| natural philosophy | | |
| n. (cognition) | 1. natural philosophy, physics | the science of matter and energy and their interactions.; "his favorite subject was physics" |
| ~ phase space | (physics) an ideal space in which the coordinate dimensions represent the variables that are required to describe a system or substance.; "a multidimensional phase space" |
| ~ containment | (physics) a system designed to prevent the accidental release of radioactive material from a reactor. |
| ~ hodoscope | (physics) scientific instrument that traces the path of a charged particle. |
| ~ magnet | (physics) a device that attracts iron and produces a magnetic field. |
| ~ meniscus | (physics) the curved upper surface of a nonturbulent liquid in a vertical tube. |
| ~ nuclear reactor, reactor | (physics) any of several kinds of apparatus that maintain and control a nuclear reaction for the production of energy or artificial elements. |
| ~ metastability | the quality of a physical system that persists in its existing equilibrium when undisturbed (or only slightly disturbed) but able to pass to a more stable equilibrium when sufficiently disturbed. |
| ~ isotropy, symmetry | (physics) the property of being isotropic; having the same value when measured in different directions. |
| ~ wave-particle duality, duality | (physics) the property of matter and electromagnetic radiation that is characterized by the fact that some properties can be explained best by wave theory and others by particle theory. |
| ~ absorption factor, absorptivity | (physics) the property of a body that determines the fraction of the incident radiation or sound flux absorbed or absorbable by the body. |
| ~ reluctivity | (physics) the resistance of a material to the establishment of a magnetic field in it. |
| ~ rest mass | (physics) the mass of a body as measured when the body is at rest relative to an observer, an inherent property of the body. |
| ~ relativistic mass | (physics) the mass of a body in motion relative to the observer: it is equal to the rest mass multiplied by a factor that is greater than 1 and that increases as the magnitude of the velocity increases. |
| ~ gravitational mass | (physics) the mass of a body as measured by its gravitational attraction for other bodies. |
| ~ inertial mass | (physics) the mass of a body as determined by the second law of motion from the acceleration of the body when it is subjected to a force that is not due to gravity. |
| ~ mass energy | (physics) the mass of a body regarded relativistically as energy. |
| ~ flux density, flux | (physics) the number of changes in energy flow across a given surface per unit area. |
| ~ absorbance, optical density, photographic density, transmission density | (physics) a measure of the extent to which a substance transmits light or other electromagnetic radiation. |
| ~ quantum | (physics) the smallest discrete quantity of some physical property that a system can possess (according to quantum theory). |
| ~ attracter, attractor | (physics) a point in the ideal multidimensional phase space that is used to describe a system toward which the system tends to evolve regardless of the starting conditions of the system. |
| ~ bose-einstein statistics | (physics) statistical law obeyed by a system of particles whose wave function is not changed when two particles are interchanged (the Pauli exclusion principle does not apply). |
| ~ dalton's law of partial pressures, law of partial pressures, dalton's law | (chemistry and physics) law stating that the pressure exerted by a mixture of gases equals the sum of the partial pressures of the gases in the mixture; the pressure of a gas in a mixture equals the pressure it would exert if it occupied the same volume alone at the same temperature. |
| ~ boltzmann distribution law, maxwell-boltzmann distribution law | (physics) a law expressing the distribution of energy among the molecules of a gas in thermal equilibrium. |
| ~ fermi-dirac statistics | (physics) law obeyed by a systems of particles whose wave function changes when two particles are interchanged (the Pauli exclusion principle applies). |
| ~ charles's law, gay-lussac's law, law of volumes | (physics) the density of an ideal gas at constant pressure varies inversely with the temperature. |
| ~ hooke's law | (physics) the principle that (within the elastic limit) the stress applied to a solid is proportional to the strain produced. |
| ~ kirchhoff's laws | (physics) two laws governing electric networks in which steady currents flow: the sum of all the currents at a point is zero and the sum of the voltage gains and drops around any closed circuit is zero. |
| ~ law of gravitation, newton's law of gravitation | (physics) the law that states any two bodies attract each other with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them. |
| ~ law of thermodynamics | (physics) a law governing the relations between states of energy in a closed system. |
| ~ mass-energy equivalence | (physics) the principle that a measured quantity of mass is equivalent (according to relativity theory) to a measured quantity of energy. |
