6TH GRADE SCIENCE GLOSSARY
Keep the glossary in your science folder. It should be in class every day. Highlight the words as we learn them.
We will also highlight key words in the definitions. Keep your 3 x 5 cards.
FCAT science words: 5 – mastered by 5th; 8 – mastered by 8th; and 11 – mastered by 11th grade.
abiotic factor - a nonliving physical or chemical part of an ecosystem; describes the nonliving part
of the environment, including water, rocks, light, and temperature. 8
abrasion - the grinding and wearing away of rock surfaces through the mechanical action of other rock or sand particles.
absolute magnitude - amount of light a star actually gives off.
absorption (absorb) - the process of taking in; soaking up; or making a part of something.
abyssal plain - a large, flat, almost level area of the deep-ocean basin.
acceleration - rate at which speed or direction changes; can be found by dividing the change in speed by the given
time, usually expressed in meters per second. 8
accuracy - the extent to which a measurement is in proximity to the standard or expected value. 11
acid - a substance that increases the H+ concentration when added to a water solution. 11
acid precipitation - rain, sleet, or snow that contains a high concentration of acids.
acid rain - rain that has become more acidic than normal due to pollution.
activation energy - the least amount of energy required to start a particular chemical reaction. 11
active transport - the movement of molecules from where they are less crowded to where they are more crowded; the
process of using energy to move materials through a membrane.
adaptation - any structure or behavior that helps an organism survive in its environment; a characteristic of an
organism that increases its chance of survival in its environment; 5 a particular development, behavior, or
physiological change in a population of organisms, in response to changes in the populations. 11
adenosine triphosphate (ATP) - a molecule that acts as the main energy source for cell processes.
adoptive family - the legal addition of children to the family of non-biological parents.
air mass - large body of air that has nearly the same temperature and humidity as the Earth’s surface over which it formed.
air pollution - harmful material added to the air by the introduction of pollutants from human and natural sources
that can cause damage to living things and the environment.
air pressure - the measure of the force of air molecules pushing on an area.
air resistance - force of air on moving objects. 8
alga (plural-algae) - protists that live mostly in water and use sunlight as a source of energy.
allele - any of two or more alternate forms of a gene that an organism may have for a particular trait. 8
alloy - solid metal dissolved in another solid metal.
altitude - the distance above sea level.
alveolus (plural-alveoli) - grape-like cluster of tiny ―balloons‖ in the lungs.
ameba (amoeba) - microscopic, unicellular Protist that moves using pseudopod.
amino acid - building block of protein; an organic molecule containing an amino (-NH2) and a carboxyl(-COOH)
group from which proteins are synthesized. 11
amorphous solid - solid that does not keep a definite shape.
amphibian - a cold-blooded vertebrate animal that lives in water when it is young and as an adult, it moves onto land.
amplitude - measure of the energy a wave carries; the maximum distance that the particles of a wave’s medium
vibrate from their rest position; in any periodic function, the maximum absolute variation of the function. 8
anabolic (anabolism) - building up process.
anal pore - tiny opening through which a paramecium and other unicellular organisms eliminates waste.
analyze (analysis/plural-analyses) - to separate into parts in order to determine what something is or how it works; to
examine in detail.
anatomy - the study of the structure of the body.
anemometer - an instrument used to measure wind speed.
angiosperm - a plant that has flowers and produces seeds enclosed in fruit.
Animalia (Animal) - a kingdom made up of complex, multicellular organisms that lack cell walls, can usually move
around, and quickly respond to their environment.
anion - an atom that has gained electrons; a negative ion.
anther - the part of the stamen that produces pollen.
antibiotic - substance produced by helpful bacteria that destroys or weakens disease-causing bacteria.
antibody - a substance produced in and by the body that protects against specific disease infections. 2
anticline - upward fold in a rock layer.
anticyclone - the rotation of air around a high-pressure center in the direction opposite to Earth’s rotation.
aorta - largest artery in the body.
apogee - point of the moon’s orbit farthest from the Earth.
apparent magnitude - brightness of a star as it appears from Earth.
aqueous - a solution containing water. 11
Archaean (plural-Archaea) - a kingdom made up of unicellular prokaryotic cells that can survive in extreme
archeology (archaeology) - the study of the cultural remains of ancient people.
area - a measure of the size of a surface or a region.
artery - blood vessel that carries blood away from the heart.
arthropod - an invertebrate animal with an exoskeleton, a segmented body, and jointed legs.
asexual reproduction - formation of an organism from a single cell; form of reproduction in which new individuals
are formed without the involvement of gametes. 8
assumption (assume) - is something taken for granted or accepted as true without proof.
asteroid - tiny chunks of rock of varying sizes that orbit the sun.
asteroid belt - area in space where hundreds of thousands of asteroids orbit the sun between Mars and Jupiter.
asthenosphere - the soft layer of the mantle on which the tectonic plates move.
astronomical unit (AU) - average distance from Earth to the sun, which is used to measure vast distances in space.
(approximately 150 million kilometers) 11
astronomy - study of planets, stars and other objects beyond the Earth.
atmosphere - the layers of gas that surround Earth, other planets, moons or stars. 5
atom - tiny particle of matter consisting of a nucleus that contains protons and neutrons and an electron cloud that
contains electrons; the smallest unit of a chemical element that can still retain the properties of that element; 5
building block of matter.
atomic mass - average of the masses of all the existing isotopes of an element.
atomic mass unit (amu) - unit used to measure the masses of subatomic particles; a proton has a mass of one amu.
atomic number - number of protons in the nucleus of an atom; number that identifies the kind of atom; the number
determines an element’s placement on the periodic table. 11
ATP - see adenosine triphosphate.
atrium (plural-atria) - upper heart chamber.
aurora - bands of light given off by collisions of particles in the Earth’s upper atmosphere.
autotroph - organism that makes its own food from simple substances; producer; an organism that captures energy
from sunlight and uses it to produce energy-rich carbon compounds, usually through the process of photosynthesis.
average speed - distance traveled divided by the time it takes to travel this distance.
axis (plural-axes) - imaginary line drawn through the center of a body around which the body rotates or spins; a
reference to the line in a coordinate system or graph. 5
bacillus (plural-bacilli) - rod-shaped bacterium.
Bacteria - a kingdom made up of unicellular prokaryotic cells that usually have a cell wall and reproduce by binary fission.
bacteriophage - virus that infects bacterial cells.
bacterium (plural-bacteria) - unicellular, heterotrophic microorganism containing no nuclear membrane.
balanced forces - describes forces acting on an object that cancel each other.
bar graph - tool that uses bars to show the relationships between variables; can be horizontal or vertical and can
display any numerical data.
barometer - an instrument that measures air pressure in the atmosphere.
base - a substance that increases the OH- concentration of a solution; a proton acceptor. 11
batholith - huge, irregularly shaped intrusion that extends deep in the Earth’s crust.
bedrock - the layer of rock beneath soil.
behavior - an organism’s action in response to a stimulus.
benthic - the region near the bottom of a pond, lake, or ocean.
benthos - organisms that live at the bottom of oceans or bodies of fresh water.
bias - a preference for a person or thing that interferes with impartial judgment; a prejudice.
big bang theory - states the universe was formed by the explosion of a small amount of very dense and hot matter.
bile - substance produced by the liver that aids in digestion.
binary fission - a form of asexual reproduction for prokaryotic cells such as bacteria.
binary star - double star system in which two stars revolve around each other. 3
binomial nomenclature - naming system in which organisms are given two names: a genus and species.
biodiversity - the existence of a wide range of different species in a given area or specific period of time. 8
biology - the study of life and all living things; ecology, zoology, and botany are examples of biological sciences.
biomass - plant material, manure, or any other organic matter that is used as an energy source.
biomes - large geographic areas with similar climates and ecosystems; the six most common are tundra, taiga,
temperate forest, tropical rain forest, grassland, and desert; a complex biotic community characterized by the
interaction of living organisms and climatic factors. 11
biotic factor - a living thing in an ecosystem; describes the living part of the environment relating to, caused by, or
produced by living organisms. 8
biosphere - all living organisms on Earth in the air, on the land, and in the waters; the part of Earth where life exists.
black hole - core of a very massive star that remains after a supernova explosion.
blizzard - a blinding snow storm with winds of at least 56 km/hr, usually with temperatures below -7 oC.
boiling - process in which particles of a liquid change to gas, travel to the surface of the liquid and then into the air.
boiling point - temperature at which a liquid boils.
bone - a hard stiff material containing the minerals calcium and phosphorus.
botany - study of plants.
Boyle’s Law - law stating that the volume of a fixed amount of gas varies indirectly with the pressure of the gas.
bronchus (plural-bronchi) - tube that branches off from the trachea.
budding - reproductive process in yeast, in which a new yeast cell is formed from a tiny bud.
caldera - a large, circular depression that forms when the magma chamber below a volcano partially empties and
causes the ground above to sink.
calorie - unit of energy; the amount of heat needed to raise one gram of water one degree Celsius at standard
atmospheric pressure. 8
capillary - tiny thin-walled blood vessel.
carbohydrate - organic compound made up of the elements carbon, hydrogen and oxygen, and a main source of
energy for living things; include sugars and starches used for energy or as structural materials.
carbon cycle - the continuous movement of carbon through Earth, its atmosphere, and the living things on Earth.
cardiac muscle - muscle found only in the heart.
carnivore - an animal or plant that consumes or obtains nutrients from animals. 5
carrying capacity - the maximum size that a population can reach in an ecosystem.
cartilage - a strong, flexible connective tissue that supports such structures as the nose and ears.
catabolic (catabolism) - breaking down process.
catalyst - substance that speeds up or slows down chemical reactions, but is not itself changed by the reaction; a
substance that speeds up or slows down the rate of a reaction without being consumed or altered. 11
cation - an atom that has lost electrons; a positive ion.
cause - the reason for an action or a condition.
cell - smallest, basic unit of structure and function in a living thing; building block of life.
cell membrane - thin, flexible envelope of protoplasm that forms the outer covering of an animal cell and that is
inside the cell wall of a plant cell; controls movement of materials into and out of the cell.
cell theory - major theory based on observations and conclusions by many scientists that states that the cell is the basic
unit of life, organisms are composed of one or more cells, and all cells come from other cells.
cellular respiration (respiration) - a process in which cells use oxygen to release energy stored in sugars.
cellulose - forms the rigid cells walls of plants; organic compound made of long chains of glucose molecules.
cell wall - outermost boundary of plant and bacterial cells.
