Nouns denoting natural phenomena
- aberration
- an optical phenomenon resulting from the failure of a lens or mirror to produce a good image
- abiogenesis
- a hypothetical organic phenomenon by which living organisms are created from nonliving matter
- abrasion
- the wearing down of rock particles by friction due to water or wind or ice
- absorption band
- a dark band in the spectrum of white light that has been transmitted through a substance that exhibits absorption at selective wavelengths
- absorption spectrum
- the spectrum of electromagnetic radiation that has passed through a medium that absorbed radiation of certain wavelengths
- AC
- an electric current that reverses direction sinusoidally
- acoustic impedance
- 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
- acoustic phenomenon
- a physical phenomenon associated with the production or transmission of sound
- acoustic projection
- the acoustic phenomenon that gives sound a penetrating quality
- acoustic spectrum
- the distribution of energy as a function of frequency for a particular sound source
- actinic radiation
- electromagnetic radiation that can produce photochemical reactions
- action spectrum
- the efficiency with which electromagnetic radiation produces a photochemical reaction plotted as a function of the wavelength of the radiation
- activation energy
- the energy that an atomic system must acquire before a process (such as an emission or reaction) can occur
- adhesive friction
- the friction between a body and the surface on which it moves (as between an automobile tire and the road)
- aerobiosis
- life sustained in the presence of air or oxygen
- aerodynamic force
- forces acting on airfoils in motion relative to the air (or other gaseous fluids)
- aerodynamic lift
- the component of the aerodynamic forces acting on an airfoil that opposes gravity
- aerosol
- a cloud of solid or liquid particles in a gas
- affinity
- (immunology) the attraction between an antigen and an antibody
- affinity
- the force attracting atoms to each other and binding them together in a molecule
- aftereffect
- any result that follows its cause after an interval
- afterglow
- a glow sometimes seen in the sky after sunset
- aftermath
- the consequences of an event (especially a catastrophic event)
- air current
- air moving (sometimes with considerable force) from an area of high pressure to an area of low pressure
- air hole
- a local region of low pressure or descending air that causes a plane to lose height suddenly
- air pressure
- the pressure exerted by the atmosphere
- air
- a slight wind (usually refreshing)
- airstream
- a relatively well-defined prevailing wind
- airstream
- the flow of air that is driven backwards by an aircraft propeller
- allotropism
- the phenomenon of an element existing in two or more physical forms
- alluvial cone
- a fan-shaped deposit where a fast flowing stream flattens out
- alluviation
- the phenomenon of sediment or gravel accumulating
- alluvion
- the rising of a body of water and its overflowing onto normally dry land
- alpha radiation
- the radiation of alpha particles during radioactive decay
- alpha rhythm
- the normal brainwave in the electroencephalogram of a person who is awake but relaxed; occurs with a frequency of 8-12 hertz
- alternation of generations
- the alternation of two or more different forms in the life cycle of a plant or animal
- alternative energy
- energy derived from sources that do not use up natural resources or harm the environment
- amperage
- the strength of an electrical current measured in amperes
- amplitude distortion
- distortion that occurs when the output signal does not have a linear relation to the input signal
- 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
- annual parallax
- the parallax of a celestial body using two points in the earth's orbit around the sun as the baseline
- annual ring
- an annual formation of wood in plants as they grow
- antiferromagnetism
- magnetic field creates parallel but opposing spins; varies with temperature
- antitrade
- winds blowing from west to east and lying above the trade winds in the tropics
- antitrades
- wind in the upper atmosphere blowing above but in the opposite direction from the trade winds
- apoptosis
- a type of cell death in which the cell uses specialized cellular machinery to kill itself; a cell suicide mechanism that enables metazoans to control cell number and eliminate cells that threaten the animal's survival
- apparent motion
- an optical illusion of motion produced by viewing a rapid succession of still pictures of a moving object
- arc
- electrical conduction through a gas in an applied electric field
- arterial pressure
- the pressure of the circulating blood on the arteries
- atmospheric condition
- the atmospheric conditions that comprise the state of the atmosphere in terms of temperature and wind and clouds and precipitation
- atmospheric electricity
- electrical discharges in the atmosphere
- atmospheric phenomenon
- a physical phenomenon associated with the atmosphere
- atomic energy
- the energy released by a nuclear reaction
- atomic power
- nuclear energy regarded as a source of electricity for the power grid (for civilian use)
- atomic spectrum
- (physics) a spectrum of radiation caused by electron transitions within an atom; the series of spectrum lines is characteristic of the element
- attraction
- the force by which one object attracts another
- aureole
- the outermost region of the sun's atmosphere; visible as a white halo during a solar eclipse
- aurora
- an atmospheric phenomenon consisting of bands of light caused by charged solar particles following the earth's magnetic lines of force
- aurora australis
- the aurora of the southern hemisphere
- aurora borealis
- the aurora of the northern hemisphere
- autofluorescence
- self-induced fluorescence
- bad luck
- an unpredictable outcome that is unfortunate
- ballistic trajectory
- the trajectory of an object in free flight
- bandwagon effect
- the phenomenon of a popular trend attracting even greater popularity
- barometric pressure
- atmospheric pressure as indicated by a barometer
- beam
- a column of light (as from a beacon)
- beam
- a group of nearly parallel lines of electromagnetic radiation
- beat
- a single pulsation of an oscillation produced by adding two waves of different frequencies; has a frequency equal to the difference between the two oscillations
- beta radiation
- radiation of beta particles during radioactive decay
- beta rhythm
- the normal brainwave in the encephalogram of a person who is awake and alert; occurs with a frequency between 12 and 30 hertz
- binding energy
- the energy required to separate particles from a molecule or atom or nucleus; equals the mass defect
- bioelectricity
- electric phenomena in animals or plants
- biology
- characteristic life processes and phenomena of living organisms
- bioluminescence
- luminescence produced by physiological processes (as in the firefly)
- birefringence
- splitting a ray into two parallel rays polarized perpendicularly
- bise
