#physical_phenomenon  a natural phenomenon involving the physics of matter and energy
  supertype:  natural_phenomenon__naturalphenomenon  all non-artificial phenomena
  subtype:  atmospheric_phenomenon__atmosphericphenomenon  a physical phenomenon associated with the atmosphere
     subtype:  cloud.atmospheric_phenomenon  a visible mass of water or ice particles suspended at a considerable altitude
        subtype:  cirrocumulus_cloud__cirrocumulus  a cloud at a high altitude consisting of a series of regularly arranged small clouds resembling ripples
        subtype:  cirrostratus_cloud__cirrostratus  a thin uniform layer of hazy cloud at high altitude
        subtype:  cirrus_cloud__cirrus  a wispy white cloud (usually of fine ice crystals) at a high altitude (4 to 8 miles)
           subtype:  mare's_tail  a long narrow flowing cirrus cloud
        subtype:  cloud_bank__cloudbank  a layer of clouds seen from a distance
        subtype:  contrail__condensation_trail  an artificial cloud created by an aircraft; caused either by condensation due to the reduction in air pressure above the wing surface or by water vapor in the engine exhaust
        subtype:  cumulonimbus_cloud__cumulonimbus__thundercloud  a dark cloud of great vertical extent charged with electricity; associated with thunderstorms
        subtype:  cumulus_cloud__cumuluscloud__cumulus__cumulu  a globular cloud
           subtype:  altocumulus_cloud__altocumuluscloud__altocumulus__altocumulu  a cumulus cloud at an intermediate altitude of 2 or 3 miles
        subtype:  nimbus_cloud__nimbus__rain_cloud  a dark gray cloud bearing rain
        subtype:  storm_cloud__stormcloud  a heavy dark cloud presaging rain or a storm
        subtype:  stratus_cloud__stratuscloud__stratus__stratu  a large dark low cloud
           subtype:  altostratus_cloud__altostratuscloud__altostratus__altostratu  a stratus cloud at an intermediate altitude of 2 or 3 miles
     subtype:  air_pocket__airpocket  a local region of low pressure or descending air that causes a plane to lose height suddenly
     subtype:  aurora  an atmospheric phenomenon consisting of bands of light caused by charged solar particles following the earth's magnetic lines of force
        subtype:  aurora_australis__southern_lights  the aurora of the southern hemisphere
        subtype:  aurora_borealis__northern_lights  the aurora of the northern hemisphere
     subtype:  condensate__condensation  atmospheric moisture that has condensed because of cold
        subtype:  sweat  condensation of moisture on a cold surface; "the cold glasses were streaked with sweat"
        subtype:  dew  water that has condensed on a cool surface overnight from water vapor in the air; "in the morning the grass was wet with dew"
     subtype:  front.atmospheric_phenomenon  (meteorology) the atmospheric phenomenon created at the boundary between two different air masses
        subtype:  warm_front  the front of an advancing mass of warmer air
        subtype:  cold_front__polar_front__polarfront  the front of an advancing mass of colder air
           subtype:  squall_line  a cold front along which squalls or thunderstorms are likely
        subtype:  occluded_front__occlusion  (meteorology) a composite front when colder air surrounds a mass of warm air and forces it aloft
     subtype:  greenhouse_effect  warming that results when solar radiation is trapped by the atmosphere; caused by atmospheric gases that allow sunshine to pass through but absorb heat that is radiated back from the warmed surface of the earth
     subtype:  inversion  the layer of air near the earth is cooler than an overlying layer
     subtype:  violent_storm__violentstorm__storm  a violent weather condition with winds 64-72 knots (11 on the Beaufort scale) and precipitation and thunder and lightening
        subtype:  firestorm  a storm in which violent winds are drawn into the column of hot air rising over a severely bombed area
        subtype:  storm_center__stormcenter  the central area or point of lowest barometric pressure within a storm
        subtype:  northeaster__noreaster  a storm blowing from the northeast
        subtype:  hailstorm  a storm during which hail falls
        subtype:  ice_storm__icestorm__silver_storm  a storm with freezing rain that leaves everything glazed with ice
        subtype:  rainstorm  a storm with rain
           subtype:  line_storm__equinoctial_storm__equinoctialstorm  a violent rainstorm near the time of an equinox
           subtype:  thundershower  a short rainstorm accompanied by thunder and lightning
        subtype:  blizzard__snowstorm  a storm with widespread snowfall accompanied by strong winds
        subtype:  thunderstorm__electrical_storm__electric_storm  a storm resulting from strong rising air currents; heavy rain or hail along with thunder and lightning
        subtype:  windstorm  a storm consisting of violent winds
           subtype:  cyclone  a violent rotating windstorm
              subtype:  hurricane  a severe tropical cyclone usually with heavy rains and winds moving a 73-136 knots (12 on the Beaufort scale)
              subtype:  tornado__twister  a localized and violently destructive windstorm occurring over land characterized by a funnel-shaped cloud extending toward the ground
                 subtype:  waterspout.tornado  a tornado passing over water and picking up a column of water and mist
              subtype:  typhoon  a tropical cyclone occurring in the W Pacific or Indian oceans
           subtype:  dust_storm__sandstorm__sirocco  a windstorm that lifts up clouds of dust or sand
           subtype:  tempest  (literary) a violent wind; "a tempest swept over the island"
           subtype:  whirlwind  a more or less vertical column of air whirling around itself as it moves over the surface of the Earth
              subtype:  dust_devil  a miniature whirlwind strong enough to whip dust and leaves and litter into the air
     subtype:  atmospheric_electricity__atmosphericelectricity  electrical discharges in the atmosphere
        subtype:  elves__elve  an acronym for Emissions of Light and Very low frequency perturbations due to Electromagnetic pulse Sources; extremely bright extremely short (less than a msec) electrical flashes forming a huge ring (up to 400 km diameter) in the ionosphere
        subtype:  blue_jets__jets  atmospheric discharges (lasting 10 msec) bursting from the tops of giant storm clouds in blue cones that widen as they flash upward
        subtype:  lightning  abrupt electric discharge from cloud to cloud or from cloud to earth accompanied by the emission of light
           subtype:  forked_lightning__chain_lightning__chainlightning  a form of lightning that moves rapidly in a zigzag path with one end divided (fork-like)
           subtype:  bolt_of_lightning__thunderbolt__bolt  a discharge of lightning accompanied by thunder
        subtype:  red_sprites__redsprite__sprites__sprite  atmospheric electricity (lasting 10 msec) appearing as globular flashes of red (pink to blood-red) light rising to heights of 60 miles (sometimes seen together with elves)
     subtype:  midnight_sun  the sun visible at midnight (inside the arctic or antarctic circles)
     subtype:  halo  a circle of light around the sun or moon
        subtype:  solar_halo__solarhalo__parhelic_circle__parhelic_ring  a luminous halo parallel to the horizon at the altitude of the sun; caused by ice crystals in the atmosphere
     subtype:  meteor_shower__meteor_stream  a transient shower of meteors when a meteor swarm enters the earth's atmosphere
     subtype:  sunrise.atmospheric_phenomenon  atmospheric phenomena accompanying the daily appearance of the sun