| ~ planck's law | (physics) the basis of quantum theory; the energy of electromagnetic waves is contained in indivisible quanta that have to be radiated or absorbed as a whole; the magnitude is proportional to frequency where the constant of proportionality is given by Planck's constant. |
| ~ planck's radiation law | (physics) an equation that expresses the distribution of energy in the radiated spectrum of an ideal black body. |
| ~ gravitational theory, newton's theory of gravitation, theory of gravitation, theory of gravity | (physics) the theory that any two particles of matter attract one another with a force directly proportional to the product of their masses and inversely proportional to the square of the distance between them. |
| ~ principle of relativity | (physics) a universal law that states that the laws of mechanics are not affected by a uniform rectilinear motion of the system of coordinates to which they are referred. |
| ~ principle of equivalence | (physics) the principle that an observer has no way of distinguishing whether his laboratory is in a uniform gravitational field or is in an accelerated frame of reference. |
| ~ field theory | (physics) a theory that explains a physical phenomenon in terms of a field and the manner in which it interacts with matter or with other fields. |
| ~ natural science | the sciences involved in the study of the physical world and its phenomena. |
| ~ astronomy, uranology | the branch of physics that studies celestial bodies and the universe as a whole. |
| ~ aeronautics, astronautics | the theory and practice of navigation through air or space. |
| ~ biophysics | physics as applied to biological problems. |
| ~ cryogenics, cryogeny | the branch of physics that studies the phenomena that occur at very low temperatures. |
| ~ crystallography | the branch of science that studies the formation and structure of crystals. |
| ~ electromagnetics, electromagnetism | the branch of physics concerned with electromagnetic phenomena. |
| ~ electronics | the branch of physics that deals with the emission and effects of electrons and with the use of electronic devices. |
| ~ electrostatics | the branch of physics that deals with static electricity. |
| ~ mechanics | the branch of physics concerned with the motion of bodies in a frame of reference. |
| ~ atomic physics, nuclear physics, nucleonics | the branch of physics that studies the internal structure of atomic nuclei. |
| ~ optics | the branch of physics that studies the physical properties of light. |
| ~ high-energy physics, high energy physics, particle physics | the branch of physics that studies subatomic particles and their interactions. |
| ~ plasma physics | the branch of physics concerned with matter in its plasma phase. |
| ~ quantum physics | the branch of physics based on quantum theory. |
| ~ rheology | the branch of physics that studies the deformation and flow of matter. |
| ~ bohr theory | (physics) a theory of atomic structure that combined Rutherford's model with the quantum theory; electrons orbiting a nucleus can only be in certain stationary energy states and light is emitted when electrons jump from one energy state to another. |
| ~ conservation | (physics) the maintenance of a certain quantities unchanged during chemical reactions or physical transformations. |
| ~ conservation of parity, mirror symmetry, space-reflection symmetry, parity | (physics) parity is conserved in a universe in which the laws of physics are the same in a right-handed system of coordinates as in a left-handed system. |
| ~ undulatory theory, wave theory, wave theory of light | (physics) the theory that light is transmitted as waves. |
| ~ corpuscular theory, corpuscular theory of light | (physics) the theory that light is transmitted as a stream of particles. |
| ~ kinetic theory, kinetic theory of gases | (physics) a theory that gases consist of small particles in random motion. |
| ~ einstein's theory of relativity, relativity, relativity theory, theory of relativity | (physics) the theory that space and time are relative concepts rather than absolute concepts. |
| ~ supersymmetry | (physics) a theory that tries to link the four fundamental forces.; "according to supersymmetry each force emerged separately during the big bang" |
| ~ quantum theory | (physics) a physical theory that certain properties occur only in discrete amounts (quanta). |
| ~ solid-state physics | the branch of physics that studies the properties of materials in the solid state: electrical conduction in crystals of semiconductors and metals; superconductivity; photoconductivity. |
| ~ statistical mechanics | the branch of physics that makes theoretical predictions about the behavior of macroscopic systems on the basis of statistical laws governing its component particles. |
| ~ thermodynamics | the branch of physics concerned with the conversion of different forms of energy. |
| ~ dynamical system | (physics) a phase space together with a transformation of that space. |
| ~ chaos | (physics) a dynamical system that is extremely sensitive to its initial conditions. |
| ~ collision, hit | (physics) a brief event in which two or more bodies come together.; "the collision of the particles resulted in an exchange of energy and a change of direction" |
