the four basic components of our planet: atmosphere, hydrosphere, geosphere, and biosphere.

systematic approach to exploring and explaining how the natural world operates. It is an interactive process of inquiry that involves acquiring data, formulating questions, devising hypotheses, making predictions from hypothesis, and carrying out observations to support or refute hypotheses.

system in which the transfers of matter or energy in and out are approximately equal; as a result, the system appears not to change.

age, in years; how geologists know how long ago event have occurred.

a distinctive part of the upper mantle directly below the lithosphere (mostly solid, but pliable (like putty) and can flow under pressure) has also been called the upper mantle’s low velocity zone.

the crust that makes up Earth’s landmasses and their shallowly submerged edges.

interior of Earth which contains two parts, the solid inner core and the liquid outer core. (solid=1.7% Earth’s mass, liquid=30.8% Earth’s mass) Both are made of mostly iron and nickel.

interval in which the geologic time scale divides Earth’s history (four parts). 

when a fossil changes from lower to upper parts of a sequence or form one sequence to another in regular ways.

scale used for periods of time long enough to allow us to understand Earth’s history.

scale that summarizes Earth’s geologic history as determined from studies of rocks, fossils, and other relative ages.

a rock, typical of continental crust, containing calcium, sodium, potassium, aluminum, silicon, and oxygen.

glaciers that coalesce and cover greater than square 50,000 square kilometers.

times when a large number of species become extinct. 

process which Darwin and Wallace’s sought to explain of how life changed overtime.

the layer above the troposphere. Temperatures increase upward through the stratosphere.

the outer atmospheric layer, above the mesosphere.

the changes in location of the magnetic poles over time.

part of a continent, especially the submerged part (the continental rise, slope, and shelf), adjacent to oceanic crust.

India, Australia, South Africa, and South America used to have connecting “land-bridges” (fingers of land). The five continents and their land-bridges were once called this.

magnetic fields leave a pattern on the sea floor that resembles strips.

when the magnetic field is reversed (pointing south instead of north)

raised seafloor (similar to seams on a baseball)

place where crust is extending and breaking apart; along rift hot material in mantle rises and overlying crust thins and weakens as it is warmed and stretched. 

movement of newly formed oceanic crust away from mid-ocean ridges.

when blocks slide horizontally past each other.

low angle reverse fault; surface along where blocks of rock move has low inclination.