OGT Vocabulary and K-12 Science Glossary  

   A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Home

A

abiotic

Non-living.

 

acceleration

The rate of change a with respect to time.

 

acid

A substance that dissolves in water with the formation of hydrogen ions and reacts with a base to form a salt and water. It neutralizes alkalis, dissolves some metals, and turns litmus red; typically, a corrosive and sour-tasting liquid.

 

adaptation

Adjustment to environmental conditions, modification of an organism or its parts that makes it more fit for existence under the conditions of its environment.

 

alleles

Any of the alternative forms of a gene that may occur at a given locus on a chromosome.

 

anemometer

An instrument for measuring and indicating the force or speed of the wind.

 

asexual

reproduction

Involving or reproducing by reproductive processes (as cell division, spore formation, fission or budding) that do not involve the union of germ cells or egg and sperm.

 

asteroid

A small rocky body orbiting the sun.

 

atmosphere

The gaseous envelope surrounding the earth; consists of oxygen, nitrogen and other gases, extends to a height of about 40,744 km (22,000 miles), and rotates with Earth.

 

atmospheric

pressure

The pressure exerted by the atmosphere at the surface of the Earth due to the weight of the air.

 

atom

The smallest particle of an element that can exist either alone or in combination.

 

atomic number

The number of protons in the nucleus of an atom.

 Top A B C D E F G  H I J K L M N O P Q R S T U V W X Y Z

B

bacteria

Unicellular, prokaryotic microorganisms that lack chlorophyll, multiply by fission, and can be seen only with a microscope; they occur in three main forms: spherical, rod-shaped and spiral. Some bacteria cause diseases such as pneumonia, tuberculosis and anthrax, and others are necessary for fermentation and nitrogen fixation.

 

balance

An instrument for measuring mass.

 

barometer

An instrument for determining the pressure of the atmosphere.

 

base

A substance that dissolves in water with the formation of hydroxyl ions and reacts with an acid to form a salt and water; turns litmus paper blue.

 

biogeochemical

cycles

Relating to the partitioning and cycling of chemical elements and compounds between the living and nonliving parts of an ecosystem.

 

biological

evolution

 

Changes in the genetic composition of a population through successive generations.

biomass

The amount of living matter.

 

biome

Major ecological community (tropical rain forest, grassland or desert).

 

biotechnology

Biological science when applied especially in genetic engineering and recombinant DNA technology.

 

biotic

Relating to life.

 

body covering

Feature that covers the body, such as fur or feathers.

 

body system

A system of the body (i.e. digestive system, circulatory system).

 

boiling point

The temperature at which a liquid boils.

 Top A B C D E F G  H I J K L M N O P Q R S T U V W X Y Z

C

capacity

The maximum amount or number that can be contained or accommodated.

 

carnivore

A flesh-eating animal.

 

cell

The smallest structural and functional unit of an organism.

 

cell division

The formation of two daughter cells from one parent cell, mitosis.

 

cell membrane

The bounding membrane of cells which controls the entry of molecules and the interaction of cells with their environment, plasma membrane.

 

cell respiration

Metabolic processes which break down nutrients into usable energy.

 

cell wall

A structure external to the plasma membrane of a plant cell. It provides structure and support.

 

characteristic

A distinguishing trait, feature, quality or property.

 

chemical change

A change in a substance resulting in an entirely different substance with different

properties from the first.

 

chemical

property

Chemical characteristics of a substance that distinguish it from other substances.

 

 

chemical

reaction

A process that involves rearrangement of the molecular or ionic structure of a substance, as opposed to a change in physical form or a nuclear reaction.

 

chemosynthesis

Synthesis of organic compounds (as in living cells) by energy derived from chemical reactions.

 

chloroplast

A plastid that contains chlorophyll and is the site of photosynthesis.

 

chromosome

A threadlike structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes.

 

chrysalis

The pupa of a butterfly and some insects.

 

cilia

Fine hair-like protrusions of the cell surface, which beat in unison to create currents of liquid over cell surface or propel the cell through the medium.

circuit

The complete path of an electric current usually including the source of electric

energy.

 

circular motion

Motion of an object that follows the circumference of a circle.

 

classification

Systematic arrangement in groups or categories according to established criteria.

 

climate

The average course or condition of the weather at a place usually over a period

of years as exhibited by temperature, wind velocity and precipitation.

 

comet

A celestial body that consists of a fuzzy head usually surrounding a bright nucleus, that has a usually highly eccentric orbit, and that often, when in the part of its orbit near the sun, develops a long tail which points away from the sun.

