Download STAAR Science Vocabulary 2016

Science STAAR Vocabulary-8th Grade
Atom—smallest particle of an element; made of electrons, protons, and neutrons
Atomic Mass—mass of atom; equal to number of protons and neutrons in the atom
Balanced Equation—represents a chemical equation; both sides contain equal numbers of atoms
of each element
N2 + 3H2
2NH3
Chemical Formula—shorthand notation that uses chemical symbols and numbers as subscripts to
represent type and number of atoms present
H2O
Electrical Charge—electrons are negatively charged; protons are positively charged; the
numbers of protons and electrons in the atom determine the charge of the atom. The proton
determines the charge of the nucleus because the neutron is neutral and has no charge.
Electron—negatively charged, subatomic particle found in electron cloud outside the nucleus; EElectron Cloud—area surrounding the nucleus of the atom where the electrons are found
Neutron—subatomic particle in the nucleus of the atom that has no charge; N0
Nucleus—very dense, positively charged region at the center of the atom; P+ and N0
Proton—positively charged particle in the nucleus of the atom; P+
Atomic Number—number of protons in the nucleus; equals # of electrons, too.
Energy Level—rings of electrons outside the nucleus; found in electron cloud
Valence Electrons—electrons in the outermost energy level that influences how an element will
react with other substances
Reactivity—influenced by number of valence electrons; Group 8 is non-reactive while Group 1
is highly reactive
Metal—solid, shiny, malleable and a good conductor; most elements are metals
Nonmetal—usually a gas or brittle solid, not shiny, not malleable and not a good conductor
Metalloids—elements that have properties of both metals and nonmetals; often called
semiconductors
Element—pure substance; cannot be separated into simpler substances; made of the same atom
Groups—columns on the Periodic Table; arrange elements by number of valence electrons
Periods—rows in the Periodic Table; classify the elements by the number of electron shells
Chemical Reaction—process by which one or more substances change to produce one or more
different substances
Coefficient—number placed in front of a chemical formula; 2H3
Law of Conservation of Matter—mass of all reactants must equal mass of all products
Reactants—substance that takes part in and undergoes change during a chemical reaction; in
front of the arrow
2NH3
N + 3H
2
2
Product—substance produced during a chemical reaction; comes after the arrow
N2 + 3H2
2NH3
Endothermic—process that absorbs heat; heat goes IN
Exothermic—process that releases heat; heat EXITS
Precipitate—a solid that is deposited from a solution
Motion—change in an object’s position
Friction—force that opposes motion
Force—a push or pull that can change the motion of an object;
Net Force—sum of ALL the forces acting on an object
Balanced Forces—forces acting on an object that combined do not change the movement of the
object; NO MOTION; forces are equal
Unbalanced Forces—forces acting on an object that cause change in the motion of the object;
MOTION; forces are not equal
Speed—rate of change over time; s = d/t
Velocity—speed and direction; 55 mph East
Acceleration—the rate of change in an object’s speed.