- a dry cold north wind in southeastern France
- blackbody radiation
- 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
- blast
- a strong current of air
- blizzard
- a storm with widespread snowfall accompanied by strong winds
- blood pressure
- 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
- bloom
- a powdery deposit on a surface
- blue jet
- atmospheric discharges (lasting 10 msec) bursting from the tops of giant storm clouds in blue cones that widen as they flash upward
- bluster
- a violent gusty wind
- bolide
- an especially luminous meteor (sometimes exploding)
- bolt
- a discharge of lightning accompanied by thunder
- bond
- an electrical force linking atoms
- boreas
- a wind that blows from the north
- boundary layer
- the layer of slower flow of a fluid past a surface
- brain death
- death when respiration and other reflexes are absent; consciousness is gone; organs can be removed for transplantation before the heartbeat stops
- brain wave
- (neurophysiology) rapid fluctuations of voltage between parts of the cerebral cortex that are detectable with an electroencephalograph
- branch
- a natural consequence of development
- breaking point
- the degree of tension or stress at which something breaks
- breath
- a slight movement of the air
- brisance
- the shattering or crushing effect of a sudden release of energy as in an explosion
- Brownian movement
- the random motion of small particles suspended in a gas or liquid
- brush discharge
- discharge between electrodes creating visible streamers of ionized particles
- butterfly effect
- the phenomenon whereby a small change at one place in a complex system can have large effects elsewhere, e.g., a butterfly flapping its wings in Rio de Janeiro might change the weather in Chicago
- byproduct
- a secondary and sometimes unexpected consequence
- calm
- wind moving at less than 1 knot; 0 on the Beaufort scale
- candle flame
- the light provided by a burning candle
- capacitance
- an electrical phenomenon whereby an electric charge is stored
- capillarity
- a phenomenon associated with surface tension and resulting in the elevation or depression of liquids in capillaries
- carrier
- a radio wave that can be modulated in order to transmit a signal
- catabatic wind
- a wind caused by the downward motion of cold air
- cataclysm
- a sudden violent change in the earth's surface
- cathode ray
- a beam of electrons emitted by the cathode of an electrical discharge tube
- cell death
- (physiology) the normal degeneration and death of living cells (as in various epithelial cells)
- centrifugal force
- the outward force on a body moving in a curved path around another body
- centripetal force
- the inward force on a body moving in a curved path around another body
- chain lightning
- a form of lightning that moves rapidly in a zigzag path with one end divided (fork-like)
- champion lode
- the main vein of ore in a deposit
- chance
- an unknown and unpredictable phenomenon that causes an event to result one way rather than another
- change
- the result of alteration or modification
- chaos
- the formless and disordered state of matter before the creation of the cosmos
- charge
- the quantity of unbalanced electricity in a body (either positive or negative) and construed as an excess or deficiency of electrons
- chatter mark
- marks on a glaciated rock caused by the movement of a glacier
- chemical energy
- that part of the energy in a substance that can be released by a chemical reaction
- chemical phenomenon
- any natural phenomenon involving chemistry (as changes to atoms or molecules)
- chemiluminescence
- luminescence resulting from a chemical reaction as the oxidation of luciferin in fireflies
- chinook
- a warm dry wind blowing down the eastern slopes of the Rockies
- chop
- the irregular motion of waves (usually caused by wind blowing in a direction opposite to the tide)
- chromatic aberration
- an optical aberration in which the image has colored fringes
- circulation
- movement through a circuit; especially the movement of blood through the heart and blood vessels
- cloud
- any collection of particles (e.g., smoke or dust) or gases that is visible
- cloudburst
- a heavy rain
- CMBR
- (cosmology) the cooled remnant of the hot big bang that fills the entire universe and can be observed today with an average temperature of about 2.725 kelvin
- coattails effect
- (politics) the consequence of one popular candidate in an election drawing votes for other members of the same political party
- cohesion
- (physics) the intermolecular force that holds together the molecules in a solid or liquid
- cold front
- the front of an advancing mass of colder air
- cold wave
- a wave of unusually cold weather
- cold weather
- a period of unusually cold weather
- color force
- (physics) the interaction that binds protons and neutrons together in the nuclei of atoms; mediated by gluons
- color spectrum
- the distribution of colors produced when light is dispersed by a prism
- compartment pressure
- the air pressure maintained in an air-tight compartment (as in an aircraft)
- condensate
- atmospheric moisture that has condensed because of cold
- conductance
- a material's capacity to conduct electricity; measured as the reciprocal of electrical resistance
- conduction
- the transmission of heat or electricity or sound
- consequence
- a phenomenon that follows and is caused by some previous phenomenon
- continental drift
- the gradual movement and formation of continents (as described by plate tectonics)
- coordinate bond
- a covalent bond in which both electrons are provided by one of the atoms
- 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
- 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
- corona
- one or more circles of light seen around a luminous object
- corpuscular radiation
- 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)
- corpuscular-radiation pressure
- the minute pressure exerted on a surface normal to the direction of propagation of a wave
- cosmic dust
- clouds of particles or gases occurring throughout interstellar space
- cosmic radiation
- radiation coming from outside the solar system
- 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
- counterglow
- 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
- covalent bond
- a chemical bond that involves sharing a pair of electrons between atoms in a molecule
- cross-link
- a side bond that links two adjacent chains of atoms in a complex molecule
- crosswind
- wind blowing across the path of a ship or aircraft
- crystallisation
- the formation of crystals
- current electricity
- a flow of electric charge
- current
- a flow of electricity through a conductor
- cyclone
- a violent rotating windstorm
- cyclosis
- the circulation of cytoplasm within a cell
- daylight
- light during the daytime
- DC
- an electric current that flows in one direction steadily
- death
- the permanent end of all life functions in an organism or part of an organism
- debacle
- flooding caused by a tumultuous breakup of ice in a river during the spring or summer
- 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