 

community

Interacting populations that live in a defined habitat.

 

composition

The qualitative and quantitative makeup of a chemical compound.

 

compound

A substance formed from two or more elements chemically united in fixed proportions.

 

condensation

The conversion of a substance (such as water) from the vapor state to a denser liquid or solid state usually initiated by a reduction in the temperature of the vapor.

 

conduction

Process by which heat or electricity is transmitted through a material or body without movement of the medium itself.

 

conservation

A careful preservation and protection of something; especially planned management of a natural resource to prevent exploitation, destruction or neglect.

 

consumer

An organism requiring complex organic compounds for food, which it obtains by

preying on other organisms or by eating particles of organic matter.

 

control

A group used as a standard of comparison for checking the results of an experiment.

 

covalent

Chemical bonds formed by the sharing of electrons between atoms.

 

convection

The circulatory motion that occurs in a fluid at a non-uniform temperature owing to the variation of its density and the action of gravity.

convergent

To come together or tend to come together at a point.

 

core

The central part of a celestial body (as Earth or sun) usually having different physical properties from the surrounding parts.

 

crust

The outer part of a planet, moon or asteroid composed essentially of crystalline

rocks.

 

crustal deformation

A change in the crust of a planet, moon or asteroid.

 

current

Continuous flow as of air, water or electric charge.

 

cycle

An interval of time during which a sequence of a recurring succession of events or phenomena is completed.

 Top A B C D E F G  H I J K L M N O P Q R S T U V W X Y Z

D

decay rate

The rate at which a radioactive isotope disintegrates until a final non-radioactive isotope is formed.

 

decomposers

Organisms such as bacteria and fungi that feed and breakdown dead organisms returning constituents of organic substances to the environment.

 

dependent

variable

 

A variable whose values are determined by one or more (independent) variables.

 

design

To create, fashion, execute or construct according to plan.

 

differentiation

The sum of the processes whereby apparently indifferent cells, tissues and structures attain their adult form and function.

 

diversity

A great deal of variety.

 

DNA

Deoxyribonucleic acid, a double strand of nucleotides, that is a self-replicating material present in living organisms as the main constituent of chromosomes. It contains the genetic code and transmits the heredity pattern.

 

dominant

A gene, that when present, is expressed in the phenotype.

 Top A B C D E F G  H I J K L M N O P Q R S T U V W X Y Z

 E

eclipse

The total or partial obscuring of one celestial body by another.

 

ecological

The interactions and relationships between organisms and their environment.

 

ecosystem

The complex of a community of organisms and its environment functioning as an ecological unit.

 

egg

Female gamete; ovum.

 

electric field

A region associated with a distribution of electric charge or a varying magnetic field, in which forces due to that charge or field, act upon other electric charges.

 

electric force

A force that exists between two charged objects.

 

electricity

A form of energy resulting from the existence of charged particles, either statically as an accumulation of charge or dynamically as a current.

 

electromagnetic

radiation

A kind of radiation including visible light, radio waves, gamma rays and x-rays in which electric and magnetic fields vary simultaneously.

 

electromagnetic

spectrum

The entire range of wavelengths or frequencies of electromagnetic radiation extending from gamma rays to the longest radio waves and including visible light.

 

 

electron

A stable subatomic particle with negative electrical charge, found in all atoms and acting as the primary carrier of electricity in solids.

element

Any of more than 100 fundamental substances that consist of atoms of only one kind and that singly or in combination constitute all matter.

 

emigration

A category of population dispersal covering one-way movement out of the population area.

 

endothermic

Characterized by or formed with absorption of heat.

 

energy

The capacity for doing work, can be in various forms such as nuclear, sound, thermal and light.

 

entropy

A thermodynamic quantity representing the unavailability of a system's thermal energy for conversion into mechanical work, often interpreted as the degree of disorder or randomness in the system.

 

environment

The complex of physical, chemical and biotic factors that act upon an organism or an ecological community and ultimately determine its form and survival.

 

epicenter

The part of the Earth's surface directly above the focus of an earthquake.

 

equilibrium

A state in which opposing forces or influences are balanced.

 

eukaryotic

An organism composed of one or more cells containing visibly evident nuclei and organelles.

 

evaporation

To convert into vapor.

 

evidence

Facts or observations on which a conclusion can be based.

 

evolution

(biological)

 

Changes in the genetic composition of a population through successive generations.

 

exothermic

Characterized by or formed with liberation of heat.

 

extinct

A species of organisms that no longer exists.