     subtype:  sunset.atmospheric_phenomenon  atmospheric phenomena accompanying the daily disappearance of the sun
     subtype:  afterglow.atmospheric_phenomenon  a glow sometimes seen in the sky after sunset
     subtype:  weather_condition__weathercondition__weather__atmospheric_condition__atmosphericcondition  the meteorological conditions: temperature and wind and clouds and precipitation; "they were hoping for good weather"; "every day we have weather conditions and yesterday was no exception"
        subtype:  cold_weather__cold_snap__cold_wave__cold_spell  a period of unusually cold weather
           subtype:  frost__freeze  weather cold enough to cause freezing
        subtype:  fair_weather__sunshine__temperateness__temperatenes  moderate weather; suitable for outdoor activities
        subtype:  hot_weather__hotweather__heat_wave__hot_spell__hotspell  a period of unusually hot weather
           subtype:  scorcher  an extremely hot day
           subtype:  sultriness  oppressively hot and humid weather
        subtype:  thaw__thawing__warming  warm weather following a freeze; snow and ice melt; "they welcomed the spring thaw"
        subtype:  precipitation__downfall  the falling to earth of rain or snow or hail or sleet or mist
           subtype:  fine_spray  precipitation in very small drops
           subtype:  hail  precipitation of ice pellets when there are strong rising air currents
           subtype:  rainfall__rain  water falling in drops from vapor condensed in the atmosphere
              subtype:  monsoon.wind  any wind that changes direction with the seasons
              subtype:  rainstorm  a storm with rain
              subtype:  downpour__cloudburst__deluge__waterspout__torrent__soaker  a heavy rain
              subtype:  drizzle  very light rain; stronger than mist but less than a shower
              subtype:  rain_shower__shower  a brief period of precipitation; "the game was interrupted by a brief shower"
                 subtype:  scattering.rain_shower__sprinkle__sprinkling  a light shower that falls in some locations and not others nearby
           subtype:  sleet  partially melted snow (or a mixture of rain and snow)
           subtype:  snowfall__snow  precipitation falling from clouds in the form of ice crystals
              subtype:  snow_flurry__flurry  a light brief snowfall and gust of wind (or something resembling that); "he had to close the window against the flurries"; "there was a flurry of chicken feathers"
              subtype:  whiteout  an arctic atmospheric condition with clouds over snow produce a uniform whiteness and objects are difficult to see; occurs when the light reflected off the snow equals the light coming through the clouds
           subtype:  virga  light wispy precipitation that evaporates before it reaches the ground (especially when the lower air is low in humidity)
        subtype:  elements  violent or severe weather (viewed as caused by the action of the four elements); "they felt the full fury of the elements"
        subtype:  wind  air moving (sometimes with considerable force) from an area of high pressure to an area of low pressure; "trees bent under the fierce winds"; "when there is no wind, row"
           subtype:  airstream  a relatively well-defined prevailing wind
              subtype:  jet_stream__jetstream  a high-speed high-altitude airstream blowing from west to east near the top of the troposphere; has important effects of the formation of weather fronts
           subtype:  calm_air  wind moving at less than 1 knot; 0 on the Beaufort scale
           subtype:  zephyr__breeze__gentle_wind__air  a slight wind (usually refreshing); "the breeze was cooled by the lake"; "as he waited he could feel the air on his neck"
              subtype:  sea_breeze__seabreeze  a cooling breeze from the sea (during the daytime)
              subtype:  breath.zephyr  a slight movement of the air; "there wasn't a breath of air in the room"
              subtype:  light_air__lightair  wind moving 1-3 knots; 1 on the Beaufort scale
              subtype:  light_breeze__lightbreeze  wind moving 4-7 knots; 2 on the Beaufort scale
              subtype:  gentle_breeze  wind moving 8-12 knots; 3 on the Beaufort scale
              subtype:  moderate_breeze  wind moving 13-18 knots; 4 on the Beaufort scale
              subtype:  fresh_breeze__freshbreeze  wind moving 19-24 knots; 5 on the Beaufort scale
              subtype:  strong_breeze  wind moving 25-31 knots; 6 on the Beaufort scale
           subtype:  chinook_wind__chinookwind__chinook__snoweater  a warm dry wind blowing down the E slopes of the Rockies
           subtype:  harmattan  a dusty wind from the Sahara that blows toward the W coast of Africa during the winter
           subtype:  crosswind  wind blowing across the path or a ship or aircraft
           subtype:  fohn__foehn  a warm dry wind that blows down the northern slopes of the Alps
           subtype:  Santa_Ana.wind__santaana  a strong hot dry wind that blows in winter from the deserts of southern California toward the Pacific Coast
           subtype:  high_wind  a very strong wind; "rain and high winds covered the region"
           subtype:  headwind  wind blowing opposite to the path of a ship or aircraft
           subtype:  tailwind  wind blowing in the same direction as the path of a ship or aircraft
           subtype:  the_doldrums__doldrums  a belt of calms and light winds between the northern and southern trade winds of the Atlantic and Pacific
           subtype:  east_wind__easter__easterly  a wind from the east
              subtype:  levanter  an easterly wind in the western Mediterranean area
           subtype:  northwest_wind__northwestwind__northwester  a wind from the northwest
           subtype:  southwester__sou'wester  a strong wind from the southwest
           subtype:  southeaster__sou'easter  a strong wind from the southeast
           subtype:  gale  a strong wind moving 45-90 knots; force 7 to 10 on Beaufort scale
              subtype:  moderate_gale__near_gale  wind moving 32-38 knots; 7 on the Beaufort scale
              subtype:  fresh_gale__freshgale  wind moving 39-46 knots; 8 on the Beaufort scale
              subtype:  strong_gale  wind moving 47-54 knots; 9 on the Beaufort scale
              subtype:  whole_gale__wholegale  wind moving 55-63 knots; 10 on the Beaufort scale
           subtype:  gust__blast__blow  a strong current of air; "the tree was bent almost double by the gust"
              subtype:  bluster.gust  a violent gusty wind
              subtype:  sandblast  a blast of wind laden with sand
              subtype:  puff_of_air__puff__whiff  a short light gust of air
           subtype:  monsoon  a seasonal wind in S Asia; blows from the SW (bringing rain) in summer and from the NE in winter
           subtype:  monsoon.wind  any wind that changes direction with the seasons
           subtype:  north_wind__northwind__norther__boreas  a wind from the north
              subtype:  bise__bize  a dry cold north wind in SE France
              subtype:  mistral  a strong north wind that blows in France during the winter
              subtype:  tramontane__tramontana  a cold dry wind that blows south out of the mountains into Italy and the western Mediterranean
           subtype:  prevailing_wind  the predominant wind direction; "the prevailing wind is from the southwest"
              subtype:  antitrades  wind in the upper atmosphere blowing above but in the opposite direction from the trade winds
              subtype:  trade_wind__tradewind__trade  steady winds blowing from east to west above and below the equator; "they rode the trade winds going west"
              subtype:  antitrade_wind__antitradewind__antitrade  winds blowing from west to east and lying above the trade winds in the tropics