- decay
- the organic phenomenon of rotting
- dehiscence
- (biology) release of material by splitting open of an organ or tissue; the natural bursting open at maturity of a fruit or other reproductive body to release seeds or spores or the bursting open of a surgically closed wound
- delta rhythm
- the normal brainwave in the encephalogram of a person in deep dreamless sleep; occurs with high voltage and low frequency (1 to 4 hertz)
- dent
- an appreciable consequence (especially a lessening)
- depolarisation
- a loss of polarity or polarization
- desquamation
- loss of bits of outer skin by peeling or shedding or coming off in scales
- 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
- diamond dust
- small crystals of ice
- diapedesis
- passage of blood cells (especially white blood cells) through intact capillary walls and into the surrounding tissue
- diastolic pressure
- the blood pressure (as measured by a sphygmomanometer) after the contraction of the heart while the chambers of the heart refill with blood
- dichroism
- pleochroism of a crystal so that it exhibits two different colors when viewed from two different directions
- dielectric heating
- heating of an insulator by a high-frequency electric field
- diffraction
- when light passes sharp edges or goes through narrow slits the rays are deflected and produce fringes of light and dark bands
- digenesis
- alternation of sexual and asexual generations
- dimorphism
- (biology) the existence of two forms of individual within the same animal species (independent of sex differences)
- dimorphism
- (chemistry) the property of certain substances that enables them to exist in two distinct crystalline forms
- dipole moment
- the moment of a dipole
- distortion
- a change (usually undesired) in the waveform of an acoustic or analog electrical signal; the difference between two measurements of a signal (as between the input and output signal)
- diurnal parallax
- the parallax of a celestial body using two points on the surface of the earth as the earth rotates
- doldrums
- a belt of calms and light winds between the northern and southern trade winds of the Atlantic and Pacific
- dominance
- the organic phenomenon in which one of a pair of alleles present in a genotype is expressed in the phenotype and the other allele of the pair is not
- domino effect
- the consequence of one event setting off a chain of similar events (like a falling domino causing a whole row of upended dominos to fall)
- Doppler effect
- change in the apparent frequency of a wave as observer and source move toward or away from each other
- double bond
- a covalent bond in which two pairs of electrons are shared between two atoms
- downdraft
- a strong downward air current
- downfall
- the falling to earth of any form of water (rain or snow or hail or sleet or mist)
- draft
- a current of air (usually coming into a chimney or room or vehicle)
- drag
- the phenomenon of resistance to motion through a fluid
- drift
- a force that moves something along
- drizzle
- very light rain; stronger than mist but less than a shower
- dust cloud
- a cloud of dust suspended in the air
- dust devil
- a miniature whirlwind strong enough to whip dust and leaves and litter into the air
- dust storm
- a windstorm that lifts up clouds of dust or sand
- east wind
- a wind from the east
- El Nino
- (oceanography) a warm ocean current that flows along the equator from the date line and south off the coast of Ecuador at Christmas time
- El Nino southern oscillation
- a more intense El Nino that occurs every few years when the welling up of cold nutrient-rich water does not occur; kills plankton and fish and affects weather patterns
- elan vital
- (biology) a hypothetical force (not physical or chemical) once thought by Henri Bergson to cause the evolution and development of organisms
- elastance
- the reciprocal of capacitance
- elastic energy
- potential energy that is stored when a body is deformed (as in a coiled spring)
- electric dipole moment
- the dipole moment in an electric dipole
- electric field
- a field of force surrounding a charged particle
- electric potential
- the difference in electrical charge between two points in a circuit expressed in volts
- electric power
- the product of voltage and current
- electric resistance
- a material's opposition to the flow of electric current; measured in ohms
- electric storm
- a storm resulting from strong rising air currents; heavy rain or hail along with thunder and lightning
- electrical conduction
- the passage of electricity through a conductor
- electrical disturbance
- electrical signals produced by unwanted sources (atmospherics or receiver noise or unwanted transmitters)
- electrical energy
- energy made available by the flow of electric charge through a conductor
- electrical line of force
- a line of force in an electrical field
- electrical phenomenon
- a physical phenomenon involving electricity
- electricity
- a physical phenomenon associated with stationary or moving electrons and protons
- electromagnetic interaction
- an interaction between charged elementary particles that is intermediate in strength between the strong and weak interactions; mediated by photons
- electromagnetic radiation
- radiation consisting of waves of energy associated with electric and magnetic fields resulting from the acceleration of an electric charge
- electromagnetic spectrum
- the entire frequency range of electromagnetic waves
- electromagnetism
- magnetism produced by an electric current
- electromotive force
- the rate at which energy is drawn from a source that produces a flow of electricity in a circuit; expressed in volts
- electrostatic bond
- a chemical bond in which one atom loses an electron to form a positive ion and the other atom gains an electron to form a negative ion
- electrostatic charge
- the electric charge at rest on the surface of an insulated body (which establishes and adjacent electrostatic field)
- electrostatic field
- electric field associated with static electric charges
- elements
- violent or severe weather (viewed as caused by the action of the four elements)
- elves
- 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
- emission spectrum
- spectrum of electromagnetic radiation emitted by a self-luminous source
- endogeny
- a geological phenomenon below the surface of the earth
- energy
- any source of usable power
- energy level
- a definite stable energy that a physical system can have; used especially of the state of electrons in atoms or molecules
- energy
- (physics) a thermodynamic quantity equivalent to the capacity of a physical system to do work; the units of energy are joules or ergs
- engine
- something used to achieve a purpose
- epiphenomenon
- a secondary phenomenon that is a by-product of another phenomenon
- equatorial current
- any of the ocean currents that flow westward at the equator
- equinoctial storm
- a violent rainstorm near the time of an equinox
- even chance
- an unpredictable phenomenon
- event