| ~ gravitation wave, gravity wave | (physics) a wave that is hypothesized to propagate gravity and to travel at the speed of light. |
| ~ oscillation, vibration | (physics) a regular periodic variation in value about a mean. |
| ~ undulation, wave | (physics) a movement up and down or back and forth. |
| ~ solitary wave, soliton, soliton wave | (physics) a quantum of energy or quasiparticle that can be propagated as a traveling wave in nonlinear systems and is neither preceded nor followed by another such disturbance; does not obey the superposition principle and does not dissipate.; "soliton waves can travel long distances with little loss of energy or structure" |
| ~ transient | (physics) a short-lived oscillation in a system caused by a sudden change of voltage or current or load. |
| ~ quantum jump | (physics) an abrupt transition of an electron or atom or molecule from one quantum state to another with the emission or absorption of a quantum. |
| ~ recombination | (physics) a combining of charges or transfer of electrons in a gas that results in the neutralization of ions; important for ions arising from the passage of high-energy particles. |
| ~ transmutation | (physics) the change of one chemical element into another (as by nuclear decay or radioactive bombardment).; "the transmutation of base metals into gold proved to be impossible" |
| ~ amplitude | (physics) the maximum displacement of a periodic wave. |
| ~ node | (physics) the point of minimum displacement in a periodic system. |
| ~ antinode | (physics) the point of maximum displacement in a periodic system. |
| ~ center of buoyancy, center of immersion, centre of buoyancy, centre of immersion | (physics) the center of mass of the immersed part of ship or other floating object. |
| ~ wavefront, wave front | (physics) an imaginary surface joining all points in space that are reached at the same instant by a wave propagating through a medium. |
| ~ couple | (physics) something joined by two equal and opposite forces that act along parallel lines. |
| ~ elementary particle, fundamental particle | (physics) a particle that is less complex than an atom; regarded as constituents of all matter. |
| ~ quark | (physics) hypothetical truly fundamental particle in mesons and baryons; there are supposed to be six flavors of quarks (and their antiquarks), which come in pairs; each has an electric charge of +2/3 or -1/3.; "quarks have not been observed directly but theoretical predictions based on their existence have been confirmed experimentally" |
| ~ weakly interacting massive particle, wimp | a hypothetical subatomic particle of large mass that interacts weakly with ordinary matter through gravitation; postulated as a constituent of the dark matter of the universe. |
| ~ physicist | a scientist trained in physics. |
| ~ coriolis effect | (physics) an effect whereby a body moving in a rotating frame of reference experiences the Coriolis force acting perpendicular to the direction of motion and to the axis of rotation; on Earth the Coriolis effect deflects moving bodies to the right in the northern hemisphere and to the left in the southern hemisphere. |
| ~ perturbation | (physics) a secondary influence on a system that causes it to deviate slightly. |
| ~ atomic spectrum | (physics) a spectrum of radiation caused by electron transitions within an atom; the series of spectrum lines is characteristic of the element. |
| ~ cohesion | (physics) the intermolecular force that holds together the molecules in a solid or liquid. |
| ~ coriolis force | (physics) a force due to the earth's rotation; acts on a body in motion (airplane or projectile) in a rotating reference frame; in a rotating frame of reference Newton's second law of motion can be made to apply if in addition to the real forces acting on a body a Coriolis force and a centrifugal force are introduced. |
| ~ energy, free energy | (physics) a thermodynamic quantity equivalent to the capacity of a physical system to do work; the units of energy are joules or ergs.; "energy can take a wide variety of forms" |
| ~ power | (physics) the rate of doing work; measured in watts (= joules/second). |
| ~ work | (physics) a manifestation of energy; the transfer of energy from one physical system to another expressed as the product of a force and the distance through which it moves a body in the direction of that force.; "work equals force times distance" |
| ~ force | (physics) the influence that produces a change in a physical quantity.; "force equals mass times acceleration" |
| ~ gravitation, gravitational attraction, gravitational force, gravity | (physics) the force of attraction between all masses in the universe; especially the attraction of the earth's mass for bodies near its surface.; "the more remote the body the less the gravity"; "the gravitation between two bodies is proportional to the product of their masses and inversely proportional to the square of the distance between them"; "gravitation cannot be held responsible for people falling in love" |
| ~ inertia | (physics) the tendency of a body to maintain its state of rest or uniform motion unless acted upon by an external force. |