           subtype:  simoom__simoon__samiel  a violent hot sand-laden wind on the deserts of Arabia and North Africa
           subtype:  south_wind__southwind__souther__southerly  a wind from the south
           subtype:  squall  sudden violent winds; often accompanied by precipitation
              subtype:  line_squall  a squall advancing along a front that forms a definite line
           subtype:  air_current__aircurrent__draft__draught  a current of air (usually coming into a room or vehicle)
              subtype:  thermal  rising current of warm air
              subtype:  updraft  an strong upward air current
              subtype:  downdraft  a strong downward air current
           subtype:  west_wind__wester  wind that blows from west to east
              subtype:  prevailing_westerly__westerly  the west-to-east winds that occur in the temperate zones of the Earth
        subtype:  atmospheric_state__atmosphericstate__atmosphere  the weather or climate at some place; "the atmosphere was thick with fog"
           subtype:  air_mass  a large body of air with uniform characteristics horizontally
              subtype:  high_pressure__high  an air mass of higher than normal pressure; "the east coast benefits from a Bermuda high"
              subtype:  low_pressure__lowpressure__low__depression  an air mass of lower pressure; often brings precipitation; "a low moved in over night bringing sleet and snow"
           subtype:  anticyclone  (meteorology) winds spiraling outward from a high-pressure center; circling clockwise in the northern hemisphere and counter-clockwise in the southern
           subtype:  cyclone.atmospheric_state  (meteorology) rapid inward circulation of air masses about a low-pressure center; circling counterclockwise in the northern hemisphere and clockwise in the southern
           subtype:  fogginess__foggines__murk__murkiness  an atmosphere in which visibility is reduced because of a cloud of some substance
              subtype:  fug  (British informal) an airless smoky smelly atmosphere
        subtype:  good_weather  weather suitable for outdoor activities
           subtype:  calmness.good_weather  an absence of strong winds or rain
              subtype:  stillness__stillnes__windlessnes  calmness without winds
              subtype:  lull__quiet  a period of calm weather; "there was a lull in the storm"
           subtype:  mildness__clemency  good weather with comfortable temperatures
        subtype:  bad_weather__inclemency__inclementness__inclementnes  weather unsuitable for outdoor activities
           subtype:  raw_weather__rawweather  unpleasantly cold and damp weather
           subtype:  storminess  the state of being stormy; "he dreaded the storminess of the North Atlantic in winter"
              subtype:  boisterousness.storminess  a turbulent and stormy state of the sea
              subtype:  windiness__windines__breezines  a mildly windy state of the air
              subtype:  tempestuousness__tempestuousnes  a state of wild storminess
              subtype:  choppiness__roughness__roughnes__roughwater  used of the sea
           subtype:  cloud_cover__cloudcover__cloudiness__overcast  the state of the sky when it is covered by clouds
           subtype:  turbulence  instability in the atmosphere
              subtype:  clear-air_turbulence__clearairturbulence  strong turbulence in an otherwise cloudless region that subjects aircraft to violent updrafts or downdrafts
  subtype:  boundary_layer  the layer of slower flow of a fluid past a surface
  subtype:  chaos__chao  the formless and disordered state of matter before the creation of the cosmos
  subtype:  decalescence  phenomenon that occurs when a metal is being heated and there is a sudden slowing in the rate of temperature increase; slowing is caused by a change in the internal crystal structure of the metal
  subtype:  electrical_phenomenon  a physical phenomenon involving electricity
     subtype:  amperage  the strength of a electrical current measured in amperes
     subtype:  capacitance__electrical_capacity__capacity  an electrical phenomenon whereby an electric charge is stored
     subtype:  electrical_elastance__elastance  the reciprocal of capacitance
     subtype:  electric_charge__charge  the quantity of unbalanced electricity in a body (either positive or negative) and construed as an excess or deficiency of electrons; "the battery needed a fresh charge"
        subtype:  electrostatic_charge__electrostaticcharge  the electric charge at rest on the surface of an insulated body (which establishes and adjacent electrostatic field)
        subtype:  positive_charge  having a deficiency of electrons; having a higher electric potential
        subtype:  negative_charge  having a surplus of electrons; having a lower electric potential
     subtype:  pyroelectricity  generation of an electric charge on certain crystals (such as tourmaline) as a result of a change in temperature
     subtype:  electric_current__current  a flow of electricity through a conductor; "the current was measured in amperes"
        subtype:  thermionic_current  an electric current produced between two electrodes as a result of electrons emitted by thermionic emission
     subtype:  dielectric_heating  heating of an insulator by a high-frequency electric field
     subtype:  induction.electrical_phenomenon  an electrical phenomenon whereby an electromotive force (EMF) is generated in a closed circuit by a change in the flow of current
        subtype:  electromagnetic_mutual_induction__mutual_induction  generation of electromotive forces in each other by two adjacent circuits
        subtype:  self-induction  generation of an electromotive force (EMF) in a circuit by changing the current in that circuit; usually measured in henries
     subtype:  electric_potential__potential__potential_difference__potentialdifference__potential_drop__potentialdrop__voltage  the difference in electrical charge between two points in a circuit expressed in volts
        subtype:  evoked_potential  the electrical response of the central nervous system produced by an external stimulus; "he measured evoked potentials with an electroencephalogram"
        subtype:  resting_potential__restingpotential  the potential difference between the two sides of the membrane of a nerve cell when the cell is not conducting an impulse
     subtype:  conductance  a material's capacity to conduct electricity; measured as the reciprocal of electrical resistance
     subtype:  electric_resistance__electrical_resistance__impedance__resistance__resistivity__ohmic_resistance__ohmicresistance  a material's opposition to the flow of electric current; measured in ohms
        subtype:  ohmage  the ohmic resistance of a conductor
     subtype:  reactance  opposition to the flow of electric current resulting from inductance and capacitance (rather than resistance)
     subtype:  reluctance  (physics) opposition to magnetic flux (analogous to electric resistance)
     subtype:  skin_effect  the tendency of high-frequency alternating current to distribute near the surface of a conductor
     subtype:  electrical_disturbance  electrical signals produced by unwanted sources (atmospherics or receiver noise or unwanted transmitters)
     subtype:  voltage__electromotiveforce__emf  the rate at which energy is drawn from a source that produces a flow of electricity in a circuit; expressed in volts
  subtype:  electricity  a physical phenomenon associated with stationary or moving electrons and protons
     subtype:  galvanism  electricity produced by chemical action
     subtype:  hydroelectricity  electricity produced by water power
