mechanics, thermodynamics, quantum mechanics, relativity, nuclear and particle physics, and atomic and molecular physics.

Astrophysics developed from the ancient science of astronomy. Astronomers of early civilizations performed methodical observations of the night sky, and astronomical artifacts have been found from much earlier periods. After centuries of developments by Babylonian and Greek astronomers, western astronomy lay dormant for fourteen centuries until Nicolaus Copernicus modified the Ptolemaic system by placing the sun at the center of the universe. Tycho Brahe's detailed observations led to Kepler's laws of planetary motion, and Galileo's telescope helped the discipline develop into a modern science. Isaac Newton's theory of universal gravitation provided a physical, dynamic basis for Kepler's laws. By the early 19th cent., the science of celestial mechanics had reached a highly developed state at the hands of Leonhard Euler, Joseph Louis Lagrange, Pierre Simon de Laplace, and others. Powerful new mathematical techniques allowed solution of most of the remaining problems in classical gravitational theory as applied to the solar system. At the end of the 19th century, the discovery of spectral lines in sunlight proved that the chemical elements found in the Sun were also found on Earth. Interest shifted from determining the positions and distances of stars to studying their physical composition (see stellar structure and stellar evolution). Because the application of physics to astronomy became increasingly important throughout the 20th century, the distinction between astronomy and astrophysics has faded.

Physical cosmology is the study of the formation and evolution of the universe on its largest scales. Albert Einstein’s theory of relativity plays a central role in all modern cosmological theories. In the early 20th century, Hubble's discovery that the universe was expanding, as shown by the Hubble diagram, prompted rival explanations known as the steady state universe and the Big Bang. The Big Bang was confirmed by the success of Big Bang nucleosynthesis and the discovery of the cosmic microwave background in 1964. The Big Bang model rests on two theoretical pillars: Albert Einstein's general relativity and the cosmological principle. Cosmologists have recently established a Lambda-CDM model of the evolution of the universe, which include cosmic inflation, dark energy and dark matter.

The discovery by Karl Jansky in 1931 that radio signals were emitted by celestial bodies initiated the science of radio astronomy. Most recently, the frontiers of astronomy have been expanded by space exploration. Perturbations and interference from the earth’s atmosphere make space-based observations necessary for infrared astronomy, ultraviolet astronomy, gamma-ray astronomy, and X-ray astronomy. The Hubble Space Telescope, launched in 1990, has made possible visual observations of a quality far exceeding those of earthbound instruments; earth-bound observatories using telescopes with adaptive optics will now be able to compensate for the turbulence of Earth's atmosphere.

Applied physics Applied physics is a general term for physics which is intended for a particular Utility. Applied is distinguished from pure by a subtle combination of factors such as the motivation and attitude of researchers and the nature of the relationship to the technology or science that may be affected by the work. Stanford Applied Physics Department Description It usually differs from engineering in that an applied physicist may not be designing something in particular, but rather is using physics or conducting physics research with the aim of developing new technologies or solving a problem. The approach is similar to that of applied mathematics. Applied physicists can also be interested in the use of physics for scientific research. For instance, people working on accelerator physics might seek to build better particle detectors for research in theoretical physics.

Physics is used heavily in engineering. For example, statics, a subfield of mechanics, is used in the building of bridges or other structures, while acoustics is used to design better concert halls. An understanding of physics is important to the design of realistic flight simulators, video games, and movies.

Notes Further reading

A large number of textbooks, popular books, and webpages about physics are available for Physics (further reading).
List of important publications in physics

Organizations

AIP.org is the website of the American Institute of Physics
IOP.org is the website of the Institute of Physics
APS.org is the website of the American Physical Society
SPS National is the website of the American Society of Physics Students
CAP.ca is the website of the Canadian Association of Physicists
EPS.org is the website of the European Physical Society

physics.org | Home
Your guide to physics on the web. Physics.org is the place to be if you have a burning physics question, or if you just want to browse articles and interactive features about ...

School of Physics - School of Physics & Astronomy - The University of ...
Research in the School is organised within the general areas of Astronomy, Magnetic Resonance Imaging, Nanoscience, Quantum and Statistical Phenomena and Semiconductors.

Bristol University Physics - Department of Physics
Includes a staff list and contact information, course details and list of students, admissions information and information on the research groups.

The University of Oxford Physics Department Home Page
A source of information on admissions, teaching and research at one of the largest departments in the United Kingdom.

Physics
Information of colloquia, seminars, research, staff and both undergraduate and post-graduate degree programmes.

BBC - GCSE Bitesize - Science: Physics
A secondary school revision resource for GCSE Science:Physics ... RU Revising science? Find out if you can fool ten people that you are.

Department of Physics - Durham University
General departmental information, admissions, research, and course work.

Department of Physics & Astronomy
Includes information on the research groups and courses offered, an introduction to the department, and details of colloquia.

UCL Physics & Astronomy
Information grouped under admissions, people, teaching and research.

Department of Physics, Cavendish Laboratory
The department of physics at cambridge is known for the quality of its research and teaching. Details of both are given here.