| ~ angular acceleration | (physics) the rate of change of the angular velocity of a rotating body. |
| ~ angular velocity | (physics) the rate of change of the angular position of a rotating body; usually expressed in radians per second or radians per minute. |
| ~ light, visible light, visible radiation | (physics) electromagnetic radiation that can produce a visual sensation.; "the light was filtered through a soft glass window" |
| ~ sympathetic vibration | (physics) vibration produced by resonance. |
| ~ magnetic dipole moment | (physics) a current loop gives rise to a magnetic field characteristic of a magnetic dipole.; "An orbiting electron in an atom will have a magnetic dipole moment" |
| ~ reluctance | (physics) opposition to magnetic flux (analogous to electric resistance). |
| ~ scintillation | (physics) a flash of light that is produced in a phosphor when it absorbs a photon or ionizing particle. |
| ~ shear | (physics) a deformation of an object in which parallel planes remain parallel but are shifted in a direction parallel to themselves.; "the shear changed the quadrilateral into a parallelogram" |
| ~ stress | (physics) force that produces strain on a physical body.; "the intensity of stress is expressed in units of force divided by units of area" |
| ~ tension | (physics) a stress that produces an elongation of an elastic physical body.; "the direction of maximum tension moves asymptotically toward the direction of the shear" |
| ~ strain | (physics) deformation of a physical body under the action of applied forces. |
| ~ fundamental interaction, interaction | (physics) the transfer of energy between elementary particles or between an elementary particle and a field or between fields; mediated by gauge bosons. |
| ~ color force, strong force, strong interaction | (physics) the interaction that binds protons and neutrons together in the nuclei of atoms; mediated by gluons. |
| ~ weak force, weak interaction | (physics) an interaction between elementary particles involving neutrinos or antineutrinos that is responsible for certain kinds of radioactive decay; mediated by intermediate vector bosons. |
| ~ absorption | (physics) the process in which incident radiated energy is retained without reflection or transmission on passing through a medium.; "the absorption of photons by atoms or molecules" |
| ~ diffusion | (physics) the process in which there is movement of a substance from an area of high concentration of that substance to an area of lower concentration. |
| ~ nuclear reaction | (physics) a process that alters the energy or structure or composition of atomic nuclei. |
| ~ relaxation behavior, relaxation | (physics) the exponential return of a system to equilibrium after a disturbance. |
| ~ spallation | (physics) a nuclear reaction in which a bombarded nucleus breaks up into many particles.; "some astronomers believe that the solar system was formed by spallation when the sun was a very young star" |
| ~ modulus | (physics) a coefficient that expresses how much of a specified property is possessed by a specified substance. |
| ~ coefficient of elasticity, elastic modulus, modulus of elasticity | (physics) the ratio of the applied stress to the change in shape of an elastic body. |
| ~ gas constant, universal gas constant, r | (physics) the universal constant in the gas equation: pressure times volume = R times temperature; equal to 8.3143 joules per kelvin per mole. |
| ~ constant of gravitation, gravitational constant, universal gravitational constant, g | (physics) the universal constant relating force to mass and distance in Newton's law of gravitation. |
| ~ metric, metric function | a function of a topological space that gives, for any two points in the space, a value equal to the distance between them. |
| ~ abundance | (physics) the ratio of the number of atoms of a specific isotope of an element to the total number of isotopes present. |
| ~ pencil | a figure formed by a set of straight lines or light rays meeting at a point. |
| ~ angle of dip, magnetic dip, magnetic inclination, dip, inclination | (physics) the angle that a magnetic needle makes with the plane of the horizon. |
| ~ ground state | (physics) the lowest energy state of an atom or other particle. |
| ~ absorber | (physics) material in a nuclear reactor that absorbs radiation. |
| ~ atom | (physics and chemistry) the smallest component of an element having the chemical properties of the element. |
| ~ molecule | (physics and chemistry) the simplest structural unit of an element or compound. |
| ~ acceleration | (physics) a rate of increase of velocity. |
| ~ deceleration | (physics) a rate of decrease in velocity. |
| ~ bombard | direct high energy particles or radiation against. |
| ~ backscatter | scatter (radiation) by the atoms of the medium through which it passes. |
| ~ transform | increase or decrease (an alternating current or voltage). |
| ~ transform | convert (one form of energy) to another.; "transform energy to light" |
| ~ decay, decompose, disintegrate | lose a stored charge, magnetic flux, or current.; "the particles disintegrated during the nuclear fission process" |