Celsius (oC) - temperature scale used in the metric system at which water freezes at 0o and boils at 100o.
cementation - process by which sediments are cemented together by minerals dissolved in water to form sedimentary rock.
centrifugal - the motion away from the center of axis. 11
centrioles - one of the two tiny parts found in the centrosome composed of microtubules.
centripetal force - the force on an object required to keep this object on a circular path, pulling toward the center of
the circle. 11
centrosome - a small organelle just outside the nucleus that contains the centrioles and is involved with mitosis.
chain of infection - a series of infections that is directly or immediately connected to a particular source.
change of state - a physical change that occurs when matter changes to another state. 5
Charles’s Law (Charles’) - law stating that the volume of a fixed amount of gas varies directly with the temperature
of the gas.
chemical change - change a substance undergoes when it turns into another substance. 5 4
chemical digestion - breaking down of food by enzymes.
chemical energy - energy that is stored in the chemical composition of matter; the energy released when a chemical
compound reacts to produce new compounds.
chemical equation - description of a chemical reaction using symbols and formulas.
chemical formula - combination of chemical symbols used as a shorthand for the names of chemical substances.
chemical property - property that describes a substances ability to change into another substance.
chemical reaction - process by which a substance is changed into another substance through a rearrangement or new
combination of its atoms.
chemical rock - sedimentary rock formed from large amounts of minerals when a body of water dries up.
chemical symbol - shorthand way of representing the elements; usually consists of one or two letters, the first of
which is always capitalized, but the second is never capitalized.
chemical weathering - the breakdown and alteration of rocks at or near Earth’s surface as a result of chemical
chemistry - study of what substances are made of and how they change and combine.
chlorofluorocarbons (CFCs) - group of chemical compounds used in refrigerators, aerosol sprays, and foam
packaging that destroy ozone molecules.
chlorophyll - green substance needed for photosynthesis.
chloroplast - large, irregularly shaped organelle that contains the green pigment needed for photosynthesis.
chordate - animal with a notochord, a dorsal hollow nerve cord, and gill slits.
chromatin - the material that makes up the chromosomes found in the nucleus.
chromosome - thick, rod-like object found in the nucleus that directs the activities of the cell and passes on the traits
of the cell to new cells.
chromosphere - middle layer of the sun’s atmosphere.
cilium (plural-cilia) - small, hair-like projection on the outside of a cell used for movement.
circle graph - tool used to show the parts of a whole.
circuit - an interconnection of electrical elements forming a complete path for the flow of current. 8
circulatory system - body system that transports materials.
class - classification group between phylum and order.
classification - is the grouping of living things according to similar characteristics.
classification key - a system for identifying organisms by using pairs of descriptions.
classify - to group information, objects, or ideas based on their similarities.
clastic rock - sedimentary rocks made up of rock fragments mixed with sand, clay and mud.
cleavage - breakage of a mineral along definite lines or smooth, flat surfaces.
climate - pattern of weather that occurs in a particular area over a long period of time.
climate zone - one of the major divisions in a system for classifying the climates of different regions based on
characteristics they have in common.
climax community - community that has reached the final stage of ecological succession.
cloud - a collection of small water droplets or ice crystals suspended in the air, which forms when the air is cooled
and condensation occurs.
cnidarian - an invertebrate animal that has a body with radial symmetry, tentacles with stinging cells, and a central
coal - a fossil fuel that forms underground from partially decomposed plant material.
coccus (plural-cocci) - sphere-shaped bacterium.
coefficient - number placed in front of a chemical formula in a chemical equation so that the equation is balanced.
cold - is the absence of heat.
cold-blooded - having a body temperature that can change somewhat with changes in the temperature of the environment.
colonial - unicellular organisms that live independently but clustered side by side.
coma - cloud of gas and dust surrounding the nucleus of a comet.
comet - object made of ice, gas and dust that orbits the sun.
commensalism - an interaction between two species in which one species benefits without harming the other.
communicable - capable of spreading from one diseased person or animal to another person or animal, either directly
community - all the populations of organisms belonging to different species and sharing the same geographical area. 5
compaction - process by which layers of sediments are pressed together to form sedimentary rock.
competition - struggle among living things to get the proper amount of food, water and energy from the environment.
composition - the chemical makeup of a rock; describes either the minerals or other materials in the rock. 5
compound - substance made up of molecules that contain more than one kind of atom; two or more elements
chemically combined; a substance made up of at least two different elements held together by chemical bonds
that can only be broken down into elements by chemical processes. 5, 11
compound light microscope - microscope containing more than one lens that uses light to make an object look larger.
compound machine - combination of two or more simple machines.
compression - type of stress that squeezes rock together.
compressional wave - wave in which matter in the medium moves forward and backward in the same direction the
concentration - the relative amount of a particular substance, a solute, or mixture. 11
conclusion - the summary of the results of the experiment where data is analyzed to determine the meaning of what
happened in the experiment.
condensation - process in which a gas loses heat energy and changes into a liquid; the act of making more dense or
conditioning - process in which behavior is modified so that a response associated with one stimulus becomes
associated with another stimulus.
conduction - transfer of energy that occurs when molecules bump into each other; the transmission of heat through a
medium and without the motion of the medium; 8 the process by which energy is transferred from a warmer
object to a cooler object by means of physical contact.
conifer - cone-bearing trees and shrubs that usually keep their leaves or needles during all the seasons of the year.
conjugation - type of sexual reproduction in unicellular organisms in which hereditary material is exchanged.
conservation - controlled use and/or maintenance of natural resources; various efforts to preserve or protect natural
conservation of energy - states that energy cannot be created nor destroyed but only changed from one form to another. 8
conservation of mass (conservation of matter) - states that mass cannot be created or destroyed. 11
constant - factor in an experiment that does not change.
constellation - group of stars in which people thought they saw imaginary figures of animals or people; a star pattern
identified and named as a definite group. 5
constructive boundary - type of plate boundary where new material is added to the plates.
consumer - an organism that feeds on other organisms for food. (heterotroph) 5
continental climate - a climate that occurs in the interior of a continent, with large temperature differences between seasons.
continental drift (theory of continental drift) - states that the continents once formed a single land mass, broke up,
and drifted to their present locations.
continental glacier - large, slowly moving sheets of ice that can cover an entire continent.
continental rise - the gently sloping section of the continental margin located between the continental slope and the
continental shelf - the gently sloping section of the continental margin located between the shoreline and the continental slope.
continental slope - the steeply inclined section of the continental margin located between the continental rise and the
contractile vacuole - a cell organelle that pumps excess water out of the cell.
control (controlled variable) - standard used for comparison in an experiment; experiment run exactly the same way
as the experiment with the variable, but the variable is left out.
convection - transfer of heat energy by the circulation or movement of gases or liquids. 8
convection current - movement of fluid caused by the unequal heating of the fluid.
convergent boundary - area where two tectonic plates collide. 11
cooperation - an interaction between two or more living things in which they work together.
core - the central part of the Earth below the mantle.
Coriolis effect - the curving of the path of a moving object from an otherwise straight path due to the Earth’s rotation.
corona - outermost layer of the sun’s atmosphere.
covalent bond - a chemical bond between two atoms of the same or different elements in which each atom shares an
crater - a bowl-shaped depression that forms on the surface of an object when a falling body strikes the object’s
surface or when an explosion occurs.
crest - highest point of a wave. 8
crust - thin, solid, outermost layer of the Earth covering the mantle. 8
crystal - regular, repeating pattern of particles in a solid.
crystalline solid - solid made up of crystals. 6
cycle - a series of events or actions that repeat themselves regularly; a physical and/or chemical process in which one
material continuously changes locations and/or forms.
cyclic behaviors - innate behaviors, such as migration or hibernation that occur in a repeated pattern, often in
response to changes in the environment.
cyclone - an area in the atmosphere that has lower pressure than the surrounding areas and has winds that spiral
toward the center.
cytology - the study of cells.
cytoplasm - thick, gelatin-like substance outside the nucleus; holds the organelles.
datum (plural-data) - recorded observations and measurements.
day - the time required for Earth to rotate once on its axis.
deciduous - trees and shrubs that drop their leaves when winter comes.
decomposer - any organism that feeds or obtains nutrients by breaking down organic matter from dead organisms. 5
deforestation - destruction or cutting down of trees.
deformation - the bending, tilting, and breaking of Earth’s crust; the change in the shape of rock in response to stress.
dehydration - an excessive loss of water.
density - mass per unit volume, or how much mass is contained in a given volume of an object; number of individuals
in the same species that live in a given area. 5
deoxyribonucleic acid (DNA) - nucleic acid that stores the information needed to build proteins and carries genetic
information about an organism; present in all cellular organisms. 11
dependent variable - factor being measured or observed in an experiment; 8 a factor that responds to, or depends
on, other factors.
deposition - natural process by which sediments are laid down in new locations. (layering) 5, 8
dermis - lower layer of skin.
desalination - a process of removing salt from ocean water.
desert - driest biome on Earth; receives less than 25 cm of rain each year and supports little plant life.
development - the act, process or result of maturing.
dew point - the temperature at which air with a given amount of water vapor will reach saturation.
diaphragm - muscle at the bottom of the chest that aids in breathing.
dichotomous key - a series of questions, each with only two answers, that can be used to help identify an
organisms genus and species.
differential weathering - the process by which softer, less weather resistant rocks wear away at a faster rate than
harder, more weather resistant rocks do.
diffraction - bending of waves around a barrier (or obstruction) or traveling through an opening. 8, 11
diffusion - process by which food, oxygen, water and other materials enter and leave a cell through openings in the
cell membrane; the movement of molecules from where they are crowded to where they are less crowded.
digestion - process by which food is broken down into simpler substances.
digestive system - body system that breaks down the food into simple substances.
direct transmission - transmitting disease organisms in which the agent moves immediately from the infected person
to the susceptible person, as in person-to-person contact.
dislocation - forcing a bone out of joint.
divergent boundary - type of plate boundary where the plates move apart, such as a midocean ridge.
diversity - the quality of having many differences.
division - in the taxonomy of plants, the group smaller than a kingdom but larger than a class.
division of labor - division of the work that keeps an organism alive among the different parts of its body.
doldrums - is the windless zone of the equator.
domain - one of three divisions in a classification system based on different types of cells: archaea, bacteria, and eukarya.
