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- natural phenomenon
all phenomena that are not artificial - levitation
the phenomenon of a person or thing rising into the air by apparently supernatural means - rebirth, metempsychosis
after death the soul begins a new cycle of existence in another human body - chemical phenomenon
any natural phenomenon involving chemistry (as changes to atoms or molecules) - allotropy, allotropism
the phenomenon of an element existing in two or more physical forms - exchange
chemical process in which one atom or ion or group changes places with another - photoconductivity, photoconduction
change in the electrical conductivity of a substance as a result of absorbing electromagnetic radiation - superconductivity
the disappearance of electrical resistance at very low temperatures - photochemical exchange
an exchange produced by the chemical action of radiant energy (especially light) - photoemission
an emission of photoelectrons (especially from a metallic surface) - crystallization, crystallisation, crystallizing
the formation of crystals - efflorescence, bloom
a powdery deposit on a surface - event, issue, effect, consequence, result, outcome, upshot
a phenomenon that follows and is caused by some previous phenomenon - aftereffect
any result that follows its cause after an interval - wake, aftermath, backwash
the consequences of an event (especially a catastrophic event) - bandwagon effect
the phenomenon of a popular trend attracting even greater popularity - brisance
the shattering or crushing effect of a sudden release of energy as in an explosion - 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 - by-product, byproduct
a secondary and sometimes unexpected consequence - change
the result of alteration or modification - coattails effect
(politics) the consequence of one popular candidate in an election drawing votes for other members of the same political party - 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 - dent
an appreciable consequence (especially a lessening) - 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) - harvest
the consequence of an effort or activity - impact, wallop
a forceful consequence - influence
the effect of one thing (or person) on another - perturbation
(physics) a secondary influence on a system that causes it to deviate slightly - variation
(astronomy) any perturbation of the mean motion or orbit of a planet or satellite (especially a perturbation of the earth's moon) - purchase
a means of exerting influence or gaining advantage - wind
a tendency or force that influences events - knock-on effect
a secondary or incidental effect - branch, offset, outgrowth, offshoot
a natural consequence of development - product
a consequence of someone's efforts or of a particular set of circumstances - placebo effect
any effect that seems to be a consequence of administering a placebo - position effect
(genetics) the effect on the expression of a gene that is produced by changing its location in a chromosome - reverberation, repercussion
a remote or indirect consequence of some action - response
a result - reaction
a response that reveals a person's feelings or attitude - side effect, fallout
any adverse and unwanted secondary effect - engine
something used to achieve a purpose - geological phenomenon
a natural phenomenon involving the structure or composition of the earth - endogeny
a geological phenomenon below the surface of the earth - chance, hazard, luck, fortune
an unknown and unpredictable phenomenon that causes an event to result one way rather than another - luck, fortune
an unknown and unpredictable phenomenon that leads to a favorable outcome - organic phenomenon
(biology) a natural phenomenon involving living plants and animals - physical phenomenon
a natural phenomenon involving the physical properties of matter and energy - distortion, aberration, optical aberration
an optical phenomenon resulting from the failure of a lens or mirror to produce a good image - abiogenesis, autogenesis, autogeny, spontaneous generation
a hypothetical organic phenomenon by which living organisms are created from nonliving matter - absorption band
a dark band in the spectrum of white light that has been transmitted through a substance that exhibits absorption at selective wavelengths - spectrum
an ordered array of the components of an emission or wave - absorption spectrum
the spectrum of electromagnetic radiation that has passed through a medium that absorbed radiation of certain wavelengths - actinic radiation, actinic ray
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, energy of activation
the energy that an atomic system must acquire before a process (such as an emission or reaction) can occur - aerodynamic force
forces acting on airfoils in motion relative to the air (or other gaseous fluids) - lift, aerodynamic lift
the component of the aerodynamic forces acting on an airfoil that opposes gravity - ground effect
apparent increase in aerodynamic lift experienced by an aircraft flying close to the ground - aerosol
a cloud of solid or liquid particles in a gas - affinity, chemical attraction
the force attracting atoms to each other and binding them together in a molecule - air hole, pocket, air pocket
a local region of low pressure or descending air that causes a plane to lose height suddenly - wash, race, backwash, slipstream, airstream
the flow of air that is driven backwards by an aircraft propeller - airstream
a relatively well-defined prevailing wind - alluvial fan, alluvial cone