| ~ disintegrate | cause to undergo fission or lose particles. |
| ~ magnetize, magnetise | make magnetic.; "The strong magnet magnetized the iron shavings" |
| ~ degauss, demagnetise, demagnetize | make nonmagnetic; take away the magnetic properties (of).; "demagnetize the iron shavings"; "they degaussed the ship" |
| ~ quench | reduce the degree of (luminescence or phosphorescence) in (excited molecules or a material) by adding a suitable substance. |
| ~ flux, liquify, liquefy | become liquid or fluid when heated.; "the frozen fat liquefied" |
| ~ liquidise, liquify, liquefy, liquidize | make (a solid substance) liquid, as by heating.; "liquefy the silver" |
| ~ solidify | become solid.; "The metal solidified when it cooled" |
| ~ solidify | make solid or more solid; cause to solidify. |
| ~ freeze down, freeze out, freeze | change from a liquid to a solid when cold.; "Water freezes at 32 degrees Fahrenheit" |
| ~ crystalise, crystalize, crystallise, crystallize | cause to form crystals or assume crystalline form.; "crystallize minerals" |
| ~ decouple | eliminate airborne shock waves from (an explosive). |
| ~ polarise, polarize | cause to vibrate in a definite pattern.; "polarize light waves" |
| ~ electrify | charge (a conductor) with electricity. |
| ~ depolarise, depolarize | eliminate the polarization of. |
| ~ shear | become deformed by forces tending to produce a shearing strain. |
| ~ quantise, quantize | apply quantum theory to; restrict the number of possible values of (a quantity) or states of (a physical entity or system) so that certain variables can assume only certain discrete magnitudes that are integral multiples of a common factor.; "Quantize gravity" |
| ~ induct, induce | produce electric current by electrostatic or magnetic processes. |
| ~ translate | subject to movement in which every part of the body moves parallel to and the same distance as every other point on the body. |
| ~ attractive | having the properties of a magnet; the ability to draw or pull.; "an attractive force" |
| ~ repulsive | possessing the ability to repel.; "a repulsive force" |
| ~ reversible | capable of assuming or producing either of two states.; "a reversible chemical reaction"; "a reversible cell" |
| ~ uncharged | of a particle or body or system; having no charge.; "an uncharged particle"; "an uncharged battery" |
| ~ miscible, mixable | (chemistry, physics) capable of being mixed. |
| ~ immiscible, non-miscible, unmixable | (chemistry, physics) incapable of mixing. |
| ~ critical | at or of a point at which a property or phenomenon suffers an abrupt change especially having enough mass to sustain a chain reaction.; "a critical temperature of water is 100 degrees C--its boiling point at standard atmospheric pressure"; "critical mass"; "go critical" |
| ~ noncritical | not critical; not at a point of abrupt change. |
| ~ diabatic | involving a transfer of heat.; "a diabatic process" |
| ~ adiabatic | occurring without loss or gain of heat.; "adiabatic expansion" |
| ~ viscoelastic | having viscous as well as elastic properties. |
| ~ fissile, fissionable | capable of undergoing nuclear fission.; "a fissionable nucleous"; "fissionable material" |
| ~ nonfissionable | not capable of undergoing fission. |
| ~ free | unconstrained or not chemically bound in a molecule or not fixed and capable of relatively unrestricted motion.; "free expansion"; "free oxygen"; "a free electron" |
| ~ bound | held with another element, substance or material in chemical or physical union. |
| ~ identical | having properties with uniform values along all axes. |
| ~ aeolotropic, eolotropic | having properties with different values along different axes. |
| ~ reactive | participating readily in reactions.; "sodium is a reactive metal"; "free radicals are very reactive" |
| ~ activated, excited | (of e.g. a molecule) made reactive or more reactive. |
| ~ unreactive | (chemistry) not reacting chemically. |
| ~ hyperfine | extremely fine or thin, as in a spectral line split into two or more components.; "hyperfine structure" |
| ~ relativistic | relating or subject to the special or the general theory of relativity.; "relativistic quantum mechanics"; "relativistic increase in mass"; "radiation from relativistic particles" |
| ~ fiducial | used as a fixed standard of reference for comparison or measurement.; "a fiducial point" |
| ~ nuclear | of or relating to or constituting the nucleus of an atom.; "nuclear physics"; "nuclear fission"; "nuclear forces" |
| ~ metastable | (of physical systems) continuing in its present state of equilibrium unless sufficiently disturbed to pass to a more stable state of equilibrium. |
| ~ quantal, quantized | of or relating to a quantum or capable of existing in only one of two states. |
| ~ dynamic | of or relating to dynamics. |
| ~ hydrodynamic | of or relating to hydrodynamics. |
| ~ aerodynamic | of or relating to aerodynamics. |
| ~ rheologic, rheological | of or relating to rheology. |
| ~ mesic, mesonic | of or pertaining to a meson.; "the radii of the mesic orbits" |
| ~ reversibly | in a reversible manner.; "reversibly convertible" |
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