dominance - tendency of certain (dominant) alleles to make the expression of their corresponding (recessive) alleles.8
ductility (ductile) - ability of a substance to be pulled into thin strands without breaking.
earthquake - the shaking of the ground caused by a sudden release of energy in the Earth’s crust. 5
echinoderm - an invertebrate sea animal with a spiny skeleton, a water vascular system, and tube feet.
eclipse - total or partial blocking out of the sun or moon by a shadow.
ecological succession - process of gradual change from one community of organisms to another.
ecology - study of how living things interact with each other and their environment.
ecosystem - an integrated unit of a biological community, its physical environment, and interactions. 5, 8
ectotherm - an animal whose body temperature changes with environmental conditions.
edema - too much water. 7
efficiency - ability of a machine to convert work input to work output; always less than 100 percent in real machines
due to some loss to friction or heat; 8 a machine’s output work divided by its input work and multiplied by 100.
effort force (Fe) - force applied to a machine.
elastic rebound - the sudden return of elastically deformed rock to its undeformed shape.
electromagnet - a magnet consisting of a coil of wire wrapped around a core that becomes strongly magnetized when
current flows through the coil producing a magnetic field. 11
electromagnetic radiation - the emission and propagation of the entire range of electromagnetic spectrum including:
gamma rays, x-ray, ultraviolet radiation, visible light, microwaves, and radio waves. 8
electromagnetic spectrum - arrangement of different forms of light in order of increasing frequency and decreasing
electromagnetic wave - transverse wave that does not need a medium to travel; whose speed in a vacuum is 300,000
kilometers per second and has varying wavelengths and frequencies; waves generated by the oscillation of a
charged particle and characterized by periodic variations of electric and magnetic fields. 11
electron - negatively charged particle that moves around the nucleus of an atom in a region called the electron cloud. 8
electron cloud - space in which electrons are most likely to be found.
electron microscope - microscope that uses a beam of electrons to magnify the image of an object.
element - pure substance made up of only one kind of atom that cannot be broken down into simpler substances by
ordinary chemical changes. 5
elevation - the height of an object above sea level.
ellipse - oval orbit.
elliptical galaxy - oval-shaped galaxy.
El Nino - disturbance of wind patterns and ocean currents in the Pacific Ocean that causes temporary climate changes
in many parts of the world.
embryo - a multicellular organism in its earliest stages of development.
emotion - a strong feeling.
endocytosis - into the cell.
endoplasmic reticulum (ER) - maze of clear tubular passageways that leads out from the nuclear membrane; involved
in the manufacture and transport of proteins.
endoskeleton - internal system of bones that protects and supports an animal’s internal organs and also provides a
place for muscle attachment; skeleton inside the body.
endospore - oval-shaped structure that protects a bacterium.
endotherm - an animal that maintains a constant body temperature.
endothermic reaction - a chemical reaction that absorbs energy.
energy - the capacity for work; a source of usable power. 5
energy conversion - a change from one form of energy to another.
energy efficiency - a measurement of useable energy after an energy conversion; the ratio of useable energy to the
total energy after an energy conversion.
energy level - most likely location in the electron cloud in which an electron can be found.
energy pyramid - a pyramidal diagram that compares the amount of energy available at each position, or level, in the
feeding order; 5 a model used to show the amount of energy available to living things in an ecosystem.
energy transfer - a change of energy from one form to another. 5
engineering - the application of science and mathematics to solve real-life problems.
entropy - a measure of randomness or disorder of a closed system. 8
environment - the sum of conditions affecting an organism, including all living and nonliving things in an area, such
as plants, animals, water, soil, weather, landforms, and air. 5
enzyme - special type of protein that regulates chemical activities within the body.
epicenter - place on the Earth’s surface directly above the focus of an earthquake.
epidermis - outermost layer of the skin.
epiglottis - small flap of tissue that closes over the windpipe.
equator - imaginary line at 0o latitude that circles the Earth halfway between the north and south geographical poles
and divides the Earth into two equal halves. 5
equinox - occurs twice yearly when the sun is directly above the equator, with the result that day and night are the
same length all over the world; the vernal equinox occurs March 20 or 21 and the autumnal equinox occurs
September 22 or 23.
erosion - process of wearing away of the Earth’s surface by breaking down and carrying away soil, rock, 8
or sediment by wind, water, ice or gravity. 5, 8
esophagus - pipe-shaped tube that transports food to the stomach.
esteem - favorable regard; respect.
estimation - method of making a rough measurement.
estivation - behavioral adaptation for survival during hot, dry summer months, during which an animal becomes
inactive; in amphibians, involves hiding in cooler, more humid ground.
estrogen - hormone produced by ovaries; responsible for the development and growth of secondary sex characteristics
estuary - a shoreline area where fresh water from a river mixes with salt water from the ocean.
euglena - microscopic, unicellular Protist that is usually green and moves using a flagellum (pl-flagella.)
Eukarya - a domain made up of all eukaryotes.
eukaryotic cell (eukaryotes) - the more complex type of cell with a true nucleus. (kingdoms: Protista, Fungi,
Plantae, and Animalia)
evaporation - process in which a liquid changes into a gas by absorbing heat energy, usually at the surface. 5
evaporite - sedimentary rock formed when water evaporates and leaves behind mineral deposits.
evidence - a thing or things helpful in forming a conclusion or judgment.
excretion - process of getting rid of waste materials.
excretory system - body system that removes body wastes.
exhale - to breathe out.
exocytosis - out of the cell.
exoskeleton - lightweight body covering that protects and supports an arthropod’s body, prevents it from drying out,
and is shed by molting; a hard outer covering.
exosphere - upper atmosphere.
exothermic reaction - a chemical reaction that releases energy.
experiment - an organized procedure that is carried out and repeated under controlled conditions in order to discover,
demonstrate, or test a hypothesis; includes all components of the scientific method. 5
experimental bias - an error that distorts results in a particular way; something that causes certain outcomes to be
favored over others.
extended family - parents, children, and other relatives such as grandparents, aunts, uncles, and so forth.
extensor - a muscle that straightens a joint.
extinction - the permanent disappearance of a species.
extrusive rock - igneous rock formed from melted rock or lava that cools and hardens at or near the Earth’s surface.
eyespot - light-sensitive organelle in lower organisms.
fact - the quality of being real or actual.
family - classification group between order and genus; the oldest and most basic social unit.
fat - energy-rich organic compound made up of carbon, hydrogen and oxygen, that is solid at room temperature.
fault - crack or break in the Earth’s crust along which movement has occurred. 11
fermentation - energy-releasing, chemical process in which sugars and starches are changed into alcohol and carbon
dioxide when no oxygen is present.
fern - seedless, vascular, fringe-leafed plant that grow in cool, wooded environments.
fertilization - joining of egg and sperm to make a new cell.
fiber - a structure that resembles a thread; it can be a strand of nerve tissue or a cell that is threadlike.
fibrin - substance that traps blood cells and plasma, forming a scab.
first aid - emergency medical care for someone who has been hurt or who is sick.
first law of thermodynamics - states the internal energy in a system remains constant and the change in thermal
energy of a system is equal to the work done on the system. 11
flagellum (plural-flagella) - whip-like structure that propels some one-celled organisms.
flammability - ability to burn.
flexor - a muscle that bends a joint when it contracts.
flower - the reproductive structure of an angiosperm, containing male and female parts.
focus (plural-foci or focuses) - point beneath the Earth’s surface where rocks first break and move during an earthquake.
fold - bend in a rock.
folding - the bending of rock layers due to stress.
foliated rock - texture of some metamorphic rocks in which mineral crystals are arranged in parallel bands along
which the rocks tend to break.
food chain - transfer of energy through various stages as a result of feeding patterns of a series of organisms. 5 9
food vacuole - a spherical part that forms from pseudopods that engulf and digest captured food.
food web (food cycle) - the interconnected feeding relationships in a food chain found in a particular place and time. 5
foot wall - block of rock below a fault.
force - a quality that tends to produce movement or acceleration of a body in the direction of its application; push or a
pull; can be measured by the amount of acceleration it can give a mass. 5; has size and direction.
fossil - remains or traces (whole or part) of past plant and animal life that has been preserved in sedimentary rock. 5
fossil fuel - nonrenewable energy resource that began to form millions of years ago from remains of once-living plants
and animals; provides energy and includes coal, oil, and natural gas. 8
foster family - child care provided in a family setting by non-biological parents.
fracture - mineral breakage that forms an irregular surface that may be rough or jagged; a bone break.
freezing - change of a liquid to a solid.
freezing point - temperature at which a liquid changes to a solid.
freezing rain - rain that freezes when it hits the ground or another surface and coats the surface with ice.
frequency - number of waves that pass a given point in one second; measured in waves per second, or hertz (Hz). 8
friction - force that resists motion between two objects in contact and that always acts opposite to the direction of
front - the boundary between air masses of different densities and usually different temperatures.
fruit - the ripened ovary of a flowering plant that contains the seeds.
fulcrum - pivot point of a lever. 5
full moon - phase of the moon when the entire lighted side of the moon is visible.
function - the special, normal, or proper activity of an organ or part. ( job; what it does; physiology)
Fungus (plural-Fungi) - a kingdom made up of multicellular eukaryotic cells that have no movement, reproduce by
spores, and get food by breaking down substances to absorb the nutrients.
galaxy - a large collection of stars, gases, and dust that are part of the universe bound together by gravitational forces.
(EX - Milky Way) 5
gall bladder - organ in the digestive system that stores bile.
gamete - a sex cell: the egg or the sperm.
gamma ray - electromagnetic radiation with wavelengths shorter than those of x-rays and having greater energy and
gas - phase in which matter has no definite shape or volume. 5
gasohol - a mixture of gasoline and alcohol that is used as a fuel.
gem - rare, very valuable and beautiful mineral.
gene - a specific part of a chromosome or sequence of DNA that determines a particular feature or characteristic in an
genetic material - the nucleic acid (DNA) that is present in all living cells and contains the information needed for a
cell’s growth, maintenance, and reproduction.
genotype - the sum total of the genetic information contained in an organism. 11
genus (plural-genera) - group of organisms that are closely related; classification group between family and species.
geocentric theory - belief that the Earth is at the center of the universe.
geologist - scientist that studies the Earth’s origin, history, and structure.
geosphere - all the features on Earth’s surface and everything below the surface.
geothermal energy - energy produced from the heat energy within the Earth that can be used to generate electricity.
germ - a microorganism, especially one that causes disease.
germination - the beginning of growth of a new plant from a spore or a seed.
gestation - in mammals, the period of time spent by a developing offspring inside the mother’s body.
giant star - star with a diameter 10 to 100 times as large as the sun.
gill - a respiratory organ that filters oxygen dissolved in water.
glacier - large mass of moving ice and snow.