a fan-shaped deposit where a fast flowing stream flattens out - alpha radiation, alpha ray
the radiation of alpha particles during radioactive decay - alpha rhythm, alpha wave
the normal brainwave in the electroencephalogram of a person who is awake but relaxed - alternating current, AC, alternating electric current
an electric current that reverses direction sinusoidally - alternation of generations, heterogenesis, xenogenesis
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 - metagenesis, digenesis
alternation of sexual and asexual generations - amperage
the strength of an electrical current measured in amperes - annual ring, growth ring
an annual formation of wood in plants as they grow - antitrades
wind in the upper atmosphere blowing above but in the opposite direction from the trade winds - motion, movement, apparent motion, apparent movement
an optical illusion of motion produced by viewing a rapid succession of still pictures of a moving object - acoustic phenomenon
a physical phenomenon associated with the production or transmission of sound - atmospheric phenomenon
a physical phenomenon associated with the atmosphere - atomic energy, nuclear energy
the energy released by a nuclear reaction - atomic power, nuclear 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 - attraction, attractive force
the force by which one object attracts another - affinity
(immunology) the attraction between an antigen and an antibody - repulsion, repulsive force
the force by which bodies repel one another - corona, aureole
the outermost region of the sun's atmosphere - aurora
an atmospheric phenomenon consisting of bands of light caused by charged solar particles following the earth's magnetic lines of force - aurora australis, southern lights
the aurora of the southern hemisphere - aurora borealis, northern lights
the aurora of the northern hemisphere - autofluorescence
self-induced fluorescence - bad luck, mishap, mischance
an unpredictable outcome that is unfortunate - irradiation, ray, shaft, beam, beam of light, light beam, ray of light, shaft of light
a column of light (as from a beacon) - ray, beam, electron beam
a group of nearly parallel lines of electromagnetic radiation - cathode ray
a beam of electrons emitted by the cathode of an electrical discharge tube - beta radiation, beta ray, electron radiation
radiation of beta particles during radioactive decay - beta rhythm, beta wave
the normal brainwave in the encephalogram of a person who is awake and alert - binding energy, separation energy
the energy required to separate particles from a molecule or atom or nucleus - bioelectricity
electric phenomena in animals or plants - bise, bize
a dry cold north wind in southeastern France - pressure, atmospheric pressure, air pressure
the pressure exerted by the atmosphere - black-body radiation, blackbody radiation
the electromagnetic radiation that would be radiated from an ideal black body - blood pressure
the pressure of the circulating blood against the walls of the blood vessels - systolic pressure
the blood pressure (as measured by a sphygmomanometer) during the contraction of the left ventricle of the heart - 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 - arterial pressure
the pressure of the circulating blood on the arteries - venous pressure
the pressure exerted on the walls of the veins by the circulating blood - boundary layer
the layer of slower flow of a fluid past a surface - brainwave, brain wave, cortical potential
(neurophysiology) rapid fluctuations of voltage between parts of the cerebral cortex that are detectable with an electroencephalograph - calm, calm air
wind moving at less than 1 knot - air, breeze, zephyr, gentle wind
a slight wind (usually refreshing) - sea breeze
a cooling breeze from the sea (during the daytime) - breath
a slight movement of the air - light air
wind moving 1-3 knots - light breeze
wind moving 4-7 knots - gentle breeze
wind moving 8-12 knots - moderate breeze
wind moving 13-18 knots - fresh breeze
wind moving 19-24 knots - strong breeze
wind moving 25-31 knots - Brownian movement, Brownian motion, pedesis
the random motion of small particles suspended in a gas or liquid - brush discharge
discharge between electrodes creating visible streamers of ionized particles - candlelight, candle flame
the light provided by a burning candle - capacity, capacitance, electrical capacity
an electrical phenomenon whereby an electric charge is stored - elastance, electrical elastance
the reciprocal of capacitance - capillarity, capillary action
a phenomenon associated with surface tension and resulting in the elevation or depression of liquids in capillaries - catastrophe, cataclysm
a sudden violent change in the earth's surface - nuclear winter
a long period of darkness and extreme cold that scientists predict would follow a full-scale nuclear war - continental drift
the gradual movement and formation of continents (as described by plate tectonics) - 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 - chaos
the formless and disordered state of matter before the creation of the cosmos - charge, electric charge
the quantity of unbalanced electricity in a body (either positive or negative) and construed as an excess or deficiency of electrons - 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 - pyroelectricity
generation of an electric charge on certain crystals (such as tourmaline) as a result of a change in temperature - positive charge
having a deficiency of electrons - negative charge
having a surplus of electrons - chatter mark