- a phenomenon located at a single point in space-time; the fundamental observational entity in relativity theory
- evoked potential
- the electrical response of the central nervous system produced by an external stimulus
- exchange
- chemical process in which one atom or ion or group changes places with another
- exfoliation
- the peeling off in flakes or scales of bark or dead skin
- facilitation
- (neurophysiology) phenomenon that occurs when two or more neural impulses that alone are not enough to trigger a response in a neuron combine to trigger an action potential
- facula
- a bright spot on a planet
- facula
- a large bright spot on the sun's photosphere occurring most frequently in the vicinity of sunspots
- fair weather
- moderate weather; suitable for outdoor activities
- fallout
- any adverse and unwanted secondary effect
- fata morgana
- a mirage in the Strait of Messina (attributed to the Arthurian sorcerer Morgan le Fay)
- ferrimagnetism
- a phenomenon in ferrites where there can be incomplete cancellation of antiferromagnetic arranged spins giving a net magnetic moment
- 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
- field line
- an imaginary line in a field of force; direction of the line at any point is the direction of the force at that point
- field
- the space around a radiating body within which its electromagnetic oscillations can exert force on another similar body not in contact with it
- fine spray
- precipitation in very small drops
- fine structure
- the presence of groups of closely spaced spectrum lines observed in the atomic spectrum of certain elements
- firelight
- the light of a fire (especially in a fireplace)
- firestorm
- a storm in which violent winds are drawn into the column of hot air rising over a severely bombed area
- flake
- a crystal of snow
- flare
- am unwanted reflection in an optical system (or the fogging of an image that is caused by such a reflection)
- flare
- a sudden eruption of intense high-energy radiation from the sun's surface; associated with sunspots and radio interference
- flash flood
- a sudden local flood of great volume and short duration
- flashover
- an unintended electric discharge (as over or around an insulator)
- flight
- the path followed by an object moving through space
- floatation
- the phenomenon of floating (remaining on the surface of a liquid without sinking)
- floodhead
- a wall of water rushing ahead of the flood
- fluke
- a stroke of luck
- fluorescence
- light emitted during absorption of radiation of some other (invisible) wavelength
- flurry
- a light brief snowfall and gust of wind (or something resembling that)
- flux
- the lines of force surrounding a permanent magnet or a moving charged particle
- focal point
- a point of convergence of light (or other radiation) or a point from which it diverges
- foehn
- a warm dry wind that blows down the northern slopes of the Alps
- fog
- droplets of water vapor suspended in the air near the ground
- fogbank
- a large mass of fog on the sea (as seen from a distance)
- food chain
- (ecology) a community of organisms where each member is eaten in turn by another member
- food cycle
- (ecology) a community of organisms where there are several interrelated food chains
- food pyramid
- (ecology) a hierarchy of food chains with the principal predator at the top; each level preys on the level below
- force
- (physics) the influence that produces a change in a physical quantity
- force per unit area
- the force applied to a unit area of surface; measured in pascals (SI unit) or in dynes (cgs unit)
- fortune
- an unknown and unpredictable phenomenon that leads to a favorable outcome
- freeze
- weather cold enough to cause freezing
- fresh breeze
- wind moving 19-24 knots; 5 on the Beaufort scale
- fresh gale
- wind moving 39-46 knots; 8 on the Beaufort scale
- friar's lantern
- a pale light sometimes seen at night over marshy ground
- friction
- the resistance encountered when one body is moved in contact with another
- fringe
- one of the light or dark bands produced by the interference and diffraction of light
- front
- (meteorology) the atmospheric phenomenon created at the boundary between two different air masses
- frost heave
- upthrust of ground or pavement caused by the freezing of moist soil
- fume
- a cloud of fine particles suspended in a gas
- fundamental interaction
- (physics) the transfer of energy between elementary particles or between an elementary particle and a field or between fields; mediated by gauge bosons
- gale
- a strong wind moving 45-90 knots; force 7 to 10 on Beaufort scale
- galvanism
- electricity produced by chemical action
- gamma radiation
- electromagnetic radiation emitted during radioactive decay and having an extremely short wavelength
- gangrene
- the localized death of living cells (as from infection or the interruption of blood supply)
- gas pressure
- the pressure exerted by a gas
- gaslight
- light yielded by the combustion of illuminating gas
- gene expression
- conversion of the information encoded in a gene first into messenger RNA and then to a protein
- gentle breeze
- wind moving 8-12 knots; 3 on the Beaufort scale
- geological phenomenon
- a natural phenomenon involving the structure or composition of the earth
- geothermal energy
- energy derived from the heat in the interior of the earth
- glow
- a steady even light without flames
- glow
- the amount of electromagnetic radiation leaving or arriving at a point on a surface
- glow
- the phenomenon of light emission by a body as its temperature is raised
- gravitation
- (physics) the force of attraction between all masses in the universe; especially the attraction of the earth's mass for bodies near its surface
- gravitational field
- a field of force surrounding a body of finite mass
- gravitational interaction
- a weak interaction between particles that results from their mass; mediated by gravitons
- gravity-assist
- (spaceflight) a trajectory that passes close to a planetary body in order to gain energy from its gravitational field
- 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
- greening
- the phenomenon of vitality and freshness being restored
- ground effect
- apparent increase in aerodynamic lift experienced by an aircraft flying close to the ground
- ground wave
- a radio wave propagated on or near the earth's surface
- Gulf stream
- a warm ocean current that flows from the Gulf of Mexico northward through the Atlantic Ocean
- gun smoke
- smoke created by the firing of guns
- hail
- precipitation of ice pellets when there are strong rising air currents
- hailstorm
- a storm during which hail falls
- half-light
- a greyish light (as at dawn or dusk or in dim interiors)
- halo
- a circle of light around the sun or moon
- harmattan
- a dusty wind from the Sahara that blows toward the western coast of Africa during the winter
- harvest
- the consequence of an effort or activity
- haze
- atmospheric moisture or dust or smoke that causes reduced visibility
- head
- the pressure exerted by a fluid
- head sea
- a sea in which the waves are running directly against the course of the ship
- headwind