Global Positioning System (GPS) - determines the position, speed, and direction of a person anywhere on Earth.
global warming - rise in global temperatures because of the increase of greenhouse gases in the atmosphere.
global winds - winds that travel long distances in steady patterns over several weeks.
globular cluster - stars grouped in huge spherical clusters.
glucose - simple sugar into which all carbohydrates are broken down in the body to produce energy.
Golgi apparatus (body) - a secretory structure consisting of a stack of flat sacs that store and convert or modify proteins.
gram (g) - basic unit of mass in the metric system. (kilogram is commonly used instead of gram)
graph - diagram that shows the relationship; tool used to collect, organize, and summarize data in a visual way 10
so that it is easy to use and understand.
grasslands - temperate and tropical regions that receive between 25 cm and 75 cm of precipitation each year and are
dominated by climax communities of grasses.
gravity - the force that objects exert on each other because of their mass. 5
greenhouse effect - heat-trapping process in which heat becomes trapped by cloud layers and cannot escape back into
space; prevents Earth from being too cold to support life.
greenhouse gases - gases, such as carbon dioxide and methane, that absorb and give off infrared radiation as part of
the greenhouse effect.
groundwater - water that soaks into the ground and collects in the small spaces between bits of rock and soil.
growth - a stage in the process of growing; a measure of progressive development.
gullet - funnel-shaped structure in the paramecium and other unicellular organisms.
gymnosperm - a plant that produces seeds that are not enclosed in flowers or fruit.
habitat - a place in an ecosystem where an organism normally lives; 5 the natural environment in which a living
thing gets all that it needs to live.
hail - layered lumps or balls of ice that fall from cumulonimbus clouds.
half-life - the amount of time required for half of an original sample of radioactive material to decay or undergo
radioactive transformation. 11
halophile - Archaea that tolerate salty surroundings.
hanging wall - block of rock above a fault.
hardness - ability of a mineral to resist being scratched.
Haversian canal - passageway running through the thick bone, containing blood vessels and nerves.
heat - transfer of energy from an object with a higher temperature to an object with a lower temperature. 5
heat of fusion - the amount of heat energy required to convert a unit mass of substance from a solid to a liquid
through melting at a constant temperature and pressure. 11
heat of vaporization - the amount of heat energy needed to change a unit mass of substance from a liquid to a gas at
its boiling point. 11
heliocentric theory - belief that the planets travel in orbits around the sun.
hemisphere - northern or southern half of the Earth.
hemoglobin - iron-containing substances in red blood cells.
herbivore - animal that eats only plants. 5
heredity - the passing of genetic traits from parent to offspring.
Hertzsprung-Russell diagram (HR diagram) - chart of the relationship between the absolute magnitude and the
surface temperature of stars.
heterotroph - organism that is not able to make its own food and thus feeds on other organisms; consumer.
heterozygous - cell or organism that has two different alleles for a particular trait. 8
hibernation - behavioral adaptation for survival during cold, winter months, where an animal becomes inactive and
its metabolic needs are lowered; in amphibians, involves burying themselves in mud or leaves until
temperatures become warmer.
high-pressure system - a generally calm and clear weather system that occurs when air sinks down in a high-pressure
center and spreads out toward areas of lower pressure as it nears the ground.
high tide - bulge in the ocean on the side of the Earth facing the moon and on the opposite side.
homeostasis - ability of an organism to keep conditions inside its body the same even though conditions in its external
homozygous - cell or organism that has identical rather than different alleles for a particular trait. 8
hormone - a chemical substance made in the body that triggers a specific response, such as growth.
host - organism in which a parasite lives; a person or organism in whom an infectious pathogen can live and multiply.
host cell - a cell that a virus infects and uses to make copies of itself.
hot spot - a volcanically active area of Earth’s surface, commonly far from a tectonic plate boundary.
humidity - amount of water vapor in the air.
humus - dark, organic material formed in soil from the decayed remains of plants and animals.
hurricane - large, swirling, low-pressure system that forms over tropical oceans and has winds of at least 120 km per hour.
hydroelectric energy (power) - production of electricity by the flow of water.
hydrosphere - all of the water on the Earth; 97 percent is salt water and only 3 percent is fresh water.
hypha (plural-hyphae) - threadlike tubes that form the structural parts of the body of a fungus.
hypothesis (plural-hypotheses) - suggested solution or prediction to a scientific problem; ―educated‖ guess.
ice age - a period of time during which surface temperatures drop significantly and huge ice sheets 11
spread out beyond the polar regions.
igneous rock - type of rock formed from cooled and hardened magma or lava. 5
immune system - the human body’s network of cells and organs that produce disease-fighting antibodies.
impermeable membrane - when materials will not pass through a membrane.
imprinting - type of learning in which an animal forms a social attachment to another organism soon after birth or hatching.
inclined plane - simple machine that uses a slanted surface that makes it easier to move a mass from a lower point to
a higher point; allows heavy loads to be lifted by using less force over a greater distance. 5
incubation - the process of keeping eggs warm by bodily heat until they hatch.
incubation period - the time between contact with a source of infection and the outbreak of symptoms.
independent variable - the one factor changed by the person doing the experiment in order to study changes in the
dependent variable. 8
indicator - a chemical compound that changes color depending on the pH of the solution or other chemical change. 11
indirect transmission - transmitting disease organisms in which the agents do not pass directly from an infected
person to a susceptible person but by means of an intermediate host.
inertia - property of a mass to resist changes in motion; measure of an object’s ability to remain at rest or to keep
moving unless overcome by a force. 5, 8
infection - invasion of the body by organisms.
infectious disease - disease caused by microorganisms living in or on the body.
inference (infer) - conclusion based on an observation.
infrared radiation - invisible heat energy from the sun.
ingestion - eating.
inhale - to breathe in.
innate behavior - behavior that an animal is born with and does not have to learn.
inner core - solid, innermost layer of the Earth.
inorganic - composed of material that is not and never was living.
inorganic compound - compound that does not usually contain the element carbon.
insect - an arthropod with three body segments, six legs, two antennae, and compound eyes.
instinct - complex pattern of innate behavior.
interaction - the condition of acting or having an influence upon something.
interference - ability of two or more waves to combine and form a new wave when they overlap; can be constructive,
forming a larger wave, or destructive, forming a smaller wave.
International Date Line - transition line for calendar days, located at the 180o meridian (longitude).
International System of Units (SI) - a system of units used in science; metric system.
intertidal zone - portion of the shoreline that is covered with water at high tide and exposed to the air at low tide.
intrusion - igneous rock formed when magma forces its way into sedimentary rock and hardens below or on the
intrusive rock - rock that forms from melted rock or magma that cools and hardens deep below the Earth’s surface.
invertebrate - an animal without a backbone; about 97 percent of animals are invertebrates.
investigation - a procedure that is carried out in order to observe a response caused by a stimulus; not a complete
ion - an atom that loses or gains electrons; charged atom.
ionosphere - layer of electrically charged particles in the thermosphere.
isobar - a line on a weather map connecting places that have the same air pressure.
isostasy - balance between the downward force of the crust and the upward force of the mantle.
isotope - atom of a substance that has the same number of protons but a different number of neutrons as another atom
of the same substance. 11
jet stream - narrow belt of strong winds that flows from west to east at great speeds near the top of the troposphere.
joint - crack in the crustal rock; a place where bones meet.
Kelvin (K) - the temperature scale (SI unit) that has its zero at absolute zero where matter stops moving; water freezes
at 273.15o and boils at 373.15o. 11
kidney - major excretory organ.
kilogram - see gram.
kinetic energy - the energy possessed by a body because of its motion. 5
kingdom - largest classification grouping.
laccolith - dome-like intrusion that pushes overlying rocks into an arch and has a flat floor.
land breezes - nightly movements of air created when cold air over the land forces up the warmer air above the sea. 12
large intestine - organ in the digestive system in which water is absorbed and undigested food is stored.
larva (plural-larvae) - a free-living early form of a developing organism that is very different from its adult form.
larynx - voice box.
lateral fault - crack along which the blocks of rock move horizontally past one another.
lateral moraine - till deposited along the sides of a glacier.
latitude - measure of distance in degrees north or south of the equator.
lava - hot, molten rock that has reached the Earth’s surface.
law - a rule or principal describing a physical relationship that always works in the same way under the same conditions.
law of conservation of energy - states that no matter how energy is transferred or transformed, all of the energy is
still present in one form or another.
law of conservation of matter - states that matter is neither created nor destroyed, only changed in form.
law of definite proportions - states that a given compound is always made of the same elements in the same
proportion by mass.
law of inertia - Newton’s law that states that an object’s motion will not change unless that object is acted on by an
law of superposition - states that in layers of sedimentary rocks, younger rocks normally lie on top of older rocks.
leaching - the removal of substances that can be dissolved from rock, ore, or layers of soil due to the passing of water.
lens - curved pieces of glass that bend light rays as they pass through it.
lever - simple machine made from a rod or plank that pivots about a point (fulcrum); used to transmit and enhance
power or motion. 5
lichen - organism made up of a fungus and a green alga.
life cycle - the entire sequence of events in an organism’s growth and development. 5
life span - maximum length of time a particular organism can be expected to live.
life zone - narrow region of space around a star in which a planet that contains life can exist.
ligament - a strong, stringy connective tissue that fastens the bones together in a moveable joint.
light - electromagnetic radiation that lies within the visible range. 5
lightning - an electric discharge that takes place between two oppositely charged surfaces, such as between a cloud
and the ground, between two clouds, or between two parts of the same cloud.
light-year - distance light travels in one year. (about 9.46 trillion km)
limiting factor - a factor or condition that prevents the continuing growth of a population in an ecosystem.
line graph - tool used to show the relationship between two variables.
lipids - include fats, oils, or waxes used for energy or as structural materials that do not dissolve in water.
liquid - phase in which matter has no definite shape but does have a definite volume. 5
liter (L) - basic unit of volume in the metric system.
lithosphere - topmost, solid part of the Earth.