     subtype:  piezoelectricity__piezoelectric_effect__piezoelectriceffect__piezo_effect__piezoeffect  electricity produced by mechanical pressure on certain crystals (notably quartz or Rochelle salt); alternatively, electrostatic stress produces a change in the linear dimensions of the crystal
     subtype:  static_electricity  electricity produced by friction
     subtype:  dynamic_electricity__dynamicelectricity__current_electricity__currentelectricity  a flow of electric charge
     subtype:  thermoelectricity  electricity produced by heat (as in a thermocouple)
  subtype:  energy  (physics) 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"
     subtype:  activation_energy  the energy that an atomic system must acquire before a process (such as an emission or reaction) can occur
     subtype:  alternative_energy__alternativeenergy  energy derived from sources that do not use up natural resources or harm the environment
        subtype:  solar_energy__solarenergy__solar_power__solarpower  energy from the sun that is converted into thermal or electrical energy; "the amount of energy falling on the earth is given by the solar constant, but very little use has been made of solar energy"
        subtype:  wind_generation__wind_power  power derived from the wind (as by windmills)
     subtype:  atomic_energy__nuclear_energy__nuclearenergy  the energy released by a nuclear reaction
        subtype:  atomic_power__nuclear_power__nuclearpower  nuclear energy regarded as a source of electricity for the power grid (for civilian use)
     subtype:  binding_energy__bindingenergy__separation_energy  the energy required to separate particles from a molecule or atom or nucleus; equals the mass defect
     subtype:  chemical_energy__chemicalenergy  that part of the energy in a substance that can be released by a chemical reaction
     subtype:  electrical_energy__electricity  energy made available by the flow of electric charge through a conductor; "they built a car that runs on electricity"
        subtype:  alternating_current__alternatingcurrent__AC  an electric current that reverses direction sinusoidally; "In the US most household current is AC at 60 cycles per second"
        subtype:  direct_current__DC  an electric current that flows in one direction steadily
        subtype:  signal.electrical_energy  an electric quantity (voltage or current or field strength) whose modulation represents coded information about the source from which it comes
     subtype:  energy_level__energy_state  a definite stable energy that a physical system can have; used especially of the state of electrons in atoms or molecules; "according to quantum theory only certain energy levels are possible"
     subtype:  rest_energy  the energy equivalent to the mass of a particle at rest in an inertial frame of reference; equal to the rest mass times the square of the speed of light
     subtype:  work.energy  (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"
     subtype:  heat_energy__heat  a form of energy that is transferred by a difference in temperature
        subtype:  heat_of_dissociation  the heat required for a fluid substance to break up into simpler constituents
        subtype:  heat_of_formation  the heat evolved or absorbed during the formation of one mole of a substance from its component elements
        subtype:  heat_of_solution  the heat evolved or absorbed when one mole of a substance is dissolved in a large volume of a solvent
        subtype:  latent_heat__heat_of_transformation  heat absorbed or radiated during a change of phase at a constant temperature and pressure
           subtype:  heat_of_condensation  heat liberated by a unit mass of gas at its boiling point as it condenses into a liquid; "the heat of condensation is equal to the heat of vaporization"
           subtype:  heat_of_fusion  heat absorbed by a unit mass of a solid at its melting point in order to convert the solid into a liquid at the same temperature; "the heat of fusion is equal to the heat of solidification"
           subtype:  heat_of_solidification  heat liberated by a unit mass of liquid at its freezing point when it solidifies
           subtype:  heat_of_sublimation  heat absorbed by a unit mass of material when it changes from a solid to a gaseous state
           subtype:  heat_of_vaporization__heat_of_vaporisation  heat absorbed by a unit mass of a material at its boiling point in order to convert the material into a gas at the same temperature
        subtype:  specific_heat  the heat required to raise the temperature of one gram of a substance one degree centigrade
     subtype:  mechanical_energy  energy in a mechanical form
        subtype:  kinetic_energy__kineticenergy__K.E.  the mechanical energy that a body has by virtue of its motion
        subtype:  potential_energy__potentialenergy__P.E.  the mechanical energy that a body has by virtue of its position; stored energy
           subtype:  elastic_energy__elasticenergy__elastic_potential_energy__elasticpotentialenergy  potential energy that is stored when a body is deformed (as in a coiled spring)
     subtype:  radiant_energy__radiantenergy  energy that is transmitted in the form of (electromagnetic) radiation; energy that exists in the absence of matter
        subtype:  luminous_energy  the energy associated with visible light
  subtype:  power  (physics) the rate of doing work; measured in watts (= joules/second)
     subtype:  electrical_power__electric_power__wattage  the product of voltage and current
        subtype:  load.electrical_power  the power output of a generator or power plant
     subtype:  waterpower  the power to do work that is latent in a head of water
  subtype:  ectropy  the opposite of entropy: increasing order (as resulting from growth and development)
  subtype:  entropy  (thermodynamics) a measure of the amount of energy in a system that is available for doing work; entropy increases as matter and energy in the universe degrade to an ultimate state of inert uniformity
     subtype:  conformational_entropy  entropy calculated from the probability that a state could be reached by chance alone
  subtype:  event.physical_phenomenon  (relativity theory) a phenomenon located at a single point in space-time; the fundamental observational entity in relativity theory
  subtype:  field_of_force__field__force_field__forcefield  the space around a radiating body within which its electromagnetic oscillations can exert force on another similar body not in contact with it
     subtype:  electric_field  a field of force surrounding a charged particle
        subtype:  electrostatic_field__electrostaticfield  electric field associated with static electric charges
     subtype:  gravitational_field__gravitationalfield  a field of force surrounding a body of finite mass
     subtype:  magnetic_field__magnetic_flux__flux  the lines of force surrounding a permanent magnet or a moving charged particle
        subtype:  magnetosphere  the magnetic field of a planet; the volume around the planet in which charged particles are subject more to the planet's magnetic field than to the solar magnetic field
        subtype:  solar_magnetic_field  the magnetic field of the sun
     subtype:  radiation_field__radiationfield  a field that represents the energy lost from the radiator to space
  subtype:  force  the physical influence that produces a change in a physical quantity; "force equals mass times acceleration"
     subtype:  aerodynamic_force__aerodynamicforce  forces acting on airfoils in motion relative to the air (or other gaseous fluids)
        subtype:  aerodynamic_lift__aerodynamiclift__lift  the component of the aerodynamic forces acting on an airfoil that opposes gravity