 Top A B C D E F G  H I J K L M N O P Q R S T U V W X Y Z

F

faulting

To fracture so as to produce a geologic fault.

 

fermentation

An enzymatically controlled anaerobic breakdown of an energy-rich compound.

 

fission

The splitting of an atomic nucleus resulting in the release of large amounts of energy.

 

flagella

Long hair-like extensions from the cell surface whose movement is used for locomotion.

 

focus

The place of origin of an earthquake or moonquake (as related to earthquakes).

 

folding

Causing rock strata to undergo bending or curvature.

 


food chain

An arrangement of the organisms of an ecological community according to the order of predation in which each uses the next usually lower member as a food source.

 

food web

The totality of interacting food chains in an ecological community; interacting food chains in an ecological community.

 

force

An influence, that if applied to a free body, results chiefly in an acceleration of that body in the direction of its application.

 

fossil

Remnant, impression or trace of an organism of past geologic ages that has been preserved in the Earth's crust.

 

fossil fuel

A fuel (such as coal, oil or natural gas) that is formed in Earth from plant or animal remains.

 

frame of

reference

An arbitrary set of axes with reference to which the position or motion of something is described or physical laws are formulated.

 

friction

The force that resists relative motion between two bodies in contact.

 

fungi

Any of a major group of saprophytic and parasitic spore-producing organisms including molds, rusts, mildews, smuts, mushrooms and yeasts.

 

fusion

The union of atomic nuclei to form heavier nuclei resulting in the release of enormous quantities of energy.

 Top A B C D E F G  H I J K L M N O P Q R S T U V W X Y Z

G

galaxy

Any of the very large groups of stars and associated matter that are found throughout the universe.

 

gas

A fluid (such as air) that has neither independent shape nor volume but tends to expand indefinitely.

 

gene

A functional hereditary unit located at a particular point on a chromosome that controls or acts in the transmission of hereditary characteristics.

 

genetic drift

The process by which gene frequencies are changed.

 

germination

The beginning of growth in a spore, seed, zygote etc., especially following a dormant period.

 

glaciation

To subject to glacial action in which a large body of ice moves slowly down a slope or valley, or spreads outward on a land surface.

 

gravitation

A force manifested by acceleration toward each other of two free material particles or bodies, or of radiant-energy quanta.

 

gravity

The gravitational attraction of the mass of the Earth, the moon or a planet for

bodies at or near its surface.

Top A B C D E F G  H I J K L M N O P Q R S T U V W X Y Z

H

habitability

Suitable for a dwelling place.

 

habitat

The place or environment where a plant or animal naturally or normally lives and grows.

herbivore

A plant-eating animal.

 

heredity

The sum of the qualities and potentialities genetically derived from one's ancestors; the relation between successive generations, by which characteristics persist.

 

heritable

Capable of being inherited or of passing by inheritance.

 

homeostasis

A state of equilibrium between different but interrelated functions or elements, as in an organism or group.

 

humidity

The amount of moisture in the atmosphere.

 

hydrosphere

The aqueous envelope of the Earth including bodies of water and aqueous vapor in the atmosphere.

 

hypothesis

A formula derived by inference from scientific data that explains a principle operating in nature.

Top A B C D E F G  H I J K L M N O P Q R S T U V W X Y Z

I

igneous

Relating to, resulting from, or suggestive of the intrusion or extrusion of magma or volcanic activity.

 

immigration

Coming into the population.

 

independent

assortment

 

Each chromosome in a pair that is independent of other chromosomes.

 

independent

variable

A variable whose value is specified first and determines the value of one or more other values.

 

infrared

radiation

Invisible rays just beyond the red end of the visible spectrum. Their waves are longer than those of the spectrum colors but shorter than radio waves, and have a penetrating heating effect; used in cooking and photography.

 

interstellar

Located, taking place or traveling among the stars, especially of the Milky Way galaxy.

 

ion

An atom or group of atoms that carries a positive or negative electric charge as a result of having lost or gained one or more electrons.

 

isotope

Any of two or more species of atoms of a chemical element with the same atomic number and nearly identical chemical behavior, but with differing atomic mass or mass number and different physical properties.

 Top A B C D E F G  H I J K L M N O P Q R S T U V W X Y Z

J

jumping genes

Genes that move from one position on the chromosome to another.

 

 Top A B C D E F G  H I J K L M N O P Q R S T U V W X Y Z

K

kinetic energy

Energy associated with motion.

