8th Grade Science Mid-Term Vocabulary

galaxy

• a system of stars and associated matter held together by gravitational attraction

• a large body of ice and dust in space

• a cluster of planets orbiting a star

• a type of celestial event involving supernovae

Subduction Zone

• The region where oceanic plates sink down into the asthenosphere.

• A place where tectonic plates slide past each other.

• An area where continental plates collide and create mountains.

• A zone where oceanic plates are formed at mid-ocean ridges.

Frequency

• the number of times a wave passes a certain point in a given amount of time

• the speed at which a wave travels through a medium

• the distance between two consecutive peaks of a wave

• the total energy carried by a wave

chemical change

• a change in matter that produces a new substance

• a physical alteration without changing the substance

• a process that only involves temperature changes

• a reaction that can be easily reversed

Newton's 1st Law

• the tendency of an object to resist change in motion unless acted upon by an outside net force

• an object in motion stays in motion unless acted upon by a force

• the force acting on an object is equal to the mass of the object times its acceleration

• for every action, there is an equal and opposite reaction

Transform Boundary

• A plate boundary where two plates move past each other in opposite directions

• A plate boundary where two plates collide and create mountains

• A plate boundary where two plates move away from each other

• A plate boundary that causes volcanic activity

homogeneous mixture

• A mixture in which substances are evenly distributed throughout the mixture, uniform

• A mixture where the components are easily distinguishable

• A mixture that contains only one type of substance

• A mixture that has a variable composition

Continental Drift Theory

• A theory that suggests continents are fixed in their positions

• A theory proposed by Alfred Wegener that the continents have not always been in their present locations but have moved there over millions of years

• A hypothesis that explains the formation of mountains due to tectonic plates

• A concept that states oceans are expanding and continents are sinking

Pangaea

• The name of the single landmass that broke apart 200 million years ago and gave rise to today's continents

• A type of ancient dinosaur

• A geological term for volcanic activity

• The name of the first human civilization

base

• a compound that produces hydroxide ions in solution

• a compound that produces hydrogen ions in solution

• a compound that has a sour taste

• a compound that turns red litmus paper blue