a physical phenomenon associated with the production or transmission of sound

a physical phenomenon associated with the atmosphere

the layer of slower flow of a fluid past a surface

the formless and disordered state of matter before the creation of the cosmos

any collection of particles (e.g., smoke or dust) or gases that is visible

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

a physical phenomenon involving electricity

a physical phenomenon associated with stationary or moving electrons and protons

any source of usable power

(physics) a thermodynamic quantity equivalent to the capacity of a physical system to do work; the units of energy are joules or ergs

(physics) the rate of doing work; measured in watts (= joules/second)

a phenomenon located at a single point in space-time; the fundamental observational entity in relativity theory

the space around a radiating body within which its electromagnetic oscillations can exert force on another similar body not in contact with it

(physics) the influence that produces a change in a physical quantity

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

an excited state of a stable particle causing a sharp maximum in the probability of absorption of electromagnetic radiation

a physical phenomenon associated with the equilibrium or motion of objects

the phenomenon of not permitting the passage of electromagnetic radiation

a physical phenomenon related to or involving light

the force applied to a unit area of surface; measured in pascals (SI unit) or in dynes (cgs unit)

the phenomenon of a propagating wave (light or sound) being thrown back from a surface

the change in direction of a propagating wave (light or sound) when passing from one medium to another

the ability of a microscope or telescope to measure the angular separation of images that are close together

(computer science) the number of pixels per square inch on a computer-generated display; the greater the resolution, the better the picture

the transmission of heat or electricity or sound

the movement of a wave through a medium

(physics) the transfer of energy between elementary particles or between an elementary particle and a field or between fields; mediated by gauge bosons

a phenomenon at the surface of a liquid caused by intermolecular forces

the straight line configuration of 3 celestial bodies (as the sun and earth and moon) in a gravitational system

permitting the free passage of electromagnetic radiation

unstable flow of a liquid or gas

the irregular motion of waves (usually caused by wind blowing in a direction opposite to the tide)

the phenomenon of floating (remaining on the surface of a liquid without sinking)

a stretch of turbulent water in a river or the sea caused by one current flowing into or across another current

a visible mass of water or ice particles suspended at a considerable altitude

(astronomy) the luminous cloud of particles surrounding the frozen nucleus of a comet; forms as the comet approaches the sun and is warmed

an immense cloud of gas (mainly hydrogen) and dust in interstellar space

an optical phenomenon resulting from the failure of a lens or mirror to produce a good image

a dark band in the spectrum of white light that has been transmitted through a substance that exhibits absorption at selective wavelengths

the energy that an atomic system must acquire before a process (such as an emission or reaction) can occur

forces acting on airfoils in motion relative to the air (or other gaseous fluids)

a cloud of solid or liquid particles in a gas

the force attracting atoms to each other and binding them together in a molecule

a local region of low pressure or descending air that causes a plane to lose height suddenly

energy derived from sources that do not use up natural resources or harm the environment

the strength of an electrical current measured in amperes

the energy released by a nuclear reaction

the force by which one object attracts another

the force by which bodies repel one another

an atmospheric phenomenon consisting of bands of light caused by charged solar particles following the earth's magnetic lines of force

the energy required to separate particles from a molecule or atom or nucleus; equals the mass defect

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

an electrical phenomenon whereby an electric charge is stored

the reciprocal of capacitance

a phenomenon associated with surface tension and resulting in the elevation or depression of liquids in capillaries

the outward force on a body moving in a curved path around another body

the inward force on a body moving in a curved path around another body

the quantity of unbalanced electricity in a body (either positive or negative) and construed as an excess or deficiency of electrons

generation of an electric charge on certain crystals (such as tourmaline) as a result of a change in temperature

(physics) the intermolecular force that holds together the molecules in a solid or liquid

that part of the energy in a substance that can be released by a chemical reaction

(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

clouds of particles or gases occurring throughout interstellar space

a cloud of dust suspended in the air

a large cloud of rubble and dust shaped like a mushroom and rising into the sky after an explosion (especially of a nuclear bomb)

a flow of electricity through a conductor

atmospheric moisture that has condensed because of cold

when light passes sharp edges or goes through narrow slits the rays are deflected and produce fringes of light and dark bands

a force that moves something along

the product of voltage and current

a field of force surrounding a charged particle

heating of an insulator by a high-frequency electric field

electricity produced by chemical action

energy made available by the flow of electric charge through a conductor

a definite stable energy that a physical system can have; used especially of the state of electrons in atoms or molecules

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

(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

am unwanted reflection in an optical system (or the fogging of an image that is caused by such a reflection)

one of the light or dark bands produced by the interference and diffraction of light