           subtype:  ground_effect  apparent increase in aerodynamic lift experienced by an aircraft flying close to the ground
     subtype:  chemical_attraction__affinity  the force attracting atoms to each other and binding them together in a molecule: "basic dyes have an affinity for wool and silk"
     subtype:  attractive_force__attraction  the force by which one object attracts another
        subtype:  affinity  (immunology) the attraction between an antigen and an antibody
        subtype:  chemical_bond__bond  an electrical force linking atoms
           subtype:  covalent_bond  a chemical bond that involves sharing a pair of electrons between atoms in a molecule
              subtype:  coordinate_bond__dative_bond  a covalent bond in which both electrons are provided by one of the atoms
           subtype:  cross-link__crosslink__crosslinkage  a side bond that links two adjacent chains of atoms in a complex molecule
           subtype:  hydrogen_bond  a chemical bond consisting of a hydrogen atom between two electronegative atoms (e.g., oxygen or nitrogen) with one side be a covalent bond and the other being an ionic bond
           subtype:  ionic_bond__ionicbond__electrovalent_bond__electrovalentbond__electrostatic_bond__electrostaticbond  a chemical bond in which one atom loses an electron to form a positive ion and the other atom gains to electron to form a negative ion
           subtype:  metallic_bond  a chemical bond in which electrons are shared over many nuclei and electronic conduction occurs
           subtype:  peptide_bond__peptidebond__peptide_linkage__peptidelinkage  the primary linkage of all protein structures; the chemical bond between the carboxyl groups and amino groups that unites a peptide
        subtype:  gravity__gravitation__gravitational_attraction__gravitationalattraction__gravitational_force__gravitationalforce  the force of attraction between all masses in the universe; especially the attraction of the earth's mass for bodies near its surface; "gravitation cannot be held responsible for people falling in love"--Albert Einstein
           subtype:  solar_gravity__solargravity  the gravity of the sun; "solar gravity creates extreme pressures and temperatures"
        subtype:  magnetism__magnetic_attraction__magnetic_force  attraction for iron; associated with electric currents as well as magnets; characterized by fields of force
           subtype:  electromagnetism  magnetism produced by an electric current; "electromagnetism was discovered when it was observed that a copper wire carrying an electric current can magnetize pieces of iron or steel near it"
           subtype:  antiferromagnetism  magnetic field creates parallel but opposing spins; varies with temperature
              subtype:  ferrimagnetism  a phenomenon in ferrites where there can be incomplete cancellation of antiferromagnetic arranged spins giving a net magnetic moment
           subtype:  diamagnetism  phenomenon exhibited by materials like copper or bismuth that become magnetized in a magnetic field with a polarity opposite to the magnetic force; unlike iron they are slightly repelled by a magnet
           subtype:  ferromagnetism  phenomenon exhibited by materials like iron (nickel or cobalt) that become magnetized in a magnetic field and retain their magnetism when the field is removed
           subtype:  paramagnetism  materials like aluminum or platinum become magnetized in a magnetic field but it disappears when the field is removed
        subtype:  van_der_Waal's_forces  relatively weak attraction between neutral atoms and molecules arising from polarization induced in each particle by the presence of other particles
     subtype:  repulsive_force__repulsiveforce__repulsion  the force by which bodies repel one another
     subtype:  centrifugal_force__centrifugalforce  the outward force on a body moving in a curved path around another body
     subtype:  centripetal_force__centripetalforce  the inward force on a body moving in a curved path around another body
     subtype:  cohesion  (physics) the intermolecular force that holds together the molecules in a solid or liquid
     subtype:  Coriolis_force  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
     subtype:  impetus__impetu__drift__impulsion  a force that moves something along
     subtype:  Lorentz_force  the force experienced by a point charge moving along a wire that is in a magnetic field; the force is at right angles to both the current and the magnetic field; "the Lorentz force can be used to suspend a current-carrying object between two magnets"
     subtype:  moment.force  the moment of a couple is the product of its force and the distance between its opposing forces
        subtype:  dipole_moment  the moment of a dipole
           subtype:  electric_dipole_moment  the dipole moment in an electric dipole
           subtype:  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"
     subtype:  propulsion  a propelling force
        subtype:  nuclear_propulsion__nuclearpropulsion  the use of a nuclear reactor either to produce electricity to power an engine (as in a nuclear submarine) or to directly heat a propellant (as in nuclear rockets)
        subtype:  reaction_propulsion  propulsion that results from the ejection at high velocity of a mass of gas to which the vehicle reacts with an equal and opposite momentum
           subtype:  jet_propulsion__jetpropulsion  propulsion by means of the discharge of a jet of fluid toward the rear
           subtype:  rocket_propulsion  reaction propulsion using stored oxygen for combustion; used where there is insufficient atmospheric oxygen
     subtype:  pull.force  the force used in pulling; "the pull of the moon"; "the pull of the current"
     subtype:  push.force__thrust  the force used in pushing; "the push of the water on the walls of the tank"; "the thrust of the jet engines"
     subtype:  reaction.force  (mechanics) the equal and opposite force that is produced when any force is applied to a body; "every action has an equal and opposite reaction"
     subtype:  stress  (physics) force that produces strain on a physical body
        subtype:  tension.stress  (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"
        subtype:  breaking_point  the degree of tension or stress at which something breaks
     subtype:  torsion__torque  a twisting force
        subtype:  magnetic_moment__moment_of_a_magnet  the torque exerted on a magnet or dipole when it is placed in a magnetic field
     subtype:  magnetomotive_force  the force that produces magnetic flux
     subtype:  life_force__vital_force__vitalforce__vitality__elan_vital  (biology) a hypothetical force (not physical or chemical) once thought by Henri Bergson to cause the evolution and development of organisms
  subtype:  hysteresis  the lagging of an effect behind its cause; especially the phenomenon in which the magnetic induction of a ferromagnetic material lags behind the changing magnetic field
  subtype:  resonance  an excited state of a stable particle causing a sharp maximum in the probability of absorption of electromagnetic radiation
     subtype:  nuclear_resonance__nuclearresonance  the resonance absorption of a gamma ray by a nucleus identical to the nucleus that emitted the gamma ray
     subtype:  magnetic_resonance  resonance of electrons or atoms or molecules or nuclei to radiation frequencies as a result of space quantization in a magnetic field
        subtype:  nuclear_magnetic_resonance__NMR__proton_magnetic_resonance  resonance of protons to radiation in a magnetic field
  subtype:  mechanical_phenomenon  a physical phenomenon associated with the equilibrium or motion of objects
     subtype:  inertia  (physics) the tendency of a body to maintain is state of rest or uniform motion unless acted upon by an external force