- wind blowing opposite to the path of a ship or aircraft
- heat of condensation
- heat liberated by a unit mass of gas at its boiling point as it condenses into a liquid
- heat of dissociation
- the heat required for a fluid substance to break up into simpler constituents
- heat of formation
- the heat evolved or absorbed during the formation of one mole of a substance from its component elements
- 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
- heat of solidification
- heat liberated by a unit mass of liquid at its freezing point when it solidifies
- heat of solution
- the heat evolved or absorbed when one mole of a substance is dissolved in a large volume of a solvent
- heat of sublimation
- heat absorbed by a unit mass of material when it changes from a solid to a gaseous state
- heat of transformation
- heat absorbed or radiated during a change of phase at a constant temperature and pressure
- 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
- heat ray
- a ray that produces a thermal effect
- heat wave
- a wave of unusually hot weather
- heat
- a form of energy that is transferred by a difference in temperature
- Hertzian wave
- a former name for a radio wave; an electromagnetic wave of radio frequency generated by oscillations in an electric circuit
- high beam
- the beam of a car's headlights that provides distant illumination
- high wind
- a very strong wind
- histocompatibility
- condition in which the cells of one tissue can survive in the presence of cells of another tissue
- horizontal parallax
- the maximum parallax observed when the celestial body is at the horizon
- hot weather
- a period of unusually high temperatures
- hurricane
- a severe tropical cyclone usually with heavy rains and winds moving at 63-136 knots (12 on the Beaufort scale)
- hydroelectricity
- electricity produced by water power
- 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
- hydrostatic head
- 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
- 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
- ice fog
- a dense winter fog containing ice particles
- ice storm
- a storm with freezing rain that leaves everything glazed with ice
- impact
- a forceful consequence; a strong effect
- incidence
- the striking of a light beam on a surface
- inductance
- an electrical phenomenon whereby an electromotive force (EMF) is generated in a closed circuit by a change in the flow of current
- inertia
- (physics) the tendency of a body to maintain its state of rest or uniform motion unless acted upon by an external force
- influence
- the effect of one thing (or person) on another
- infrared ray
- a ray of infrared radiation; produces a thermal effect (as from an infrared lamp)
- infrared spectrum
- the spectrum of infrared radiation
- infrared
- electromagnetic radiation with wavelengths longer than visible light but shorter than radio waves
- insolation
- incident solar radiation
- instantaneous sound pressure
- the difference between the instantaneous pressure at a point in a sound field and the average pressure at that point
- interfacial surface tension
- surface tension at the surface separating two non-miscible liquids
- interreflection
- reciprocal reflection between two reflecting surfaces
- interrupt
- a signal that temporarily stops the execution of a program so that another procedure can be carried out
- inversion
- the layer of air near the earth is cooler than an overlying layer
- ion beam
- a beam of ions moving in the same direction at the same speed
- ionizing radiation
- high-energy radiation capable of producing ionization in substances through which it passes
- ionospheric wave
- a sky wave that is reflected by the ionosphere
- IOP
- pressure exerted by the fluids inside the eyeball; regulated by resistance to the outward flow of aqueous humor
- jet propulsion
- propulsion by means of the discharge of a jet of fluid toward the rear
- jet stream
- 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
- juice
- electric current
- K.E.
- the mechanical energy that a body has by virtue of its motion
- khamsin
- an oppressively hot southerly wind from the Sahara that blows across Egypt in the spring
- knock-on effect
- a secondary or incidental effect
- Kuroshio current
- a warm ocean current that flows northeastwardly off the coast of Japan into the northern Pacific ocean
- laminar flow
- nonturbulent streamline flow in parallel layers (laminae)
- lamplight
- light from a lamp
- languor
- oppressively still air
- laser beam
- a beam of light generated by a laser
- levanter
- an easterly wind in the western Mediterranean area
- leverage
- the mechanical advantage gained by being in a position to use a lever
- levitation
- the phenomenon of a person or thing rising into the air by apparently supernatural means
- life
- the organic phenomenon that distinguishes living organisms from nonliving ones
- life cycle
- a series of stages through which an organism passes between recurrences of a primary stage
- light air
- wind moving 1-3 knots; 1 on the Beaufort scale
- light breeze
- wind moving 4-7 knots; 2 on the Beaufort scale
- light
- (physics) electromagnetic radiation that can produce a visual sensation
- lightning
- abrupt electric discharge from cloud to cloud or from cloud to earth accompanied by the emission of light
- line
- a single frequency (or very narrow band) of radiation in a spectrum
- line spectrum
- a spectrum in which energy is concentrated at particular wavelengths; produced by excited atoms and ions as they fall back to a lower energy level
- line squall
- a squall advancing along a front that forms a definite line
- load
- the power output of a generator or power plant
- load
- a deposit of valuable ore occurring within definite boundaries separating it from surrounding rocks
- long wave
- a radio wave with a wavelength longer than a kilometer (a frequency below 300 kilohertz)
- 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
- low beam
- the beam of a car's headlights that provides illumination for a short distance
- luminescence
- light not due to incandescence; occurs at low temperatures
- luminous energy
- the energy associated with visible light
- macula
- a cooler darker spot appearing periodically on the sun's photosphere; associated with a strong magnetic field
- magnetic attraction
- attraction for iron; associated with electric currents as well as magnets; characterized by fields of force
- magnetic dipole moment
- (physics) a current loop gives rise to a magnetic field characteristic of a magnetic dipole
- magnetic line of force
- a line of force in a magnetic field
- magnetic moment
- the torque exerted on a magnet or dipole when it is placed in a magnetic field
- magnetic resonance
- resonance of electrons or atoms or molecules or nuclei to radiation frequencies as a result of space quantization in a magnetic field
- magnetomotive force
- the force that produces magnetic flux
- 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
- mass defect
- the amount by which the mass of an atomic nucleus is less than the sum of the masses of its constituent particles
