WordVale

Science & Nature

100 words and expressions, each with a learner-friendly meaning. Tap any term for its page.

• photosynthesisthe process by which plants make food from sunlight
• mitosiscell division producing two identical daughter cells
• osmosisthe movement of water across a membrane toward higher solute
• entropya measure of disorder or randomness in a system
• catalysta substance that speeds up a reaction without being consumed
• isotopea form of an element with a different number of neutrons
• photona particle of light
• nucleusthe dense central core of an atom or a cell
• enzymea protein that speeds up biochemical reactions
• gravitythe force that attracts objects toward one another
• velocityspeed in a given direction
• momentumthe quantity of motion of a moving body
• frictionthe resistance when one surface moves over another
• inertiathe tendency of an object to resist changes in motion
• refractionthe bending of light as it passes between materials
• diffractionthe spreading of waves as they pass an obstacle or slit
• wavelengththe distance between successive peaks of a wave
• frequencythe number of wave cycles per unit of time
• conductionthe transfer of heat or electricity through a material
• convectionheat transfer by the movement of a fluid
• radiationenergy emitted as waves or particles
• valencethe combining capacity of an atom
• ionan atom with an electrical charge from losing or gaining electrons
• moleculetwo or more atoms bonded together
• compounda substance formed from two or more chemical elements
• solventa liquid in which other substances dissolve
• solutea substance dissolved in a solvent
• pHa scale measuring how acidic or basic a solution is
• oxidationa reaction in which a substance loses electrons
• combustiona chemical reaction with oxygen that releases heat and light
• ecosystema community of organisms interacting with their environment
• biodiversitythe variety of living things in a habitat
• habitatthe natural environment where an organism lives
• food chaina sequence showing what eats what in an ecosystem
• symbiosisa close, long-term interaction between two species
• parasitean organism that lives off a host, harming it
• predatoran animal that hunts others for food
• herbivorean animal that feeds on plants
• carnivorean animal that feeds on other animals
• omnivorean animal that eats both plants and animals
• photoperiodthe length of daily light that affects an organism
• germinationthe sprouting of a seed into a plant
• pollinationthe transfer of pollen enabling plants to reproduce
• adaptationa trait that helps an organism survive in its environment
• evolutionchange in inherited traits of populations over generations
• natural selectionthe survival of organisms best suited to their environment
• mutationa change in the genetic material of an organism
• genea unit of heredity that carries a trait
• chromosomea threadlike structure carrying genes
• DNAthe molecule that stores genetic instructions
• organisman individual living thing
• cellthe basic structural unit of living things
• membranea thin barrier controlling what enters and leaves a cell
• tissuea group of similar cells performing a function
• organa structure of tissues performing a specific function
• respirationthe release of energy from food within cells
• metabolismthe chemical processes that sustain life
• hormonea chemical messenger regulating body functions
• neurona cell that transmits nerve signals
• synapsethe junction where nerve signals pass between cells
• antibodya protein that identifies and neutralizes invaders
• pathogenan organism that causes disease
• bacteriasingle-celled microorganisms, some causing disease
• virusa tiny infectious agent that replicates inside host cells
• fungusan organism such as a mold, yeast, or mushroom
• planktontiny drifting organisms in oceans and lakes
• erosionthe wearing away of land by wind or water
• sedimentmaterial that settles at the bottom of a liquid
• tectonicrelating to the movement of the earth's crustal plates
• magmamolten rock beneath the earth's surface
• seismicrelating to earthquakes or vibrations of the earth
• geothermalrelating to heat from within the earth
• fossilthe preserved remains of a once-living organism
• stratalayers of rock or sediment
• atmospherethe layer of gases surrounding a planet
• ozonea gas layer that shields the earth from ultraviolet rays
• condensationthe change of a gas into a liquid
• evaporationthe change of a liquid into a gas
• precipitationwater falling as rain, snow, or hail
• humiditythe amount of water vapor in the air
• meteorologythe scientific study of weather
• equinoxa day when day and night are of equal length
• solsticethe day of the longest or shortest daylight
• orbitthe curved path of an object around a star or planet
• galaxya vast system of stars held together by gravity
• nebulaa cloud of gas and dust in space
• supernovathe explosive death of a massive star
• asteroida small rocky body orbiting the sun
• cometan icy body that releases gas and dust near the sun
• eclipsethe blocking of light when one body passes before another
• luminositythe total amount of light a star emits
• radioactivitythe emission of radiation from unstable atomic nuclei
• fissionsplitting an atomic nucleus to release energy
• fusioncombining atomic nuclei to release energy
• quantumthe smallest possible discrete unit of energy
• spectrumthe range of colors or wavelengths of light
• densitythe amount of mass in a given volume
• viscositya fluid's resistance to flowing
• buoyancythe upward force a fluid exerts on an object
• thermodynamicsthe study of heat, energy, and their transformations