 

Top A B C D E F G  H I J K L M N O P Q R S T U V W X Y Z 

L

landform

A natural feature of a land surface.

 

life

An organism that has the capacity for metabolism, growth, reaction to stimuli and reproduction.

 

life cycle

The series of stages in form and functional activity through which an organism passes from fertilized ovum to the fertilized ovum of the next generation.

 

liquid

A fluid (such as water) that has no independent shape but has a definite volume, does not expand indefinitely and that is only slightly compressible.

 

lithosphere

The solid part of a celestial body (such as Earth), specifically, the outer part of the solid Earth composed of rock essentially like that exposed at the surface and usually considered to be about 80 kilometers (50 miles) in thickness.

Top A B C D E F G  H I J K L M N O P Q R S T U V W X Y Z 

M

magma

Molten rock material within the Earth from which igneous rock results by cooling.

 

magnetic

reversal

Periods of time in which there was a reversal in direction of the Earth's magnetic field.

 

mantle

The part of the interior of a terrestrial planet, especially the Earth, that lies beneath the lithosphere and above the central core.

 

mass

The property of a body that is a measure of its inertia and that is commonly taken as a measure of the amount of material it contains causing it to have weight in a gravitational field.

 

matter

Material substance that occupies space, has mass and is composed of atoms consisting of protons, neutrons and electrons that constitutes the observable universe, and that is interchangeable with energy.

 

mean

The sum of a set of numbers divided by the number of elements in the set.

 

median

The middle number or item in a set of numbers or objects arranged from least to greatest, or the mean of the two middle numbers when the set has two middle numbers.

 

metamorphism

A change in the constitution of rock; specifically, a pronounced change affected by pressure, heat and water that results in a more compact and more highly crystalline condition.

 

meteor

Any of the small particles of matter in the solar system that are directly observable only by their incandescence from frictional heating on entry into the atmosphere.

 

meteoroid

One of a large number of celestial bodies of various size that appear as meteors when they enter Earth's atmosphere.

method

A systematic procedure, technique or mode of inquiry employed by or proper to a particular discipline or art.

 

microorganisms

An organism of microscopic or ultramicroscopic size.

 

metric system

A decimal system of weights and measures based on the meter and on the kilogram.

 

Milky Way

A broad luminous irregular band of light that stretches completely around the celestial sphere and is caused by the light of myriads of faint stars.

 

mineral

A solid homogeneous crystalline chemical element or compound that results from the inorganic processes of nature.

 

mitochondria

Cell structure responsible for cellular respiration.

 

mixture

A portion of matter consisting of two or more components in varying proportions that retain their own properties.

 

mode

The number or object that appears most frequently in a set of numbers of objects.

 

model

A description or analogy used to help visualize something (such as an atom) that cannot be directly observed.

 

molecule

The smallest particle of a substance that retains all the properties of the substance and is composed of one or more atoms.

 

moon cycle

The cycle of the moon's phases, from new to full and back.

 

motion

An act, process or instance of changing position through time.

 

multicellular

Having or consisting of many cells.

 

mutation

A relatively permanent change in hereditary material involving either a physical

change in chromosome relations or a biochemical change in the codon(s) that make up genes.

Top A B C D E F G  H I J K L M N O P Q R S T U V W X Y Z

N

natural

Existing in, or produced by nature.

 

natural selection

The principle that in a given environment individuals having characteristics that aid survival will produce more offspring, and the proportion of individuals having such characteristics will increase with each succeeding generation.

 

nesting

To build or occupy a nest; settle in.

 

neutral

Neither acidic nor basic (as in pH).

neutrons

An uncharged elementary particle that has a mass nearly equal to that of the proton and is present in atomic nuclei.

 

nuclear

Used in or produced by a nuclear reaction; referring to particles or properties of an atomic nucleus.

 

 

nuclear reaction

A change in the identity or characteristics of an atomic nucleus that results when it is bombarded with an energetic particle.

 

nucleus

1. The positively charged central portion of an atom that comprises nearly all of the atomic mass and that consists of protons and neutrons. 2. The portion of a eukoryotic cell that is surrounded by a nuclear membrane and contains DNA.

 

nutrient

A nutritive substance or ingredient.

 

Top A B C D E F G  H I J K L M N O P Q R S T U V W X Y Z

O

observe

To watch carefully, especially with attention to details or behavior for the purpose of arriving at a judgment.

 

ocean trench

A long, narrow, deep depression in the ocean bed.

 

omnivore

An animal that feeds on both animal and vegetable substances.