        subtype:  moment_of_inertia  the tendency of a body to resist angular acceleration
     subtype:  leverage.mechanical_phenomenon__purchase  the mechanical advantage gained by being in a position to use a lever
     subtype:  sound.mechanical_phenomenon  mechanical vibrations transmitted by an elastic medium; "falling trees make a sound in the forest even when no one is there to hear them"
        subtype:  ultrasound  very high frequency sound; used in ultrasonography
        subtype:  sound_unit__soundunit  any acoustic unit of measurement
           subtype:  bel__B  a logarithmic unit of sound intensity equal to 10 decibels
           subtype:  decibel__dB__db__db  a logarithmic unit of sound intensity; 10 times the logarithm of the ratio of the sound intensity to some reference intensity
           subtype:  sone  a unit of perceived loudness equal to the loudness of a 1000-hertz tone at 40 dB above threshold
           subtype:  phon  a unit of subjective loudness
     subtype:  trajectory__flight  the path followed by an object moving through space
        subtype:  ballistic_trajectory__ballistictrajectory__ballistics  the trajectory of an object in free flight
        subtype:  gravity-assist__gravityassist  (spaceflight) a trajectory that passes close to a planetary body in order to gain energy from its gravitational field
     subtype:  resistance.mechanical_phenomenon  any mechanical force that tends to retard or oppose motion
        subtype:  friction__rubbing  the resistance encountered when one body is moved in contact with another
           subtype:  abrasion__grinding__attrition__detrition  the wearing down of rock particles by friction due to water or wind or ice
           subtype:  adhesive_friction__grip__traction  the friction between a body and the surface on which it moves (as between an automobile tire and the road)
        subtype:  acoustic_resistance__acoustic_impedance__acoustic_reactance  opposition to the flow of sound through a surface; acoustic resistance is the real component of acoustic impedance and acoustic reactance is the imaginary component
        subtype:  retarding_force__retardingforce__drag  the phenomenon of resistance to motion through a fluid
           subtype:  sonic_barrier__sonicbarrier__sound_barrier__soundbarrier  the increase in aerodynamic drag as an airplane approaches the speed of sound
           subtype:  windage.retarding_force  the retarding force of air friction on a moving object
  subtype:  opacity  the phenomenon of not permitting the passage of electromagnetic radiation
     subtype:  optical_opacity__opticalopacity  opacity to light
     subtype:  radiopacity__radio-opacity__radioopacity  opacity to X-rays or other radiation
  subtype:  optical_phenomenon__opticalphenomenon  a physical phenomenon related to or involving light
     subtype:  optical_aberration__opticalaberration__aberration__distortion  an optical phenomenon resulting from the failure of a lens or mirror to produce a good image
        subtype:  chromatic_aberration__chromaticaberration  an optical aberration in which the image has colored fringes
        subtype:  spherical_aberration__sphericalaberration  a optical aberration resulting in a distorted image
     subtype:  absorption_band  a dark band in the spectrum of white light that has been transmitted through a substance that exhibits absorption at selective wavelengths
     subtype:  diffraction  when light passes sharp edges or goes through narrow slits the rays are deflected and produce fringes of light and dark bands
        subtype:  X-ray_diffraction  the scattering of X rays by the atoms of a crystal; the diffraction pattern shows structure of the crystal
     subtype:  incidence  the striking of a light beam on a surface; "he measured the angle of incidence of the reflected light"
     subtype:  optical_illusion__opticalillusion  an optical phenomenon that results in a false or deceptive visual impression
        subtype:  apparent_motion__motion__apparent_movement__movement  an optical illusion of motion produced by viewing a rapid succession of still pictures of a moving object; "the cinema relies on apparent motion"; "the succession of flashing lights gave an illusion of movement"
        subtype:  mirage.optical_illusion  an optical illusion in which atmospheric refraction by a layer of hot air distorts or inverts reflections of distant objects
           subtype:  fata_morgana  a mirage in the Strait of Messina (attributed to the Arthurian sorcerer Morgan le Fay)
     subtype:  pleochroism  the phenomenon of different colors appearing when certain crystals are viewed from different directions
        subtype:  dichroism  pleochroism of a crystal so that it exhibits two different colors when viewed from two different directions
        subtype:  trichroism  pleochroism of a crystal so that it exhibits three different colors when viewed from three different directions
     subtype:  polarization__polarisation  the phenomenon in which waves of light or other radiation are restricted in direction of vibration
     subtype:  parallax  the apparent displacement of an object as seen from two different points that are not on a line with the object
        subtype:  heliocentric_parallax__annual_parallax  the parallax of a celestial body using two points in the earth's orbit around the sun as the baseline
           subtype:  stellar_parallax__stellarparallax  the heliocentric parallax of a star
        subtype:  geocentric_parallax__diurnal_parallax__diurnalparallax  the parallax of a celestial body using two points on the surface of the earth as the earth rotates
           subtype:  horizontal_parallax  the maximum parallax observed when the celestial body is at the horizon
           subtype:  solar_parallax__solarparallax  the angle subtended by the mean equatorial radius of the Earth at a distance of one astronomical unit
     subtype:  Tyndall_effect  the phenomenon in which light is scattered by very small particles in its path; it makes a beam of light visible; the scattered light is mainly blue
  subtype:  pressure_level__pressure__force_per_unit_area  the force applied to a unit area of surface; measured in pascals (SI unit) or in dynes (cgs unit); "the compressed gas exerts an increased pressure"
     subtype:  blood_pressure__bloodpressure  the pressure of the circulating blood against the walls of the blood vessels; results from the systole of the left ventricle of the heart; sometimes measured for a quick evaluation of a person's health; "adult blood pressure is considered normal at 120/80 where the first number is the systolic pressure and the second is the diastolic pressure"
        subtype:  systolic_pressure  the blood pressure (as measured by a sphygmomanometer) during the contraction of the left ventricle of the heart
        subtype:  diastolic_pressure__diastolicpressure  the blood pressure (as measured by a sphygmomanometer) after the contraction of the heart while the chambers of the heart refill with blood
        subtype:  arterial_pressure  the pressure of the circulating blood on the arteries; "arterial pressure is the product of cardiac output and vascular resistance"
        subtype:  venous_pressure  the pressure exerted on the walls of the veins by the circulating blood
     subtype:  gas_pressure__gaspressure  the pressure exerted by a gas
        subtype:  atmospheric_pressure__atmosphericpressure__air_pressure__airpressure  the pressure exerted by the atmosphere
           subtype:  compartment_pressure__compartmentpressure  the air pressure maintained in the air-tight compartment of an aircraft
           subtype:  barometric_pressure  atmospheric pressure as indicated by a barometer
