types:
acoustic phenomenon
a physical phenomenon associated with the production or transmission of sound
chaos
the formless and disordered state of matter before the creation of the cosmos
cloud
any collection of particles (e.g., smoke or dust) or gases that is visible
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
electricity
a physical phenomenon associated with stationary or moving electrons and protons
energy
any source of usable power
energy,
free energy
(physics) a thermodynamic quantity equivalent to the capacity of a physical system to do work; the units of energy are joules or ergs
power
(physics) the rate of doing work; measured in watts (= joules/second)
event
a phenomenon located at a single point in space-time; the fundamental observational entity in relativity theory
field,
field of force,
force field
the space around a radiating body within which its electromagnetic oscillations can exert force on another similar body not in contact with it
force
(physics) the influence that produces a change in a physical quantity
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
resonance
an excited state of a stable particle causing a sharp maximum in the probability of absorption of electromagnetic radiation
opacity
the phenomenon of not permitting the passage of electromagnetic radiation
reflection,
reflexion
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
resolution,
resolving power
the ability of a microscope or telescope to measure the angular separation of images that are close together
resolution
(computer science) the number of pixels per square inch on a computer-generated display; the greater the resolution, the better the picture
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
surface tension
a phenomenon at the surface of a liquid caused by intermolecular forces
syzygy
the straight line configuration of 3 celestial bodies (as the sun and earth and moon) in a gravitational system
chop
the irregular motion of waves (usually caused by wind blowing in a direction opposite to the tide)
floatation,
flotation
the phenomenon of floating (remaining on the surface of a liquid without sinking)
cloud
a visible mass of water or ice particles suspended at a considerable altitude
coma
(astronomy) the luminous cloud of particles surrounding the frozen nucleus of a comet; forms as the comet approaches the sun and is warmed
nebula
an immense cloud of gas (mainly hydrogen) and dust in interstellar space
absorption band
a dark band in the spectrum of white light that has been transmitted through a substance that exhibits absorption at selective wavelengths
aerodynamic force
forces acting on airfoils in motion relative to the air (or other gaseous fluids)
aerosol
a cloud of solid or liquid particles in a gas
air hole,
air pocket,
pocket
a local region of low pressure or descending air that causes a plane to lose height suddenly
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
aurora
an atmospheric phenomenon consisting of bands of light caused by charged solar particles following the earth's magnetic lines of force
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
capillarity,
capillary action
a phenomenon associated with surface tension and resulting in the elevation or depression of liquids in capillaries
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
charge,
electric charge
the quantity of unbalanced electricity in a body (either positive or negative) and construed as an excess or deficiency of electrons
pyroelectricity
generation of an electric charge on certain crystals (such as tourmaline) as a result of a change in temperature
cohesion
(physics) the intermolecular force that holds together the molecules in a solid or liquid
chemical energy
that part of the energy in a substance that can be released by a chemical reaction
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
cosmic dust
clouds of particles or gases occurring throughout interstellar space
diffraction
when light passes sharp edges or goes through narrow slits the rays are deflected and produce fringes of light and dark bands
galvanism
electricity produced by chemical action
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
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
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
flare
an unwanted reflection in an optical system (or the fogging of an image that is caused by such a reflection)
front
(meteorology) the atmospheric phenomenon created at the boundary between two different air masses
greenhouse effect,
greenhouse warming
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
inversion
the layer of air near the earth is cooler than an overlying layer
storm,
violent storm
a violent weather condition with winds 64-72 knots (11 on the Beaufort scale) and precipitation and thunder and lightning
heat,
heat energy
a form of energy that is transferred by a difference in temperature
incidence
the striking of a light beam on a surface
inductance,
induction
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
leverage,
purchase
the mechanical advantage gained by being in a position to use a lever
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
radiation field
a field that represents the energy lost from the radiator to space
nuclear resonance
the resonance absorption of a gamma ray by a nucleus identical to the nucleus that emitted the gamma ray
magnetic resonance
resonance of electrons or atoms or molecules or nuclei to radiation frequencies as a result of space quantization in a magnetic field
sound
mechanical vibrations transmitted by an elastic medium
midnight sun
the sun visible at midnight (inside the Arctic or Antarctic Circles)
moment
a turning force produced by an object acting at a distance (or a measure of that force)
halo
a circle of light around the sun or moon
optical illusion
an optical phenomenon that results in a false or deceptive visual impression
piezo effect,
piezoelectric effect,
piezoelectricity
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
pleochroism
the phenomenon of different colors appearing when certain crystals are viewed from different directions
polarisation,
polarization
the phenomenon in which waves of light or other radiation are restricted in direction of vibration
head
the pressure exerted by a fluid
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
IOP,
intraocular pressure
pressure exerted by the fluids inside the eyeball; regulated by resistance to the outward flow of aqueous humor
oil pressure
pressure that keeps oil on the moving parts of an internal-combustion engine
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
pull
the force used in pulling
reaction
(mechanics) the equal and opposite force that is produced when any force is applied to a body
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
resistance
any mechanical force that tends to retard or oppose motion
conductance
a material's capacity to conduct electricity; measured as the reciprocal of electrical resistance
reactance
opposition to the flow of electric current resulting from inductance and capacitance (rather than resistance)
reluctance
(physics) opposition to magnetic flux (analogous to electric resistance)
skin effect
the tendency of high-frequency alternating current to distribute near the surface of a conductor
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)
red shift,
redshift
(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
wave front
all the points just reached by a wave as it propagates
electrical disturbance
electrical signals produced by unwanted sources (atmospherics or receiver noise or unwanted transmitters)
stress
(physics) force that produces strain on a physical body
electromagnetic interaction
an interaction between charged elementary particles that is intermediate in strength between the strong and weak interactions; mediated by photons
weak force,
weak interaction
(physics) an interaction between elementary particles involving neutrinos or antineutrinos that is responsible for certain kinds of radioactive decay; mediated by intermediate vector bosons
suction
a force over an area produced by a pressure difference
sunrise
atmospheric phenomena accompanying the daily appearance of the sun
sunset
atmospheric phenomena accompanying the daily disappearance of the sun
afterglow
a glow sometimes seen in the sky after sunset
vapor pressure,
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)
virtual image
a reflected optical image (as seen in a plane mirror)
electromotive force,
emf,
voltage
the rate at which energy is drawn from a source that produces a flow of electricity in a circuit; expressed in volts
waterpower
the power to do work that is latent in a head of water
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
parallax
the apparent displacement of an object as seen from two different points that are not on a line with the object
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