(meteorology) the atmospheric phenomenon created at the boundary between two different air masses

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

the layer of air near the earth is cooler than an overlying layer

a violent weather condition with winds 64-72 knots (11 on the Beaufort scale) and precipitation and thunder and lightning

a field of force surrounding a body of finite mass

a form of energy that is transferred by a difference in temperature

electricity produced by water power

the striking of a light beam on a surface

an electrical phenomenon whereby an electromotive force (EMF) is generated in a closed circuit by a change in the flow of current

(physics) the tendency of a body to maintain its state of rest or uniform motion unless acted upon by an external force

reciprocal reflection between two reflecting surfaces

the mechanical advantage gained by being in a position to use a lever

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

electrical discharges in the atmosphere

the lines of force surrounding a permanent magnet or a moving charged particle

a field that represents the energy lost from the radiator to space

the resonance absorption of a gamma ray by a nucleus identical to the nucleus that emitted the gamma ray

resonance of electrons or atoms or molecules or nuclei to radiation frequencies as a result of space quantization in a magnetic field

mechanical vibrations transmitted by an elastic medium

the path followed by an object moving through space

energy in a mechanical form

the sun visible at midnight (inside the Arctic or Antarctic Circles)

a turning force produced by an object acting at a distance (or a measure of that force)

a circle of light around the sun or moon

opacity to light

opacity to X-rays or other radiation

an optical phenomenon that results in a false or deceptive visual impression

electricity generated by light or affected by light

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

the phenomenon of different colors appearing when certain crystals are viewed from different directions

the phenomenon in which waves of light or other radiation are restricted in direction of vibration

the difference in electrical charge between two points in a circuit expressed in volts

the pressure exerted by a gas

the pressure exerted by a fluid

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

pressure exerted by the fluids inside the eyeball; regulated by resistance to the outward flow of aqueous humor

pressure that keeps oil on the moving parts of an internal-combustion engine

(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

the minute pressure exerted on a surface normal to the direction of propagation of a wave

the difference between the instantaneous pressure at a point in a sound field and the average pressure at that point

a propelling force

the force used in pulling

the force used in pushing

(mechanics) the equal and opposite force that is produced when any force is applied to a body

energy that is transmitted in the form of (electromagnetic) radiation; energy that exists in the absence of matter

energy that is radiated or transmitted in the form of rays or waves or particles

splitting a ray into two parallel rays polarized perpendicularly

any mechanical force that tends to retard or oppose motion

a material's capacity to conduct electricity; measured as the reciprocal of electrical resistance

a material's opposition to the flow of electric current; measured in ohms

opposition to the flow of electric current resulting from inductance and capacitance (rather than resistance)

(physics) opposition to magnetic flux (analogous to electric resistance)

a transient shower of meteors when a meteor swarm enters the earth's atmosphere

the tendency of high-frequency alternating current to distribute near the surface of a conductor

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)

the acoustic phenomenon that gives sound a penetrating quality

the passage of electricity through a conductor

change in the apparent frequency of a wave as observer and source move toward or away from each other

(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

all the points just reached by a wave as it propagates

electrical signals produced by unwanted sources (atmospherics or receiver noise or unwanted transmitters)

electricity produced by friction

a flow of electric charge

electricity produced by heat (as in a thermocouple)

(physics) force that produces strain on a physical body

an interaction between charged elementary particles that is intermediate in strength between the strong and weak interactions; mediated by photons

a weak interaction between particles that results from their mass; mediated by gravitons

(physics) the interaction that binds protons and neutrons together in the nuclei of atoms; mediated by gluons

(physics) an interaction between elementary particles involving neutrinos or antineutrinos that is responsible for certain kinds of radioactive decay; mediated by intermediate vector bosons

a force over an area produced by a pressure difference

atmospheric phenomena accompanying the daily appearance of the sun

atmospheric phenomena accompanying the daily disappearance of the sun

a glow sometimes seen in the sky after sunset

surface tension at the surface separating two non-miscible liquids

a twisting force

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)

a reflected optical image (as seen in a plane mirror)

the rate at which energy is drawn from a source that produces a flow of electricity in a circuit; expressed in volts

the force that produces magnetic flux

(biology) a hypothetical force (not physical or chemical) once thought by Henri Bergson to cause the evolution and development of organisms

the power to do work that is latent in a head of water

the atmospheric conditions that comprise the state of the atmosphere in terms of temperature and wind and clouds and precipitation

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

the apparent displacement of an object as seen from two different points that are not on a line with the object

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