     subtype:  head.pressure_level  the pressure exerted by a fluid; "a head of steam"
     subtype:  hydrostatic_head__hydrostatichead  the pressure at a given point in a liquid measured in terms of the vertical height of a column of the liquid needed to produce the same pressure
     subtype:  intraocular_pressure__intraocularpressure  pressure inside the eyeball;regulated by resistance to the outward flow of aqueous humor; "glaucoma results from increased intraocular pressure"
     subtype:  oil_pressure__oilpressure  pressure that keeps oil on the moving parts of an internal-combustion engine
     subtype:  osmotic_pressure__osmoticpressure  (physical chemistry) the pressure exerted by a solution necessary to prevent osmosis into that solution when it is separated from the pure solvent by a semipermeable membrane
     subtype:  corpuscular-radiation_pressure__corpuscularradiationpressure__radiation_pressure__radiationpressure  the minute pressure exerted on a surface normal to the direction of propagation of a wave
        subtype:  acoustic_radiation_pressure  (acoustics) the pressure exerted on a surface normal to the direction of propagation of a sound wave
     subtype:  instantaneous_sound_pressure__instantaneoussoundpressure__sound_pressure__soundpressure  the difference between the instantaneous pressure at a point in a sound field and the average pressure at that point
     subtype:  suction  a force over an area produced by a pressure difference
     subtype:  vapor_pressure__vaporpressure__vapour_pressure  the pressure exerted by a vapor; often understood to mean saturated vapor pressure (the vapor pressure of a vapor in contact with its liquid form)
  subtype:  radiation  the physical phenomenon of radiating energy in the form of waves or particles
     subtype:  ionizing_radiation  high-energy radiation capable of producing ionization in substances through which it passes
        subtype:  alpha_radiation__alpha_ray__alpharay  the radiation of alpha particles during radioactive decay
        subtype:  beta_radiation__beta_ray__electron_radiation  radiation of beta particles during radioactive decay
        subtype:  cosmic_ray  highly penetrating ionizing radiation of extraterrestrial origin; consisting chiefly of protons and alpha particles; collision with atmospheric particles results in rays and particles of many kinds
        subtype:  neutron_radiation__neutronradiation  radiation of neutrons (as by a neutron bomb)
        subtype:  X_ray__X-radiation__roentgen_ray  electromagnetic radiation of short wavelength produced when high-speed electrons strike a solid target
     subtype:  electromagnetic_radiation__electromagneticradiation__electromagnetic_wave__electromagneticwave__nonparticulate_radiation  radiation consisting of waves of energy associated with electric and magnetic fields resulting from the acceleration of an electric charge
        subtype:  actinic_radiation__actinic_ray__actinicray  electromagnetic radiation that can produce photochemical reactions
           subtype:  infrared_radiation__infrared__infrared_light__infrared_emission  electromagnetic radiation with wavelengths longer than visible light but shorter than radio waves
           subtype:  visible_light__visiblelight__light__visible_radiation__visibleradiation  (physics) electromagnetic radiation that can produce a visual sensation; "the light was filtered through a soft glass window"
              subtype:  beam_of_light__beam__light_beam__lightbeam__ray__rayoflight__shaft__shaft_of_light  a column of light (as from a beacon)
                 subtype:  heat_ray  a ray that produces a thermal effect
                    subtype:  infrared_ray  a ray of infrared radiation; produces a thermal effect (as from an infrared lamp)
                 subtype:  high_beam  the beam of a car's headlights that provides distant illumination
                 subtype:  moonbeam__moonray  a ray of moonlight
                 subtype:  sunbeam__sunray  a ray of sunlight
                 subtype:  laser_beam__laserbeam  a beam of light generated by a laser
                 subtype:  low_beam__lowbeam  the beam of a car's headlights that provides illumination for a short distance
              subtype:  candlelight__candle_flame  the light provided by a burning candle
              subtype:  corona.visible_light  one or more circles of light seen around a luminous object
              subtype:  counterglow__gegenschein  a faint spot of light in the night sky that appears directly opposite the position of the sun; a reflection of sunlight by micrometeoric material in space
              subtype:  daylight  light during the daytime
              subtype:  firelight  the light of a fire (especially in a fireplace)
              subtype:  fluorescence  light emitted during absorption of radiation of some other (invisible) wavelength
                 subtype:  autofluorescence  self-induced fluorescence
                 subtype:  phosphorescence  a fluorescence that persists after the bombarding radiation has ceased
              subtype:  friar's_lantern__ignis_fatuus__jack-o'-lantern__will-o'-the-wisp  a pale light sometimes seen at night over marshy ground
              subtype:  gaslight  light yielded by the combustion of illuminating gas
              subtype:  glowing__radiance__glow  the amount of electromagnetic radiation leaving or arriving at a point on a surface
                 subtype:  aureole__corona  the outermost region of the sun's atmosphere; visible as a white halo during a solar eclipse
              subtype:  half-light  a grayish light (as at dawn or dusk or in dim interiors)
              subtype:  incandescence.visible_light__glow  the phenomenon of light emission by a body as its temperature is raised
              subtype:  lamplight  light from a lamp
              subtype:  luminescence  light not due to incandescence; occurs at low temperatures
                 subtype:  bioluminescence  luminescence produced by physiological processes (as in the firefly)
                 subtype:  chemiluminescence  luminescence resulting from a chemical reaction as the oxidation of luciferin in fireflies
              subtype:  meteor__shooting_star  a streak of light in the sky at night that results when a meteoroid hits the earth's atmosphere and air friction causes the meteoroid to melt or vaporize or explode
                 subtype:  bolide__fireball  an especially luminous meteor (sometimes exploding)
              subtype:  moonlight__moonshine__moon  the light of the moon; "moonlight is the smuggler's enemy"; "the moon was bright enough to read by"
              subtype:  starlight  the light of the stars
              subtype:  sunlight__sunshine__sun  the rays of the sun; "the shingles were weathered by the sun and wind"
              subtype:  streamer  light that streams; "streamers of flames"
              subtype:  torchlight  light from a torch or torches
              subtype:  twilight  the diffused light from the sky when the sun is below the horizon but its rays are refracted by the atmosphere of the earth
           subtype:  ultraviolet_illumination__ultravioletillumination__ultraviolet__ultraviolet_radiation__ultravioletradiation__ultraviolet_light__ultravioletlight__UV  radiation lying in the ultraviolet range; wave lengths shorter than light but longer than X rays
        subtype:  electron_beam__beam__ray  a group of nearly parallel lines of electromagnetic radiation
           subtype:  cathode_ray__cathoderay  a beam of electrons emitted by the cathode of an electrical discharge tube
           subtype:  particle_beam  a collimated flow of particles (atoms or electrons or molecules)