- mass spectrum
- a distribution of ions as shown by a mass spectrograph or a mass spectrometer
- mechanical energy
- energy in a mechanical form
- mechanical phenomenon
- a physical phenomenon associated with the equilibrium or motion of objects
- medium wave
- a radio wave with a wavelength between 100 and 1000 meters (a frequency between 300 kilohertz and 3000 kilohertz)
- metallic bond
- a chemical bond in which electrons are shared over many nuclei and electronic conduction occurs
- metempsychosis
- after death the soul begins a new cycle of existence in another human body
- meteor shower
- a transient shower of meteors when a meteor swarm enters the earth's atmosphere
- meteor
- 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
- microwave
- a short electromagnetic wave (longer than infrared but shorter than radio waves); used for radar and microwave ovens and for transmitting telephone, facsimile, video and data
- microwave spectrum
- the part of the electromagnetic spectrum corresponding to microwaves
- midnight sun
- the sun visible at midnight (inside the Arctic or Antarctic Circles)
- mirage
- an optical illusion in which atmospheric refraction by a layer of hot air distorts or inverts reflections of distant objects
- mist
- a thin fog with condensation near the ground
- mistral
- a strong north wind that blows in France during the winter
- mock sun
- a bright spot on the parhelic circle; caused by diffraction by ice crystals
- moderate breeze
- wind moving 13-18 knots; 4 on the Beaufort scale
- moderate gale
- wind moving 32-38 knots; 7 on the Beaufort scale
- moment
- a turning force produced by an object acting at a distance (or a measure of that force)
- moment of a couple
- given two equal and opposite forces, the product of the force and the distance between them
- moment of inertia
- the tendency of a body to resist angular acceleration
- monsoon
- a seasonal wind in southern Asia; blows from the southwest (bringing rain) in summer and from the northeast in winter
- monsoon
- any wind that changes direction with the seasons
- Moon
- the light of the Moon
- moon ray
- a ray of moonlight
- mushroom
- a large cloud of rubble and dust shaped like a mushroom and rising into the sky after an explosion (especially of a nuclear bomb)
- mutual induction
- generation of electromotive forces in each other by two adjacent circuits
- myonecrosis
- localized death of muscle cell fibers
- natural phenomenon
- all phenomena that are not artificial
- negative charge
- having a surplus of electrons; having a lower electric potential
- neutron radiation
- radiation of neutrons (as by a neutron bomb)
- NMR
- resonance of protons to radiation in a magnetic field
- Noah and the Flood
- (Biblical) the great deluge that is said in the Book of Genesis to have occurred in the time of Noah; it was brought by God upon the earth because of the wickedness of human beings
- noreaster
- a storm blowing from the northeast
- North Equatorial Current
- an equatorial current that flows west across the Pacific just north of the equator
- northwest wind
- a wind from the northwest
- nuclear propulsion
- 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)
- nuclear resonance
- the resonance absorption of a gamma ray by a nucleus identical to the nucleus that emitted the gamma ray
- nuclear winter
- a long period of darkness and extreme cold that scientists predict would follow a full-scale nuclear war; a layer of dust and smoke in the atmosphere would cover the earth and block the rays of the sun; most living organisms would perish
- occluded front
- (meteorology) a composite front when colder air surrounds a mass of warm air and forces it aloft
- ocean current
- the steady flow of surface ocean water in a prevailing direction
- ohmage
- the ohmic resistance of a conductor
- oil pressure
- pressure that keeps oil on the moving parts of an internal-combustion engine
- opacity
- the phenomenon of not permitting the passage of electromagnetic radiation
- optical illusion
- an optical phenomenon that results in a false or deceptive visual impression
- optical opacity
- opacity to light
- optical phenomenon
- a physical phenomenon related to or involving light
- organic phenomenon
- (biology) a natural phenomenon involving living plants and animals
- osmotic pressure
- (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
- overpressure
- a transient air pressure greater than the surrounding atmospheric pressure
- overstrain
- too much strain
- P.E.
- the mechanical energy that a body has by virtue of its position; stored energy
- parallax
- the apparent displacement of an object as seen from two different points that are not on a line with the object
- paramagnetism
- materials like aluminum or platinum become magnetized in a magnetic field but it disappears when the field is removed
- parhelic circle
- a luminous halo parallel to the horizon at the altitude of the sun; caused by ice crystals in the atmosphere
- particle beam
- a collimated flow of particles (atoms or electrons or molecules)
- pea soup
- a heavy thick yellow fog
- peptide bond
- the primary linkage of all protein structures; the chemical bond between the carboxyl groups and amino groups that unites a peptide
- perturbation
- (physics) a secondary influence on a system that causes it to deviate slightly
- Peruvian current
- a cold ocean current that flows north along the Pacific Coast of South America before turning west
- phosphorescence
- a fluorescence that persists after the bombarding radiation has ceased
- photochemical exchange
- an exchange produced by the chemical action of radiant energy (especially light)
- photoconduction
- change in the electrical conductivity of a substance as a result of absorbing electromagnetic radiation
- photoelectricity
- electricity generated by light or affected by light
- photoemission
- an emission of photoelectrons (especially from a metallic surface)
- physical phenomenon
- a natural phenomenon involving the physical properties of matter and energy
- piezo effect
- 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
- placebo effect
- any effect that seems to be a consequence of administering a placebo; the change is usually beneficial and is assumed result from the person's faith in the treatment or preconceptions about what the experimental drug was supposed to do; pharmacologists were the first to talk about placebo effects but now the idea has been generalized to many situations having nothing to do with drugs
- pleochroism
- the phenomenon of different colors appearing when certain crystals are viewed from different directions
- pleomorphism
- (biology) the appearance of two or more distinctly different forms in the life cycle of some organisms
- pleomorphism
- (chemistry) the existence of different kinds of crystal of the same chemical compound
- polarisation
- the phenomenon in which waves of light or other radiation are restricted in direction of vibration
- polymorphism
- (genetics) the genetic variation within a population that natural selection can operate on