 

orbit

A path described by one body in its revolution about another (as by the Earth about the sun or by an electron about an atomic nucleus).

 

organ

A differentiated structure (such as a heart, kidney, leaf or stem) consisting of cells and tissues, and performing some specific function in an organism.

 

organ systems

Organs working together for a specific function.

 

organic

Compounds containing carbon and chiefly or ultimately of biological origin.

 

organism

An individual constituted to carry on the activities of life by means of organs separate in function but mutually dependent; a living being.

 

oxidation

Combination of a substance with oxygen.

 

oxidize

To combine with oxygen.

Top A B C D E F G  H I J K L M N O P Q R S T U V W X Y Z

P

parasite

An organism living in, with or on another organism in which a parasite obtains benefits from a host that it usually injures.

 

particle

Any of the basic units of matter and energy (such as a molecule, atom, proton, electron or photon).

 

pattern

A reliable sample of traits, acts, tendencies or other observable characteristics.

 

periodic table

An arrangement of chemical elements based on the periodic law.

 

pH scale

A numerical measure of the acidity or alkalinity of a chemical solution.

 

 

 

phenomenon

A fact or event of scientific interest susceptible to scientific description and explanation.

 

photosynthesis

The chemical process by which chlorophyll-containing plants use light to convert carbon dioxide and water into carbohydrates, releasing oxygen as a byproduct.

 

physical change

 

A change in a substance that does not alter its chemical makeup.

 

physical

properties

A property of a material that can be observed without changing the chemical makeup of the material.

 

physiology

The biological science of essential and characteristic life processes, activities and functions.

 

pitch

The property of a sound, especially a musical tone, that is determined by the frequency of the waves producing it; highness or lowness of sound.

 

planet

Any of the large bodies that revolve around the sun in the solar system.

 

pollution

A substance that, when added to the environment causes the environment to be harmful or unfit for living things.

 

population

All the plants or animals of the same kind found in a given area.

 

potential energy

The energy that matter has because of its position or because of the arrangement of atoms or parts.

 

precipitation

A deposit on Earth of hail, mist, rain, sleet or snow.

 

predator

An animal that lives by capturing prey as a means of maintaining life.

 

prey

An animal taken by a predator as food.

 

producer

Any of various organisms (such as a green plant) which produce their own organic compounds from simple precursors (such as carbon dioxide and inorganic nitrogen) and many of which are food sources for other organisms.

 

prokaryotic

A cellular organism (such as a bacterium or a blue-green alga) that does not have a distinct nucleus.

 

property

A quality or trait belonging to an individual or thing.

 

proton

A stable subatomic particle occurring in all atomic nuclei with a positive electric charge equal in magnitude to that of an electron.

Top A B C D E F G  H I J K L M N O P Q R S T U V W X Y Z

Q

qualitative

Involving quality or kind.

 

quantitative

Involving the measurement of quantity or amount.

 

Top A B C D E F G  H I J K L M N O P Q R S T U V W X Y Z

R

radiation

The transfer of heat by radiation (such as energy transfer). The process of emitting radiant energy in the form of waves or particles (such as particle emission).

 

react

To undergo chemical reaction (chemically).

 

reactant

A substance that enters into and is altered in the course of a chemical reaction.

 

recycle

To process (as liquid body waste, glass or cans) in order to regain material for human use.

 

reference point

A basis or standard for evaluation, assessment or comparison; a criterion.

 

reflection

The throwing back by a body or surface of light, heat or sound without absorbing it.

 

refraction

Deflection from a straight path undergone by a light ray or energy wave in passing obliquely from one medium (such as air) into another (such as glass) in which its velocity is different.

 

repel

To force away or apart, or tend to do so by mutual action at a distance.

 

replicate

To duplicate experiments, procedures or samples.

 

reproduction

The process by which organisms give rise to offspring and which fundamentally consists of the segregation of a portion of the parental body by a sexual or an asexual process, and its subsequent growth and differentiation into a new individual.

 

resource

Industrial materials and capacities (as mineral deposits and waterpower) supplied by nature (earth science) and substances used by an organism for survival (biology).

 

respiration

The physical and chemical processes by which an organism supplies its cells and tissues with the oxygen needed for metabolism and relieves them of the carbon dioxide formed in energy-producing reactions.

 

rotation

The turning of a body part about its long axis as if on a pivot.

Top A B C D E F G  H I J K L M N O P Q R S T U V W X Y Z

S

scavenger

An organism that feeds habitually on refuse or carrion.