liver - organ that produces bile.
loess - many layers of fine sand and silt deposited in the same area.
longitude - measure of distance east and west of the prime meridian.
longitudinal wave - the particles of the medium vibrate in the direction of the moving energy; the type of wave made
by sound energy;
love - a deep, tender feeling of affection and emotional attachment.
low-pressure system - a large and often stormy weather system that occurs when air moves around and into a
low-pressure center, then moves up to higher altitudes.
low tide - lowest level of the ocean that occurs between the two high tides.
lunar eclipse - eclipse that occurs when the Earth comes directly between the sun and the full moon.
lung - a respiratory organ that absorbs oxygen from the air.
luster - way a mineral reflects light.
lysosome - small, round structure involved with the digestive activities of a cell.
machine - any device that makes doing work easier.
magma - hot, molten rock deep inside the Earth.
magma chamber - the body of molten rock that feeds a volcano.
magnetic - having the property of attracting iron and certain other materials by virtue of a surrounding field of force. 5
magnetic field - the region where magnetic force exists around magnets or electric currents. 8
magnetosphere - magnetic field of a planet.
main-sequence star - star located in an area that runs from the upper left to the lower right of the Hertzsprung-Russell diagram.
malleability (malleable) - ability of a substance to be hammered into thin sheets without breaking. 13
mammal - a warm-blooded vertebrate animal whose young feed on milk produced by the mother’s mammary glands.
mantle - layer of the Earth that extends from the bottom of the crust to the Earth’s core.
maria - dark, broad, smooth, lowland area on the moon.
marine climate - a climate influenced by a nearby ocean, with generally mild temperatures and steady precipitation.
marrow - the soft tissue filling the ends and inner spaces of bones.
mass - measure of the amount of matter in an object. 5, 8
mass number - sum of the protons and the neutrons in the nucleus of an atom. 11
matter - what all materials are made of; anything that has mass and volume. (gas, liquid, or solid) 5
maturation - the emergence of personal and behavioral characteristics through growth processes.
measurement - way to describe the world with numbers; can describe objects and events with length, volume, mass,
temperature, and rates.
mechanical advantage (M.A.) - comparison of the effort force to the resistance for a machine; output force divided
by input force.
mechanical digestion - physical action of breaking foods into smaller parts.
mechanical energy - the amount of work an object can do because of the object’s kinetic and potential energies.
mechanical wave - wave that can travel only through matter; can be either a transverse or a compressional wave.
mechanical weathering - the process by which rocks break down into smaller pieces by physical means.
medium - the material through which a wave travels. (gas, liquid, or solid)
meiosis - form of cell division that halves the number of chromosomes in a male and female sex cell as they form. 8
melting - change of a solid to a liquid.
melting point - temperature at which a solid changes to a liquid.
membrane - a thin layer of tissue that surrounds or lines a cell, a group of cells, or a cavity; any barrier separating
two fluids. 11
meniscus - the surface of a liquid.
Mercator projection - map projection that has correct shapes of continents, but their areas are distorted; has lines of
longitude drawn parallel to each other.
meridian - imaginary line used to measure longitude that runs north and south between the Earth’s geographic poles.
mesosphere - the layer of the atmosphere between the stratosphere and the thermosphere and in which temperature
decreases as altitude increases; also the strong, lower part of the mantle between the asthenosphere and the outer core.
metabolism - all chemical activities in an organism essential to life.
metal - element that is a good conductor of heat and electricity, is shiny, has a high melting point, is ductile and
malleable and forms positive ions.
metalloids - elements that have characteristics of both metals and nonmetals, generally are brittle and dull, and are
poor conductors of heat and electricity.
metamorphic rock - type of rock changed by heat, pressure or chemical action. 5
metamorphism - changing of one type of rock into another as a result of tremendous heat, great pressure or chemical reactions.
metamorphosis - a developmental process in which an animal changes drastically in body form between the juvenile
and the adult; can be complete (egg, larva, pupa, and adult) or incomplete (egg, nymph, and adult).
metazoan - multicellular animals that cause scabies and pubic lice.
meteor - streak of light produced by a burning meteoroid in Earth’s atmosphere.
meteorite - chunks of rock that strike the Earth’s surface.
meteoroid - chunks of rock that orbit the sun.
meteorologist - a scientist who studies weather.
meter (m) - basic unit of length in the metric system.
methanogen - Archaea that produce methane as a waste product of metabolism.
metric system - universal system of measurement.
microbiology - study of microorganisms.
microclimate - the climate of a smaller area within a subclimate.
microorganism - a very small organism that can be seen only with a microscope.
microscope - instrument that produces an enlarged image of an object.
microscopic - relating to an object too small to be visible without the use of a microscope. 5
microwave - a high frequency electromagnetic wave used to cook or heat food.
mid-ocean ridge - a continuous, seismic mountain range extending across the floor of the world’s major oceans; area
where two oceanic plates are moving away from each other; area where new crustal material may be released. 11
migration - instinctive seasonal movement of animals, usually to find food or to reproduce in a better environment.
Milky Way - galaxy in which the Earth’s solar system is located. 14
mineral - is a naturally occurring, inorganic solid that has a definite chemical composition and crystal shape.
mitochondrion (plural-mitochondria) - oval-shaped organelle that is referred to as the powerhouse of a cell.
mitosis - duplication and division of the nucleus and of the chromosomes during cell reproduction; a process of
nuclear division in cells during which the number of chromosomes is reduced by half. 8
mixture - two or more pure substances that are mixed but not chemically combined. 5
mobile - able to move from place to place.
model - a pattern, plan, representation, or description designed to show the structure or workings of an object, system,
Mohs hardness scale - scale used to determine the hardness of a mineral.
molecule - smallest particle of a substance that has all the physical and chemical properties of that substance; made up
of two or more atoms that are chemically bonded. 11
mollusk - an invertebrate animal with a soft body, muscular foot, and a mantle.
molting - the process of an arthropod shedding its exoskeleton to allow for growth.
momentum - a vector quantity that is the product of an object’s mass and velocity; the general effect of ongoing motion. 11
monsoon - major seasonal land and sea breeze; a wind that changes direction with the seasons.
moon - a natural satellite that revolves around a planet. 5
moon phase - the fraction of the moon’s disc that is illuminated as seen from Earth; (the eight moon phases: new moon,
waxing-crescent, first quarter, waxing-gibbous, full moon, waning-gibbous, last quarter, waning-crescent.) 5
moss - seedless, nonvascular, small, grass-like plant that live in moist, cool environments.
motion - a change of position over time.
multicellular - having many cells.
muscle - tissue that has the ability to contract or shorten; a special tissue that causes movement.
muscle strain - a problem that occurs when a muscle is overused after it has not been exercised for several weeks.
muscle tear - the separating of the fibers of a muscle by sudden force or stretching.
mutation - the process by which a gene undergoes a change in DNA sequence or a structural change. 11
mutualism - an interaction between two species in which both benefit.
nanotechnology - the study of the science and technology of building electronic circuits and devices from single
atoms and molecules.
natural gas - a mixture of gaseous hydrocarbons located under the surface of the earth, often near petroleum deposits;
used as a fuel.
natural resource - any type of matter or energy from Earth’s environment that humans use to meet their needs.
natural selection - the theory stating every organism displays slight variations from other organisms of its kind, and
the struggle for limited natural resources results in individuals with certain natural variations adapted to their
specific environments. 11
neap tide - high tide lower than usual; a twice-monthly tide of minimal range that occurs when the sun, moon, and
Earth are at right angles to each other, thus decreasing the total tidal force exerted on Earth. 8
nebula - massive cloud of dust and gas in which stars are probably born.
nebular theory - idea that the solar system began in a vast gas cloud.
nekton - all organisms that swim actively in open water, independent of currents.
nephron - microscopic chemical filtering factory in the kidneys.
net force - the combination of all of the forces acting on an object.
neutral - a particle, object, or system that lacks a net charge. 8
neutron - electrically neutral particle found in the nucleus of an atom. 8
neutron star - rapidly spinning core of a massive star that remains after a supernova explosion.
new moon - phase of the moon when it is not visible in the sky.
Newton (N) - the SI unit for force.
Newton’s laws of motion - three rules describing how things move—an object will move with constant motion if no
net force is acting on it; an object that has an unbalanced force acting on it will accelerate in the direction of
the force; and forces occur in equal but opposite pairs.
niche - the unique position occupied by a particular species in terms of the area it inhabits and the function it performs
within the community. 11
nitrogen cycle - the continuous movement of nitrogen through Earth, its atmosphere, and the living things on Earth.
non-communicable - an illness that is not caused by a disease-causing organism; a non-infectious disease.
nonmetal - element that is a poor conductor of heat and electricity, has a dull surface, low melting point, is brittle,
breaks easily and forms negative ions.
non-point source - pollution that comes from many different sources, such as industries, homes, and farms. 15
nonrenewable resource - any resource that cannot be replaced by nature, such as fossil fuels and minerals. 5
nonvascular plant - plant lacking vascular tissue and that absorbs water and other dissolved substances directly
through its cell walls.
normal fault - crack formed when the hanging wall moves down relative to the foot wall.
normal force - upward force of the ground, perpendicular to the surface.
nostril - opening in the nose.
nova - star that suddenly increases in brightness.
nuclear energy - energy locked within the atomic nucleus; the energy released by a fission or fusion reaction.
nuclear family - parents and their children.
nuclear fission - splitting of an atomic nucleus into two smaller nuclei during which vast amounts of energy is released. 11
nuclear fusion - combining two lighter atomic nuclei to form heavier elements which produce large amounts of energy. 11
nuclear membrane - thin membrane that separates the nucleus from the protoplasm of the cell.
nucleic acid - large organic compound that stores information that helps the body make the proteins it needs.
nucleolus (plural-nucleoli) - cell structure located in the nucleus and made up of RNA and protein; may play
important role in making proteins for the cell.
nucleotide - the building blocks of DNA.
nucleus (plural-nuclei) - spherical organelle in eukaryotic cells that contains the genetic material and directs all the
activities of the cell; positively charged center of an atom containing most of the mass. 8
nutrient - useable portion of food; a substance that an organism needs to live.
objective - not influenced by emotions or personal prejudices, nor particular to one person.
observation - the process of obtaining information by using the senses.
ocean basin - a depression of the surface of Earth occupied by water. 8
ocean current - a stream of water that flows through the ocean in a regular pattern.
ocean-floor spreading - process in which the ocean floor on either side of a rift valley is pushed away by lava
erupting from the rift valley that forms new ocean floor.
oil - energy-rich organic compound made up of carbon, hydrogen and oxygen that is liquid at room temperature.
omnivore - animals that eat both plants and animals.
open cluster - a group of stars that are close together relative to surrounding stars.
oral groove - mouth-like indentation in a paramecium and other unicellular organisms.
orbit - path one object takes when moving around another object in space.
order - classification group between class and family.
ore - rock from which metals and other minerals can be removed in usable amounts.
organ - group of different tissues working together. 5
organelle - parts that make up a cell.
organic compound - compound that contains the element carbon.
organic rock - sedimentary rock built up from the remains of living things.
organism - entire living thing made up of one or more cells that carries out all the basic life functions. 5
organ system (system) - organs that work together to perform certain functions.
osmosis - the movement of water through a cell membrane.
outer core - liquid layer of the Earth surrounding the inner core.
ovary - the enlarged base of the pistil that holds the ovule.
ovule - the organ that produces and holds the eggs in a flower.
ozone (O3) - a gas molecule that consists of three oxygen atoms.
ozone layer - stratospheric layer with a high concentration of ozone; protects Earth by absorbing harmful ultraviolet radiation.
pacemaker - controls the pace at which the heart beats.
paleontologist - scientist who uses the remains or traces of long-dead organisms to form a picture of the Earth’s past.
pancreas - gland that produces pancreatic juice and insulin.