Inertia—tendency of an object to remain still or continue moving, unless force is applied
Newton’s Law of Inertia—an object at rest stays at rest and an object in motion stays in motion
unless acted on by an outside force; also known as Newton’s First Law
Newton’s Law of Force and Acceleration—acceleration of an object depends on the object’s
mass and magnitude of the force acting upon it; also known as Newton’s
Second Law; F = m x a
Newton’s Law of Action-Reaction—for every action there is an equal and opposite reaction; also
known as Newton’s Third Law of Motion
Axis—imaginary line through the Earth that extends from the North Pole to the South Pole; the
center of Earth’s rotation
Orbit—curved path of an object around a point in space
Revolution—moving in an elliptical path around a point in space; Earth revolves around the Sun
Rotation—spin on an axis; Earth’s spinning on its axis causes day and night
Tilt—the slant of Earth’s axis; 23.5o; North Pole always point to the North Star, Polaris
Seasons—four divisions of the year based on changes in temperature due to varied amounts of
Sunlight; caused by the tilt of the Earth on its axis
New Moon—phase when Moon is between the Sun and the Earth; NONE of the illuminated
portion is facing the Earth
Crescent Moon—shape of the Moon that is less than a quarter Moon
First Quarter Moon—half of the disk is illuminated; the cycle is in the waxing phase
Gibbous Moon—shape of the Moon that is greater than a quarter Moon, but not full
Full Moon—entire disk illuminated
Last or Third Quarter Moon—half of the disk is illuminated; the cycle is in the waning phase
Waning—weakening or getting smaller
Waxing—growing or getting larger
Ocean Tide—daily changes in the level of ocean water; caused by Moon’s gravitational pull
Neap Tide—tides with the smallest daily tidal range; Sun, Earth, Moon form a 90 degree angle
Spring Tide—tides with the largest daily tidal range; Sun, Earth and Moon are in a line
Galaxy—large grouping of stars in space
Elliptical Galaxy—galaxy with long, oval shape, bright center
Irregular Shaped Galaxy—galaxy with no specific shape
Spiral Galaxy—galaxy with a bulge in the center with distinct long arms winding around a
center; our Milky Way Galaxy
Star—self-luminous celestial body; most made of hydrogen and helium
Hertzprung-Russell Diagram—diagram of stars’ surface temperature (color) and
(H-R)
luminosity (brightness)
Luminosity—intensity of light from a celestial body; brightness
Main Sequence—stable stars, such as the Sun; diagonal belt on the H-R Diagram
Black Hole—remains of a star that collapsed under its own gravity; light cannot escape
Nebula—cloud of gas and dust in space; location of star formation
Supernova—the death of a large star by explosion
Electromagnetic Spectrum—grouping of electromagnetic radiation from radio waves to gamma
rays; all can travel through space; do not need a medium to travel
Light Year—unit of length; distance light travels in one year; 9.5 trillion km
Continental Drift—theory that continents were once connected but have drifted apart
Theory of Plate Tectonics—lithosphere is divided into tectonic plates that move slowly on the
asthenosphere
Convergent Boundary—plates collide; can create mountains, trenches, volcanic islands
Subduction—denser plate is pushed under less dense when they plates collide; oceanic-oceanic
and continental-oceanic boundaries
Divergent Boundary—when two plates move away from each other; can create rift valleys or
mid-ocean ridges
Transform Boundary—two plates slide past each other; creates earthquakes
Topographic Maps—map showing changes in Earth’s elevation; contour lines show elevation
Convection Currents—heat transfer caused by the rising of hot, less dense fluids and the sinking
of colder, more dense fluids
Ocean Currents—directional movement of ocean water; surface currents result from winds; deep
currents result from density variations due to temperature and salinity differences
Coriolis Effect—deflection of moving air; result of Earth’s rotation
Cold Front—border between advancing mass of cold, dense air and a receding mass of warm air
Warm Front—border between advancing mass of warm, moist air & a receding mass of cool air
Humidity—amount of water vapor/moisture in the air
Autotroph—organism that makes its food, such as plants
Heterotroph—organism that must use other organisms for food, such as animals
Carnivore—an animal that eats other animals
Herbivore—an organism that eats only plants
Omnivore—an organism that consumes both plants and animals
Consumer—organism that feeds on other organisms in a food chain
Decomposer—organisms such as bacteria & fungi; break down the remains of dead organisms
Host—an organism upon or within which another organism live; leech on your leg
Parasite—organism that survives on a host organism and causes harm to the host
Predator—an animal that lives by killing and eating other animals
Prey—an animal that is eaten by another animal
Producer—organism that makes its food using energy from light/the Sun or chemical compounds
Abiotic Factors—non-living factors that affect the ecosystem; light, temperature, shelter, water
Biotic Factors—factors that are living or produced by living things; animals, plants, relationships
Competition—when more than one individual or population relies on the same limited resources
Adaptation—process by which an organism/population becomes better suited for its environment
Invasive Species—a species that enters an area from somewhere else and disrupts the native
ecosystem