- polymorphism
- (biology) the existence of two or more forms of individuals within the same animal species (independent of sex differences)
- position effect
- (genetics) the effect on the expression of a gene that is produced by changing its location in a chromosome
- positive charge
- having a deficiency of electrons; having a higher electric potential
- power
- (physics) the rate of doing work; measured in watts (= joules/second)
- prevailing westerly
- the winds from the west that occur in the temperate zones of the Earth
- prevailing wind
- the predominant wind direction
- product
- a consequence of someone's efforts or of a particular set of circumstances
- propagation
- the movement of a wave through a medium
- propulsion
- a propelling force
- puff
- a short light gust of air
- pull
- the force used in pulling
- pulmonary circulation
- circulation of blood between the heart and the lungs
- pulsation
- a periodically recurring phenomenon that alternately increases and decreases some quantity
- purchase
- a means of exerting influence or gaining advantage
- push
- the force used in pushing
- pyroelectricity
- generation of an electric charge on certain crystals (such as tourmaline) as a result of a change in temperature
- radiant energy
- energy that is transmitted in the form of (electromagnetic) radiation; energy that exists in the absence of matter
- radiation
- energy that is radiated or transmitted in the form of rays or waves or particles
- radiation field
- a field that represents the energy lost from the radiator to space
- radio emission
- an electromagnetic wave with a wavelength between 0.5 cm to 30,000 m
- radio signal
- a radio wave used to transmit and receive messages
- radio spectrum
- the entire spectrum of electromagnetic frequencies used for communications; includes frequencies used for radio and radar and television
- radio-opacity
- opacity to X-rays or other radiation
- rain shower
- a brief period of precipitation
- rain
- water falling in drops from vapor condensed in the atmosphere
- raindrop
- a drop of rain
- rainstorm
- a storm with rain
- reactance
- opposition to the flow of electric current resulting from inductance and capacitance (rather than resistance)
- reaction
- (mechanics) the equal and opposite force that is produced when any force is applied to a body
- reaction
- a response that reveals a person's feelings or attitude
- 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
- recognition
- (biology) the ability of one molecule to attach to another molecule that has a complementary shape
- red shift
- (astronomy) a shift in the spectra of very distant galaxies toward longer wavelengths (toward the red end of the spectrum); generally interpreted as evidence that the universe is expanding
- red sprites
- 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)
- reflection
- the phenomenon of a propagating wave (light or sound) being thrown back from a surface
- refraction
- the change in direction of a propagating wave (light or sound) when passing from one medium to another
- rejection
- (medicine) an immunological response that refuses to accept substances or organisms that are recognized as foreign
- reluctance
- (physics) opposition to magnetic flux (analogous to electric resistance)
- repercussion
- a remote or indirect consequence of some action
- repulsion
- the force by which bodies repel one another
- resistance
- any mechanical force that tends to retard or oppose motion
- resolution
- (computer science) the number of pixels per square inch on a computer-generated display; the greater the resolution, the better the picture
- resolution
- the ability of a microscope or telescope to measure the angular separation of images that are close together
- resonance
- a vibration of large amplitude produced by a relatively small vibration near the same frequency of vibration as the natural frequency of the resonating system
- resonance
- an excited state of a stable particle causing a sharp maximum in the probability of absorption of electromagnetic radiation
- response
- a result
- 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
- resting potential
- the potential difference between the two sides of the membrane of a nerve cell when the cell is not conducting an impulse
- rocket propulsion
- reaction propulsion using stored oxygen for combustion; used where there is insufficient atmospheric oxygen
- Saint Elmo's light
- an electrical discharge accompanied by ionization of surrounding atmosphere
- samiel
- a violent hot sand-laden wind on the deserts of Arabia and North Africa
- sandblast
- a blast of wind laden with sand
- Santa Ana
- a strong hot dry wind that blows in winter from the deserts of southern California toward the Pacific Coast
- scattering
- a light shower that falls in some locations and not others nearby
- scintillation
- (physics) a flash of light that is produced in a phosphor when it absorbs a photon or ionizing particle
- scorcher
- an extremely hot day
- sea
- turbulent water with swells of considerable size
- sea breeze
- a cooling breeze from the sea (during the daytime)
- sea-level pressure
- the atmospheric pressure reduced by a formula to the pressure at sea level
- self-induction
- generation of an electromotive force (EMF) in a circuit by changing the current in that circuit; usually measured in henries
- serendipity
- good luck in making unexpected and fortunate discoveries
- sex linkage
- an association between genes in sex chromosomes that makes some characteristics appear more frequently in one sex than in the other
- shear
- (physics) a deformation of an object in which parallel planes remain parallel but are shifted in a direction parallel to themselves
- short wave
- a radio wave with a wavelength less than 100 meters (a frequency greater than 3 megahertz)
- signal
- an electric quantity (voltage or current or field strength) whose modulation represents coded information about the source from which it comes
- skin effect
- the tendency of high-frequency alternating current to distribute near the surface of a conductor
- sky glow
- illumination of the night sky in urban areas
- sky wave
- 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
- sleet
- partially melted snow (or a mixture of rain and snow)
- smother
- a stifling cloud of smoke
- snow
- precipitation falling from clouds in the form of ice crystals
- SNP
- (genetics) genetic variation in a DNA sequence that occurs when a single nucleotide in a genome is altered; SNPs are usually considered to be point mutations that have been evolutionarily successful enough to recur in a significant proportion of the population of a species
- solar energy
- energy from the sun that is converted into thermal or electrical energy
- solar gravity
- the gravity of the sun
- solar magnetic field
- the magnetic field of the sun
- solar parallax
- the angle subtended by the mean equatorial radius of the Earth at a distance of one astronomical unit
- solar prominence
- large eruptions of luminous hydrogen gas that rise thousands of kilometers above the chromosphere