Pangaea - one large landmass of which all the continents were once a part according to the theory of continental drift.
parallax - apparent change in the position of an object due to the motion of an observer.
parallel - imaginary line used to measure latitude that runs east and west around the Earth.
paramecium (pl-paramecia) - microscopic, unicellular Protist that move by means of cilium (pl-cilia.)
parasite - organism that feeds on other living organisms often harming them in the process.
parasitism - a relationship between two species in which one species is harmed while the other benefits.
parent rock - a rock formation that is the source of soil.
particle - a very small piece of matter such as an atom, molecule, or ion.
particulates - tiny particles or droplets, such as dust, dirt, or pollen that are mixed in with air. 16
passive transport - the movement of materials through a membrane without any input of energy.
peer pressure - the process by which a person feels forced to do what others want them to do.
pelagic environment - in the ocean, the zone near the surface or at middle depths, beyond the sublittoral zone and
above the abyssal zone.
penumbra - outer area of a shadow cast by an object in space onto another object in space in which the light is only
pepsin - enzyme produced by the stomach that digests protein.
perigee - point of the moon’s orbit closest to the Earth.
periosteum - tough membrane surrounding a long bone.
peristalsis - powerful waves of muscle contractions that push the food through the digestive system.
permeability - the capability of a porous substance or membrane to allow a fluid or gas to enter it; the measure or
degree to which a substance can be penetrated by a liquid or gas. 11
permeable membrane - when materials will pass through a membrane.
petal - colorful blades that surround the inner parts of a flower.
petroleum - a liquid mixture of complex hydrocarbon compounds; used widely as a fuel source.
petrologist - scientist who studies rocks and their mineral composition.
pH - a symbol for the measure of the acidity or alkalinity of a solution. 11
phagocytosis - cellular eating.
phase - state in which matter can exist; solid, liquid, gas and plasma are the states of matter; the change in the sunlit
area of one celestial body as seen from another celestial body.
phenotype - the appearance or other observable characteristic of an organism resulting from the interaction of its
genetic makeup and its environment. 11
pheromone - powerful chemical produced by an animal to influence the behavior of another animal of the same
phloem - vascular tissue that carries dissolved food from the leaves to the rest of the plant.
phospholipids - a lipid that contains phosphorus and that is a structural component in cell membranes.
photoelectric effect - production of an electric current when photons of certain frequencies of light have enough
energy to knock electrons out of atoms of a metal plate.
photon -tiny packet of energy released by an electron.
photosphere - lowest layer of the sun’s atmosphere.
photosynthesis - process by which green plants make glucose for food by combining carbon dioxide and water by
using the sun’s energy. 5
photovoltaic cell - device that converts sunlight directly into electricity; solar cell.
phylogeny - evolutionary history of an organism.
phylum (plural-phyla) - second largest classification group; between kingdom and class.
physical change - change in which physical properties of a substance are altered, but the substance remains the same
kind of matter. 5
physical property - characteristic that distinguishes one type of matter from another and can be observed without
changing the identity of the substance.
physics - study of different forms of energy.
physiology - the study of the functions and activities of the body.
pinocytosis - cellular drinking.
pioneer community - first community of organisms to move into a new environment.
pioneer species - first plants to grow in new or disturbed environments and that change environmental conditions so
that other plant species can grow there.
pistil - the female reproductive part of a flower.
placenta - an organ that transports materials between a pregnant female mammal and the offspring developing inside her body.
planet - a large body in space that orbits a star and does not produce light of its own. 5
plankton - microscopic organisms that float or drift in large numbers in salt or fresh water; zooplankton—animal-like
and phytoplankton—plant-like. (planet comes from the word plankton)
Plantae (Plant) - a kingdom that is made up of multicellular eukaryotic cells that are usually green, have cell walls
made of cellulose, and use the sun’s energy to make sugar by photosynthesis.
plasma - phase in which matter is very high in energy and cannot be contained by the walls of ordinary matter, very
rare on Earth; yellowish liquid portion of the blood.
plate - broken sections of the Earth’s crust that are in constant motion. 17
platelet - part of a cell in the blood that aids in clotting.
plate tectonics - theory for the movement of the continents suggesting that the solid plates of the lithosphere are
moved slowly by convection currents originating deep inside the Earth whose movements cause seismic
activity along their borders. 8
platform - an area of a continent that is composed of flat-lying layers of sedimentary rock.
point-source - single, identifiable pollution source.
polar easterlies - prevailing winds that blow from east to west between 60o and 90o latitude in both hemispheres.
Polaris - north star.
pollen - tiny multicellular grains that contain the undeveloped sperm cells of a plant.
pollination - a transfer of pollen to an egg-producing organ.
pollution - introduction of harmful waste products, chemicals, and substances into the environment; may occur
naturally or as a result of human activities. 5
population - a group of organisms of the same species living in a specific geographical area. 5
population density - a measure of the number of organisms that live in a given area.
porphyry - igneous rock whose cooling rate changed and thus has two or more different-sized crystals.
potential energy - the energy an object has because of its position, shape or condition; stored energy. 5, 8
power - measures the rate at which work is done in a certain period of time; unit is the watt (W).
precipitation - water falling from clouds, including rain, snow, sleet, and hail.
precision - the degree of accuracy or exactness of a measurement or tool. 11
predator - an organism that preys on and consumes animals; usually an animal. 5
pressure - the force exerted per unit area. 8
prevailing winds - winds that blow mainly from one direction during a given period.
prey - an organism caught or hunted for food by another organism. 5
primary succession - ecological succession that begins in a place that does not have soil.
prime meridian - imaginary line at 0o longitude that runs north and south through Greenwich, England.
principle of uniformitarianism - idea that states that the processes that act on the Earth’s surface today are the same
as the processes that have acted on the Earth’s surface in the past.
prism - a piece of glass with polished plane surfaces that disperses a beam of white light into its component colors. 8
producer - an organism that makes its own food from the environment; usually a green plant. (autotroph) 5
product - a substance or compound resulting from a chemical reaction. 11
prokaryotic cell (prokaryotes) - the simplest type of cell with no true nucleus to surround the genetic materials.
(kingdoms: Archaea and Bacteria)
prominence - solar storm in the form of huge bright arches or loops of gas from the sun.
property - quality or characteristic that describes an object.
protein - organic compound made up of carbon, hydrogen, oxygen, nitrogen and sometimes sulfur and phosphorus,
necessary for the growth and repair of body structures; a biological macromolecule composed of one or more
chains of amino acids. 11
Protista (Protist) - a kingdom made up of unicellular eukaryotic cells. 5
proton - positively charged particle found in the nucleus of an atom. 8
protoplanet - early stage of a planet.
protoplasm - all the living material found in both plant and animal cells.
protostar - new star.
protozoan (plural-protozoa) - unicellular animal-like protists.
pseudopod - ―false foot‖ in amoeba.
ptyalin - enzyme in saliva that breaks down some starches into sugars.
puberty - the period during which the physical and emotional changes which lead to adulthood take place; time frame
in which the reproductive organs become functional.
pulley - surface, such as a wheel, that redirects force using a rope; a simple machine that allows you to pull down to
lift a weight. 5
pulsar - neutron star emitting radio waves.
Punnett square - a graphic checkboard used to determine results from a particular genetic cross. 8
pure substance - substance that contains only one kind of molecule.
P wave - a seismic wave that causes particles of rock to move in a back-and-forth direction.
qualitative - description that does not use measurement or numbers.
quantitative - description that uses measurement or numbers.
quark - particle that makes up all subatomic nuclear particles. 18
quasar - quasi-stellar radio source that is probably an early stage in the formation of a galaxy.
radar - is an electronic system used to locate and identify distant objects.
radiant energy - visible and invisible energy from the sun that moves in waves, such as light and heat.
radiation - transfer of heat energy through space; emission of energy in the form of rays or waves. 8
radius - is a line segment connecting the center of the circle to a point on the circumference.
rain shadow - an area on the downwind side of a mountain that gets less precipitation than the side that faces the wind.
rarefaction - a place where particles are spaced far apart.
rate - ratio of two measurements with different units—for example, speed, measured in kilometers per hour (km/h);
fraction in which the numerator and denominator have different units.
rate of reaction - the speed at which reactants are consumed and products are produced in a given reaction. 11
reactant - any substance or molecule that participates in a chemical reaction. 11
recessive - an allele for a trait that will be masked unless the organism is homozygous for this trait. 8
recycling - the process of recovering valuable or useful materials from waste or scrap.
red blood cell - cell that carries oxygen through the body.
red shift - shift of light from moving stars toward the red end of the spectrum.
reflection (reflect) - occurs when a wave (light, sound, or heat) strikes an object or surface and bounces off. 5
refraction - bending of a wave as it moves from one medium into another of different density. 5
relative humidity - the comparison of the amount of water vapor in air with the maximum amount of water vapor that
can be present in air at that temperature.
remote sensing - way of collecting information about Earth from a distance–for example, by satellites and sonar.
renewable resource - any resource that can be replaced or restored, as it is used, by natural processes, such as wind,
water, soil and living resources in a reasonable amount of time. 5
reproducible - a result that is the same no matter who produces it or where or when it is produced.
reproduction - process by which living things give rise to the same type of living thing.
reptile - a cold-blooded vertebrate that has skin covered with scales or horny plates and lungs.
resistance force (Fr) - force a machine must overcome.
resource - any material that can be used to satisfy a need. 5
respiration (cellular respiration) - process by which living things take in oxygen and use it to produce energy.
respiratory system - body system responsible for getting oxygen into the body.
response - some action or movement of the organism brought on by a signal.
responsibility - a duty or obligation.
retrograde motion - rotation of a planet on its axis from east to west, which is the reverse motion of most planets.
retrovirus - a microscopic organism that can cause tumors and diseases in animals and people; they contain RNA and
use it to make DNA which is the opposite of most viruses.
reverse fault - crack formed when the hanging wall moves up relative to the foot wall.
revolution - movement of a planet in which it makes one complete trip around the sun; the motion of a body that
travels around another body in space.
ribonucleic acid (RNA) - nucleic acid that ―reads‖ the genetic information carried by DNA and guides the
protein-making process; a single-stranded nucleic acid consisting of a phosphate group and one of four
nitrogenous bases that encodes information needed to synthesize proteins. 11
ribosome - grain-like body made up of RNA and attached to the inner surface of an endoplasmic passageway; a
protein- making site of the cell.