 

scientific law

A statement of an order or relation of phenomena that, so far as is known, is invariable under the given conditions.

 

scientific

method

Principles and procedures for the systematic pursuit of knowledge involving the

recognition and formulation of a problem, the collection of data through observation and experiment, and the formulation and testing of hypotheses.

 

scientific theory

A plausible or scientifically acceptable general principle or body of principles offered to explain phenomena.

 

sediment

Material deposited by water, wind or glaciers.

 

 

segregation

The separation of two alleles in a heterozygote when gametes are formed.

 

significant

figure

Each of the digits of a number that are used to express it to the required degree of accuracy.

 

solid

A substance that does not flow perceptibly under moderate stress, has a definite capacity for resisting forces (such as compression or tension) that tend to deform it, and under ordinary conditions retains a definite size and shape.

 

solubility

The amount of a substance that will dissolve in a given amount of another substance.

 

solution

An act, or the process by which a solid, liquid or gaseous substance is homogeneously mixed with a liquid or sometimes a gas or solid.

 

sound waves

Mechanical radiant energy that is transmitted by longitudinal pressure waves in a material medium (such as air) and is the objective cause of hearing.

 

species

A group of organisms consisting of similar individuals capable of exchanging genes or interbreeding.

 

sperm

A male gamete.

 

star

A natural luminous body visible in the sky, especially at night.

 

structure

The arrangement of particles or parts in a substance or body.

 

survival

The continuation of life or existence.

 

system

1. A group of body organs that together perform one or more vital functions. 2. An organized group of devices, parts or factors that together perform a function or drive a process (weather systems, mechanical systems).

Top A B C D E F G  H I J K L M N O P Q R S T U V W X Y Z

T

technology

Human innovation in action that involves the generation of knowledge and processes to develop systems that solve problems and extend human capabilities. The innovation, change, or modification of the natural environment to satisfy perceived human needs and wants.

 

theory

A supposition or a system of ideas intended to explain something, especially one based on general principles independent of the thing to be explained.

 

tides

The alternate rising and falling of the surface of the ocean and water bodies (such as gulfs and bays) connected with the ocean that occurs usually twice a day, and is caused by the gravitational attraction of the sun and moon occurring unequally on different parts of the Earth.

 

tissue

An aggregate of cells usually of a particular kind together with their intercellular substance that form one of the structural materials of organisms.

 

tool

A device that aids in accomplishing a task, a form of technology.

 

 

trait

An inherited characteristic.

 

transform

To change in composition or structure.

Top A B C D E F G  H I J K L M N O P Q R S T U V W X Y Z

U

unit

A determinate quantity (such as of length, time, heat or value) adopted as a standard of measurement.

 

unity

The state of being united into a whole.

 

uplift

To cause (a portion of Earth's surface) to rise above adjacent areas.

Top A B C D E F G  H I J K L M N O P Q R S T U V W X Y Z

 V

variable

A quantity that may assume any one of a set of values.

 

velocity

The rate of change of position and direction with respect to time.

 

virus

Any of various submicroscopic pathogens consisting essentially of a particle of nucleic acid enclosed in protein and able to replicate only within a living cell.

 

volcano

A vent in the crust of the Earth or another planet from which usually molten rock, ash and steam are ejected.

Top A B C D E F G  H I J K L M N O P Q R S T U V W X Y Z

W

water cycle

The sequence of conditions through which water passes from vapor in the atmosphere through precipitation upon land or water surfaces and ultimately back into the atmosphere as a result of evaporation and transpiration.

 

wave

A disturbance or variation that transfers energy progressively from point to point in a medium, and that may take the form of an elastic deformation or of a variation of pressure, electric or magnetic intensity, electric potential, or temperature.

 

wavelength

The distance between successive crests of a wave.

 

weather

The state of the atmosphere with respect to heat or cold, wetness or dryness, calm or storm, clearness or cloudiness.

 

weathering

To subject to the action of the elements.

X

Y

Z

Top A B C D E F G  H I J K L M N O P Q R S T U V W X Y Z

References

Chambers, Dictionary of Science and Technology. New York: Chambers Harrap Publishers Ltd., 1999.
Merriam-Websters' Collegiate Dictionary, 10th Ed. Springfield, Mass.: Merriam-Webster, 1993. www.britannica.com
The New Oxford American Dictionary. New York : Oxford University Press, 2001.
Webster's New World Dictionary of the American Language, New York : Simon and Schuster, 1984.
Webster's II New Riverside Dictionary Revised Edition.
Boston : Houghton Mifflin Co., 1996.