              subtype:  ion_beam__ionbeam__inoic_beam__inoicbeam  a beam of ions moving in the same direction at the same speed
        subtype:  black-body_radiation__blackbody_radiation__blackbodyradiation  the electromagnetic radiation that would be radiated from an ideal black body; the distribution of energy in the radiated spectrum of a black body depends only on temperature and is determined by Planck's radiation law
        subtype:  Hertzian_wave  an electromagnetic wave generated by oscillations in an electric circuit
        subtype:  gamma_radiation__gammaradiation__gamma_ray__gammaray  electromagnetic radiation emitted during radioactive decay and having an extremely short wavelength
        subtype:  line.electromagnetic_radiation  a single frequency (or very narrow band) of radiation in a spectrum
        subtype:  microwave  a short electromagnetic wave (longer than infrared but shorter than radio waves); used for radar and microwave ovens
        subtype:  radio_wave__radiowave__radio_emission__radioemission__radio_radiation__radioradiation  an electromagnetic wave with a wavelength between 0.5 cm to 30,000 m
           subtype:  sky_wave__skywave  a radio wave that is reflected back to earth by the ionosphere or a communications satellite; permits transmission around the curve of the earth's surface
              subtype:  ionospheric_wave__ionosphericwave  a sky wave that is reflected by the ionosphere
           subtype:  ground_wave  a radio wave propagated on or near the earth's surface
           subtype:  radio_signal__radiosignal  a radio wave used to transmit and receive messages
           subtype:  carrier_wave__carrierwave__carrier  a radio wave that can be modulated in order to transmit a signal
           subtype:  short_wave__shortwave  a radio wave with a wavelength less than 100 meters
           subtype:  long_wave  a radio wave with a frequency less than 300 kilohertz
        subtype:  X_ray__X-radiation__roentgen_ray  electromagnetic radiation of short wavelength produced when high-speed electrons strike a solid target
     subtype:  corpuscular_radiation__corpuscularradiation__particulate_radiation__particulateradiation  a stream of atomic or subatomic particles that may be charged positively (e.g. alpha particles) or negatively (e.g. beta particles) or not at all (e.g. neutrons)
        subtype:  alpha_radiation__alpha_ray__alpharay  the radiation of alpha particles during radioactive decay
        subtype:  beta_radiation__beta_ray__electron_radiation  radiation of beta particles during radioactive decay
        subtype:  neutron_radiation__neutronradiation  radiation of neutrons (as by a neutron bomb)
     subtype:  radioactivity__activity  radiation resulting from radioactive decay
     subtype:  solar_radiation__solarradiation  radiation from the sun
        subtype:  solar_flare__solarflare__flare  a sudden eruption of intense high-energy radiation from the sun's surface; associated with sunspots and radio interference
        subtype:  solar_prominence__solarprominence  large eruptions of luminous hydrogen gas that rise thousands of kilometers above the chromosphere
        subtype:  solar_wind__solarwind  a stream of protons moving radially from the sun
     subtype:  radiation.action  the act of radiating
        subtype:  bombardment  the act (or an instance) of subjecting a body or substance to the impact of high-energy particles (as electrons or alpha rays)
  subtype:  reflection.physical_phenomenon__reflexion  the phenomenon of a propagating wave (light or sound) being thrown back from a surface
     subtype:  virtual_image__virtualimage  a reflected optical image (as seen in a plane mirror)
     subtype:  zodiacal_light  a luminous tract in the sky; a reflection of sunlight from cosmic dust in the plane of the ecliptic; visible just before sunrise and just after sunset
  subtype:  refraction  the change in direction of a propagating wave (light or sound) when passing from one medium to another
     subtype:  double_refraction__birefringence  splitting a ray into two parallel rays polarized perpendicularly
  subtype:  resolving_power__resolvingpower__resolution  the ability of a microscope or telescope to measure the angular separation of images that are close together
  subtype:  resolution.physical_phenomenon  (computer science) the number of pixels per square inch on a computer-generated display; the greater the resolution, the better the picture
  subtype:  conduction__conductivity  the transmission of heat or electricity or sound
     subtype:  electrical_conduction  the passage of electricity through a conductor
        subtype:  photoconductivity__photoconduction  change in the electrical conductivity of a substance as a result of absorbing electromagnetic radiation
        subtype:  superconductivity  the disappearance of electrical resistance at very low temperatures
        subtype:  electric_discharge__discharge__spark__arc__electric_arc  electrical conduction through a gas in an applied electric field
           subtype:  brush_discharge  discharge between electrodes creating visible streamers of ionized particles
           subtype:  corona_discharge__corona__corposant__st.elmo'sfire__Saint_Elmo's_fire__Saint_Elmo's_light__Saint_Ulmo's_fire__Saint_Ulmo's_light__electric_glow  an electrical discharge accompanied by ionization of surrounding atmosphere
  subtype:  propagation  the movement of a wave through a medium
     subtype:  Doppler_effect__Doppler_shift  change in the apparent frequency of a wave as observer and source move toward or away from each other
        subtype:  red_shift__redshift  (astronomy) a shift in the spectra of distant galaxies toward longer wavelengths; generally interpreted as the Doppler effect resulting from the velocity at which they recede as the universe expands
     subtype:  wave_front  all the points just reached by a wave as it propagates
  subtype:  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
     subtype:  electromagnetic_interaction__electromagneticinteraction  an interaction between charged elementary particles that is intermediate in strength between the strong and weak interactions; mediated by photons
     subtype:  gravitational_interaction__gravitationalinteraction  a weak interaction between particles that results from their mass; mediated by gravitons
     subtype:  strong_interaction__strong_force__color_force__colorforce  (physics) the interaction that binds protons and neutrons together in the nuclei of atoms; mediated by gluons
     subtype:  weak_interaction__weak_force  (physics) an interaction between elementary particles involving neutrinos or antineutrinos that is responsible for certain kinds of radioactive decay; mediated by intermediate vector bosons
  subtype:  surface_tension__surfacetension  a phenomenon at the surface of a liquid caused by intermolecular forces
     subtype:  capillarity__capillary_action__capillaryaction  a phenomenon associated with surface tension and resulting in the elevation or depression of liquids in capillaries
     subtype:  interfacial_tension__interfacialtension__interfacial_surface_tension__interfacialsurfacetension  surface tension at the surface separating two non-miscible liquids
  subtype:  syzygy  the straight line configuration of 3 celestial bodies (as the sun and earth and moon) in a gravitational system
  subtype:  transparence__transparency  permitting the free passage of electromagnetic radiation
  subtype:  turbulency__turbulence  unstable flow of a liquid or gas
     subtype:  tide_rip__rip__riptide__crosscurrent  a stretch of turbulent water in the sea
  subtype:  floatation__flotation  the phenomenon of floating (remaining on the surface of a liquid)

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