Richter scale - measure of the amount of energy an earthquake releases.
rift valley - formed when the block of land between two normal faults slides downward; a long, narrow valley in
Earth’s crust where two continental plates are separating between two faults. 11
rift zone - an area of deep cracks that forms between two tectonic plates that are pulling away from each other.
rille - valley on the moon.
Ring of Fire - major earthquake and volcano zone that extends nearly all the way around the edge of the Pacific Ocean.
risky behavior - behavior that is more likely to allow exposure to infectious agents.
Robinson projection - map projection that has accurate continent shapes and accurate land areas; has parallel latitude
lines and curved longitude lines.
robot - a machine that works automatically or by remote control.
rock - is a naturally occurring, solid material made of one or more minerals or organic matter.
rock cycle - continuous changing of rocks from one kind to another.
rotation - movement of a planet in which it makes one complete spin on its axis.
salinity - a measure of the amount of dissolved salts in a given amount of liquid. 19
salinization - the accumulation of salts in soil.
saprophyte - organism that feeds on dead things.
satellite - natural or artificial object in space orbiting another object in space.
saturation - a condition of the atmosphere in which the rates of evaporation and condensation are equal.
scale - one of the thin, small, overlapping plates that cover most fish and reptiles and some other animals.
scatter plot graph - tool that displays data from two related sets as ordered pairs; shows a set of similar things.
science - process of trying to understand the world around us; the knowledge obtained by observing natural events and
conditions in order to discover facts and formulate laws or principals that can be verified or tested.
scientific inquiry - may include one or more experiments or investigations.
scientific literacy - the understanding of the methods of scientific inquiry, the scope of scientific knowledge, and the
role of science in society.
scientific method - basic steps that scientists follow in uncovering facts and solving scientific problems; a plan of
inquiry that uses science process skills as tools to gather, organize, analyze, and communicate information. 5
scientific name - a combination of the genus name and the species name of a living thing.
screw - a type of simple machine that consists of an inclined plane wrapped around a cylinder. 8
sea breezes - daily movements of air created when cooler, denser air moving inland from the ocean forces warm air
over the land to rise.
sea-floor spreading - the process by which new oceanic lithosphere (sea-floor) forms as magma rises to Earth’s
surface and solidifies at a mid-ocean ridge.
seamont - a submerged mountain on the ocean floor that is at least 1000 m high and that has a volcanic origin.
seasons - periods of the year associated with specific weather conditions.
sea stack - column of resistant rock left standing after waves eroded a sea cliff.
secondary succession - ecological succession that begins in a place that already has soil and was once the home of
second law of thermodynamics - law that states all natural processes proceed in a preferred direction. (EX - heat
flows from high temperature regions to low temperature regions) 11
sediment - small pieces of rocks, shells or the remains of plants and animals that have been carried along and
deposited by wind, water or ice.
sedimentary rock - type of rock formed in layers of sediment that overlay and squeeze together or are chemically
seed - a plant embryo that is enclosed in a protective coating and has its own source of nutrients.
seismic wave - a wave of energy that travels through the Earth and away from an earthquake in all directions.
seismograph - instrument used to detect and measure shock waves from an earthquake.
seismology - the study of earthquakes.
self-esteem - pride in oneself; self-respect.
semi-permeable membrane - when selected or only some materials will pass through a membrane.
sepal - leaf-like structures at the base of a flower.
septum - thick wall of tissue that separates the heart into right and left sides.
serendipity - the knack for making fortunate discoveries by accident. (Mark Twain)
sessile - the quality of being attached to one spot; not free-moving.
sexual reproduction - formation of an organism from the uniting of two different sex cells; reproduction involving
the union of gametes producing an offspring with traits from both parents. 8
shearing - type of stress that cause a rock to twist or tear apart by pushing on the rock in two opposite directions.
SI (International System of Units) - metric system; was designed to give a worldwide standard of physical measurement
for science, industry, and commerce and uses units such as the meter, cubic meter, kilogram, and Kelvin.
sill - sheet-like mass of igneous rock.
simple machine - machine that works with only one motion; (an inclined plane, lever, wheel and axle, pulley, wedge, and screw.)
single-parent family - a single mother or father and their children.
skeletal muscle - voluntary tissue made up of striped fibers; responsible for voluntary movement.
skepticism (skeptic, skeptical) - a habit of mind in which a person questions the validity of accepted ideas.
skin - outer covering of the body.
sleet - small pellets of ice that form when rain passes through a layer of cold air and freezes before hitting the ground.
slip face - side of a sand dune with a steep slope.
small intestine - organ in the digestive system in which food is absorbed.
smog - the combination of smoke and fog; a type of air pollution that occurs when sunlight causes unburnt fuels,
fumes, and other gases to react chemically, often seen as a brownish haze.
smooth muscle - nonstriped muscle tissue that is not voluntary; responsible for involuntary movement. 20
social behaviors - interactions among organisms of the same species, including courtship and mating, caring for the
young, and getting food.
society - group of animals of the same species that live and work together in the same way and in which each member
has a certain job.
soil - a loose mixture of rock fragments, organic material, water, and air that can support the growth of vegetation.
soil conservation - a method to maintain the fertility of the soil by protecting the soil from erosion and nutrient loss.
soil structure - the arrangement of soil particles.
soil texture - the soil quality that is based on the proportions of soil particles.
solar cell - a device that converts the energy of sunlight into electrical energy.
solar eclipse - eclipse that occurs when the new moon comes directly between the sun and Earth.
solar energy - energy from the sun that is nonpolluting, renewable, and abundant but is available only when the sun is shining.
solar flare - explosive increase in brightness near sunspots on the sun’s surface that releases great amounts of energy into space.
solar mass - the quantity equal to the mass of the sun. 11
solar system - star/sun—planets and all the other objects that orbit it. 5
solar wind - continuous stream of high-energy particles released into space in all directions from the sun’s corona.
solid - phase in which matter has a definite shape and volume. 5
solstice - occurs twice yearly when the sun is directly over the northernmost or southernmost edges of the tropics; in
the Northern Hemisphere, the winter solstice (December 21 or 22) has the fewest daylight hours and the
summer solstice (June 21 or 22) has the most daylight hours.
solubility - the ability or tendency of one substance to dissolve in another at a given temperature and pressure. 11
solution - a mixture of two or more substances uniformly dispersed throughout a single phase. 5
specialization - the specific organization of a cell and its structure that allows it to perform a specific function.
species - group of organisms that are able to interbreed or produce young; a group of organisms of common ancestry
able to reproduce only among themselves and usually geographically distinct. 11
spectroscope - instrument that separates light into its various colors and wavelengths. 8
spectrum - band of colors produced by the breaking up of white light.
speed - amount of distance traveled divided by time taken; the time-rate at which any physical process takes place. 8
spiral galaxy - pinwheel-shaped galaxy that has huge spiral arms.
spirillum (plural-spirilla) - spiral-shaped bacterium.
spit - long, underwater pile of sand connected to a curving shoreline.
sponge - a simple multicellular invertebrate animal that lives attached to one place and filters food from water.
spontaneous generation - theory that states that life can spring from nonliving matter.
spore - a single reproductive cell that can grow into a multicellular organism.
sprain - tearing or twisting of a ligament or muscle.
spring tide - high tide that is higher than usual; occurs twice monthly at the new and full phases of the moon. 8
stamen - the male reproductive part of a flower.
star - a large, gaseous, self-luminous body held together by gravity and powered by thermonuclear reactions. 5
state (of matter) - phase in which matter can exist; solid, liquid, gas and plasma are the states of matter.
step family - formed when parents remarry.
stigma - the sticky top part of a pistil.
stimulus (plural-stimuli) - signal to which an organism reacts; a condition that produces a reaction. 11
stock - intrusion similar to a batholith that has an exposed area of less than 100 square km.
stoma (pl-stomata) -a tiny opening in plant leaves through which water vapor, oxygen and carbon dioxide pass.
stomach - organ in which foods are physically and chemically digested.
storm surge - a rapid rise in water level in a coastal area that occurs when a hurricane pushed a huge mass of ocean
water, often leading to flooding and widespread destruction.
strata - layers of sedimentary rocks.
stratosphere - the layer of the atmosphere that is above the troposphere and in which temperature increases as altitude increases.
streak - color of a mineral in powder form.
stress - force that pushes or pulls rocks.
structure - the arrangement of parts in an organism. (part; what it is; anatomy)
subatomic particle - particle that is smaller than an atom.
subduction - process in which the ocean floor plunges back into the interior of the Earth through a trench.
subjective - opinions and experiences particular to one person.
sublimation - process in which the surface particles of a solid change directly into gas.
subscript - number placed to the lower right of a chemical symbol to indicate the number of atoms 21
of the element in the compound.
subsidence - the sinking of regions of the Earth’s crust to lower elevations.
substance - matter of a particular type; (elements, compounds, and mixtures.)
succession - the progressive replacement, on a single site, of one type of community by another. 11
sun - the closest star to Earth and the center of our solar system. 5
sunspot - solar storm that appears as dark patches on the sun’s face because it is cooler than the surrounding regions.
supergiant star - star with a diameter up to 1000 times the diameter of the sun.
supernova - exploding star.
surface current - a horizontal movement of ocean water that is caused by wind and that occurs at or near the ocean’s surface.
sustainable - the managing of certain natural resources so that they are not harmed or used up.