marks on a glaciated rock caused by the movement of a glacier - bond, chemical bond
an electrical force linking atoms - valency
the phenomenon of forming chemical bonds - cohesion
(physics) the intermolecular force that holds together the molecules in a solid or liquid - covalent bond
a chemical bond that involves sharing a pair of electrons between atoms in a molecule - cross-link, cross-linkage
a side bond that links two adjacent chains of atoms in a complex molecule - 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 - ionic bond, electrovalent bond, 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 - ionizing radiation
high-energy radiation capable of producing ionization in substances through which it passes - double bond
a covalent bond in which two pairs of electrons are shared between two atoms - coordinate bond, dative bond
a covalent bond in which both electrons are provided by one of the atoms - metallic bond
a chemical bond in which electrons are shared over many nuclei and electronic conduction occurs - peptide bond, peptide linkage
the primary linkage of all protein structures - chemical energy
that part of the energy in a substance that can be released by a chemical reaction - chinook, chinook wind, snow eater
a warm dry wind blowing down the eastern slopes of the Rockies - harmattan
a dusty wind from the Sahara that blows toward the western coast of Africa during the winter - chromatic aberration
an optical aberration in which the image has colored fringes - circulation
movement through a circuit - systemic circulation
circulation that supplies blood to all the body except to the lungs - pulmonary circulation
circulation of blood between the heart and the lungs - vitelline circulation
circulation of blood between the embryo and the yolk sac - cloud
any collection of particles (e.g., smoke or dust) or gases that is visible - cold wave
a wave of unusually cold weather - cold weather
a period of unusually cold weather - Coriolis force
(physics) a force due to the earth's rotation - freeze, frost
weather cold enough to cause freezing - corona
one or more circles of light seen around a luminous object - corona, corona discharge, corposant, St. Elmo's fire, 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 - cosmic background radiation, CBR, cosmic microwave background radiation, CMBR, cosmic microwave background, CMB
(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 - 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 - dust cloud
a cloud of dust suspended in the air - mushroom, mushroom cloud, mushroom-shaped cloud
a large cloud of rubble and dust shaped like a mushroom and rising into the sky after an explosion (especially of a nuclear bomb) - counterglow, gegenschein
a faint spot of light in the night sky that appears directly opposite the position of the sun - crosswind
wind blowing across the path of a ship or aircraft - fohn, foehn
a warm dry wind that blows down the northern slopes of the Alps - khamsin
an oppressively hot southerly wind from the Sahara that blows across Egypt in the spring - Santa Ana
a strong hot dry wind that blows in winter from the deserts of southern California toward the Pacific Coast - high wind
a very strong wind - headwind
wind blowing opposite to the path of a ship or aircraft - katabatic wind, catabatic wind
a wind caused by the downward motion of cold air - tailwind
wind blowing in the same direction as the path of a ship or aircraft - current, electric current
a flow of electricity through a conductor - cyclone
a violent rotating windstorm - cyclosis, streaming
the circulation of cytoplasm within a cell - daylight
light during the daytime - death
the permanent end of all life functions in an organism or part of an organism - decalescence
phenomenon that occurs when a metal is being heated and there is a sudden slowing in the rate of temperature increase - decomposition, decay
the organic phenomenon of rotting - dehiscence
(biology) release of material by splitting open of an organ or tissue - delta rhythm, delta wave
the normal brainwave in the encephalogram of a person in deep dreamless sleep - deposit, sedimentation, alluviation
the phenomenon of sediment or gravel accumulating - desquamation, peeling, shedding
loss of bits of outer skin by peeling or shedding or coming off in scales - exfoliation
the peeling off in flakes or scales of bark or dead skin - mother lode, champion lode
the main vein of ore in a deposit - load, lode
a deposit of valuable ore occurring within definite boundaries separating it from surrounding rocks - condensation, condensate
atmospheric moisture that has condensed because of cold - sweat
condensation of moisture on a cold surface - diapedesis
passage of blood cells (especially white blood cells) through intact capillary walls and into the surrounding tissue - dichroism
pleochroism of a crystal so that it exhibits two different colors when viewed from two different directions - diffraction
when light passes sharp edges or goes through narrow slits the rays are deflected and produce fringes of light and dark bands - DC, direct current, direct electric current
an electric current that flows in one direction steadily - signal
an electric quantity (voltage or current or field strength) whose modulation represents coded information about the source from which it comes - interrupt
a signal that temporarily stops the execution of a program so that another procedure can be carried out - doldrums
a belt of calms and light winds between the northern and southern trade winds of the Atlantic and Pacific