- solar radiation
- radiation from the sun
- solar wind
- a stream of protons moving radially from the sun
- sonic barrier
- the increase in aerodynamic drag as an airplane approaches the speed of sound
- sou'easter
- a strong wind from the southeast
- sound
- mechanical vibrations transmitted by an elastic medium
- South Equatorial Current
- an equatorial current that flows west across the Pacific just south of the equator
- south wind
- a wind from the south
- southwester
- a strong wind from the southwest
- specific heat
- the heat required to raise the temperature of one gram of a substance one degree centigrade
- spectrum
- an ordered array of the components of an emission or wave
- speech spectrum
- the average sound spectrum for the human voice
- spherical aberration
- an optical aberration resulting in a distorted image
- spillover
- (economics) any indirect effect of public expenditure
- squall
- sudden violent winds; often accompanied by precipitation
- squall line
- a cold front along which squalls or thunderstorms are likely
- starlight
- the light of the stars
- static electricity
- electricity produced by friction
- stellar parallax
- the heliocentric parallax of a star
- storm
- a violent weather condition with winds 64-72 knots (11 on the Beaufort scale) and precipitation and thunder and lightning
- strain
- (physics) deformation of a physical body under the action of applied forces
- streamer
- light that streams
- streamline flow
- flow of a gas or liquid in which the velocity at any point is relatively steady
- stress
- (physics) force that produces strain on a physical body
- strong breeze
- wind moving 25-31 knots; 6 on the Beaufort scale
- strong gale
- wind moving 47-54 knots; 9 on the Beaufort scale
- suction
- a force over an area produced by a pressure difference
- sultriness
- oppressively hot and humid weather
- sun
- the rays of the sun
- sunbeam
- a ray of sunlight
- sunburst
- a sudden emergence of the sun from behind clouds
- sunray
- a ray of artificial ultraviolet light from a sunray lamp
- sunrise
- atmospheric phenomena accompanying the daily appearance of the sun
- sunset
- atmospheric phenomena accompanying the daily disappearance of the sun
- superconductivity
- the disappearance of electrical resistance at very low temperatures
- supertwister
- the most powerful tornado which can create enormously devastating damage
- surface tension
- a phenomenon at the surface of a liquid caused by intermolecular forces
- sweat
- condensation of moisture on a cold surface
- sympathetic vibration
- (physics) vibration produced by resonance
- systemic circulation
- circulation that supplies blood to all the body except to the lungs
- systolic pressure
- the blood pressure (as measured by a sphygmomanometer) during the contraction of the left ventricle of the heart
- syzygy
- the straight line configuration of 3 celestial bodies (as the sun and earth and moon) in a gravitational system
- tailwind
- wind blowing in the same direction as the path of a ship or aircraft
- tempest
- (literary) a violent wind
- tension
- (physics) a stress that produces an elongation of an elastic physical body
- thaw
- warm weather following a freeze; snow and ice melt
- thermal
- rising current of warm air
- thermionic current
- an electric current produced between two electrodes as a result of electrons emitted by thermionic emission
- thermoelectricity
- electricity produced by heat (as in a thermocouple)
- theta rhythm
- the normal brainwave in the encephalogram of a person who is awake but relaxed and drowsy; occurs with low frequency and low amplitude
- thundershower
- a short rainstorm accompanied by thunder and lightning
- torchlight
- light from a torch or torches
- tornado
- a localized and violently destructive windstorm occurring over land characterized by a funnel-shaped cloud extending toward the ground
- torque
- a twisting force
- trade
- steady winds blowing from east to west above and below the equator
- tramontana
- a cold dry wind that blows south out of the mountains into Italy and the western Mediterranean
- transgression
- the spreading of the sea over land as evidenced by the deposition of marine strata over terrestrial strata
- transparence
- permitting the free passage of electromagnetic radiation
- trichroism
- pleochroism of a crystal so that it exhibits three different colors when viewed from three different directions
- turbulence
- unstable flow of a liquid or gas
- turbulent flow
- flow in which the velocity at any point varies erratically
- 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
- 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
- typhoon
- a tropical cyclone occurring in the western Pacific or Indian oceans
- ultrasound
- very high frequency sound; used in ultrasonography
- ultraviolet spectrum
- the spectrum of ultraviolet radiation
- updraft
- a strong upward air current
- UV
- radiation lying in the ultraviolet range; wave lengths shorter than light but longer than X rays
- valency
- the phenomenon of forming chemical bonds
- 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
- vapor 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)
- variation
- (astronomy) any perturbation of the mean motion or orbit of a planet or satellite (especially a perturbation of the earth's moon)
- venous pressure
- the pressure exerted on the walls of the veins by the circulating blood
- virga
- light wispy precipitation that evaporates before it reaches the ground (especially when the lower air is low in humidity)
- virtual image
- a reflected optical image (as seen in a plane mirror)
- vitelline circulation
- circulation of blood between the embryo and the yolk sac
- volcanism
- the phenomena associated with volcanic activity
- warm front
- the front of an advancing mass of warmer air
- waterpower
- the power to do work that is latent in a head of water
- waterspout
- a tornado passing over water and picking up a column of water and mist
- wave
- a persistent and widespread unusual weather condition (especially of unusual temperatures)
- wave front
- all the points just reached by a wave as it propagates
- 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
- west wind
- wind that blows from west to east
- whirlwind
- a more or less vertical column of air whirling around itself as it moves over the surface of the Earth
- 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
- whole gale
- wind moving 55-63 knots; 10 on the Beaufort scale
- wind
- a tendency or force that influences events
- wind generation
- power derived from the wind (as by windmills)
- windage
- the retarding force of air friction on a moving object
- windstorm
- a storm consisting of violent winds
- 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
- X-radiation
- electromagnetic radiation of short wavelength produced when high-speed electrons strike a solid target
- X-ray diffraction
- the scattering of X rays by the atoms of a crystal; the diffraction pattern shows structure of the crystal
- 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