S wave - a seismic wave that causes particles of rock to move in a side-to-side direction.
symbiosis - the positive interaction between individuals from two different species that live closely together.
symptoms - the signs that indicate that a disease is present.
syncline - downward fold in a rock layer.
syndrome - a group of signs and symptoms that occur together and characterize a particular abnormality.
system (organ system) - group of organs that work together to perform certain functions; a set of objects, organisms,
or different parts acting to form a whole. 5
table - tool used to display information in rows and columns so that it is easier to read and understand. (EX - data table)
taiga - cold region of cone-bearing evergreen trees that lies just below the tundra and is the Earth’s largest terrestrial biome.
taxonomy - science of classification.
technology - use of knowledge gained through scientific thinking and problem solving to make products or tools people can use.
tectonic plate - a block of lithosphere that consists of the crust and the rigid, outermost part of the mantle.
temperate deciduous forest - biome that lies at latitudes below about 50o in both the northern and southern
hemispheres, usually has four distinct seasons, and supports a wide variety of plants and animals.
temperature - a measure of how hot or cold something is; a measure of the average kinetic energy of the particles in an object.
tendon - a tough, elastic connective tissue attaching a muscle to a bone.
tension - type of stress that pulls rock apart; stress that occurs when forces act to stretch an object.
tentacle - a long, slender, flexible extension of the body of certain animals that are used to touch, move, and hold.
terminal moraine - ridge or rounded hill of till deposited at the front end of a glacier.
territory - area that an animal defends from other members of the same species and that contains food, shelter, and
testosterone - hormone produced by testes; responsible for the development and growth of secondary sex
characteristics in males.
texture - the quality of a rock that is based on the sizes, shapes, and position of the rocks grains.
theory - a set of ideas that explains related observations and is supported by a large body of evidence acquired through
theory of continental drift - idea that says that all of the present-day continents were joined together in one large
landmass that split apart and the continents drifted to their present positions.
theory of plate tectonics - idea that combines the ideas of continental drift and ocean-floor spreading to explain the
formation of the earth’s crust and its movements.
thermal energy - internal energy found by adding the kinetic energy of particles making up a substance. 8
thermometer - an instrument that measures and indicates temperature.
thermophile - Archaea that survive in high heat and acid.
thermosphere - the uppermost layer of the atmosphere, in which temperature increases as altitude increases.
thrust fault - crack formed when compression causes the hanging wall to slide over the foot wall.
thunder - the sound caused by the rapid expansion of air along an electrical strike.
thunder storm - a usually brief, heavy storm that consists of rain, strong winds, lightning and thunder.
tidal energy - energy produced by the rise and fall of the tides.
tidal range - the difference in levels of ocean water at high tide and low tide.
tide - regular rising and falling of the oceans caused by the moon’s gravitational pull on the Earth.
till - unsorted rock material deposited by a glacier as it melts.
time zone - north-south section of the earth in which all clocks show the same time.
tissue - group of cells similar in structure and joined together to perform a common function; four basic types of tissue
are muscle, connective, nerve, and epidermal. 5
topographic map - flat map showing contour lines that represent the height and depth of features on the Earth’s
topography - the surface, shape, and composition of a land area. 5 22
tornado - a destructive, rotating column of air that has very high wind speeds and that may be visible as a funnel-shaped
toxic - poisonous.
toxin - poison.
trachea - windpipe.
trade winds - prevailing winds that blow from east to west from 30o latitude to the equator in both hemispheres.
trait - is a characteristic or behavior that can be used to tell two species apart.
transform boundary - transform fault where two plates grind and slide past one another horizontally.
transfusion - process of transferring blood from one body to another.
transmitted - in the context of disease, passed from one individual to another.
transpiration - loss of water vapor through the stomata of a leaf.
transverse wave - wave in which the wave energy is at right angles to the electric and magnetic fields generated by
moving photons of energy.
trench - deep V-shaped valley along the ocean floor.
trial - one repetition of a procedure.
tropical rain forest - hot, wet, equatorial biome that contains the largest number of species.
tropical storm - a low-pressure system that starts in the tropics with winds of at least 65 km/hr but less than 120 km/hr.
tropism - response of a plant to an outside stimulus such as gravity or light; the motion of an organism or part of an
organism toward or away from an external stimulus. 8
troposphere - layer of the atmosphere closest to the ground; contains 75% of the atmospheric gases, dust, ice, and
liquid water and is where weather, smog, and clouds occur.
trough - the lowest point of a wave. 8
tsunami - giant sea wave caused by an underwater earthquake.
tundra - cold, dry, treeless biome located at latitudes surrounding the north pole and that has winters six to nine months long.
ultraviolet radiation (UV) - type of energy that comes to Earth from the sun and is mostly absorbed by the ozone
layer; can cause cancer and other health problems in many types of plants and animals.
umbra - inner area of a shadow cast by one object in space onto another object in space in which the light is
completely blocked out.
uncomformity - eroded rock surface pushed up from deeper within the Earth that is much older than the new rock
layers above it.
unfoliated rock - texture of some metamorphic rocks in which crystals are not arranged in bands and do not break in layers.
unicellular - having one cell.
universe - the total sum of all matter and energy that exists. 5
uplift - the rising of regions of the Earth’s crust to higher elevations.
urban - a city environment.
urban heat island - the warmer body of air over a city.
urea - nitrogenous waste formed in the liver.
ureter - tube that conducts urine to the urinary bladder.
urethra - tube through which urine passes out of the body.
urinary bladder - muscular sac that stores urine.
vaccination - immunization against specific diseases by injection or by mouth so that active immunity is developed.
vaccine - preparation usually composed of dead or weakened viruses that help the body to develop active immunity
against a disease.
vacuole - large, round sac floating in the cytoplasm of a cell in which water, food, enzymes and other materials are stored.
valley glacier - long, narrow sheets of ice that moves very slowly down a steep mountain valley.
value - that which is desirable or worthy of esteem for its own sake.
Van Allen radiation belt - two doughnut-shaped regions of particles surrounding the Earth that trap radiation from the sun.
vaporization - change of a liquid to a gas.
variable - factor being tested in an experiment; an event, condition, or factor that can be changed or controlled in order
to study or test a hypothesis in a scientific experiment. 8
variable star - star that regularly varies in brightness.
vascular plant - plant with specialized tissue that moves water, food, and dissolved substances to cells throughout the plant.
vascular system - long tube-like tissues in plants through which water and nutrients move from one part of the plant to another.
vector - a physical quantity with both a magnitude and direction. 11
vein - blood vessel that carries blood from the body back to the heart.
vegetative reproduction - the growth of new plants from a part of a parent plant.
velocity - the time-rate at which a body changes its position vector; displacement divided by the time of travel; 23
quantity whose magnitude is expressed in units of distance over time; 8, 11 the speed of an object in a particular direction.
vent - opening in a volcano from which lava erupts.
ventricle - lower chamber of the heart.
vertebra (plural-vertebrae) - bone in the vertebral column.
vertebrate - animal with a backbone; only about 3 percent of animals are vertebrates.
vibration - a repetitive movement around an equilibrium point. 8
villus (plural-villi) - hair-like projection in the small intestine that absorbs digested food in the bloodstream.
virus - microscopic, parasitic particle composed of nucleic acid and protein that can be reproduced only in a living
cell; a noncellular, disease-causing particle that uses the genetic material from its host to reproduce. 8
viscosity - is the resistance of a liquid to flow.
vocal cord - tissue in the larynx that vibrates with the passage of air to form sounds.
volcano - a vent or fissure in the Earth’s surface where lava reaches the Earth’s surface. 5
volume - amount of space an object takes up; 3-D; the loudness of a sound or signal. 5
waning-crescent - phase of the moon between one-half and new moon when the lighted area of the moon appears to
waning-gibbous - phase of the moon between full and one-half when the lighted area of the moon appears to grow smaller.
warm-blooded - able to maintain a constant body temperature.
water cycle - the continuous movement of water between Earth’s surface and the atmosphere through evaporation,
condensation, and precipitation. 5
wave - transfer of energy or movement.
wavelength - distance between a point on one wave and an identical point on the next wave measured from crest to
crest or trough to trough; in compressional waves, is measured from one compression or rarefaction to the next. 8
waxing-crescent - phase of the moon between the new moon and one-half moon when the lighted area of the moon
appears to grow larger.
waxing-gibbous - phase of the moon between one-half and full when the lighted area of the moon appears to grow larger.
weather - the condition of Earth’s atmosphere at a particular time and place.
weathering - process by which surface rocks and other materials are broken down by wind, water, and ice into soil,
sand, and other materials. 5
wedge - moving inclined plane with one or two sloping sides; a type of simple machine that consists of an inclined
plane used to separate two objects; 8 used to cut, split, or pierce objects or to hold objects together.
weight - measure of the force of attraction between objects due to gravity.
westerlies - prevailing winds that blow from west to east between 30o and 60o latitude in both hemispheres.
wheel and axle - simple machine made from two rigidly attached wheels that rotate together; consists of a rod driven
through the center of a cylinder that is allowed to rotate freely, yielding a mechanical advantage equal to the
cylinder’s diameter. 5, 8
white blood cell - blood cell that acts as a defense system against disease.
white dwarf - small, very dense star of carbon that results when a star of low mass, like our sun, collapses.
wind - horizontal movement of air caused by different air pressure.
wind power - the use of a windmill to drive an electric generator.
work - occurs when a force produces movement parallel to the direction in which the force is applied; unit is the joule (J).
xenozoonoses - potentially, deadly viruses that are found in animals and can be transplanted to humans
through nonhuman tissue transplants.
x-ray (x ray, X-ray, X ray) - electromagnetic radiation having a wavelength shorter than that of ultraviolet light but
longer than that of a gamma ray and having a correspondingly high energy.
xylem - vascular tissue that carries water and dissolved minerals from the soil to the leaves.
zoology - study of animals.
List any words that could be added to our science glossary: