Science OGT Study Guide

The Big Bang Theory
Theory that the earth was created in one giant explosion billons of years ago, and is constantly expanding today from its location.
Red Shift
displacement of a star's light toward the red end of the spectrum, caused by an increase in distance from the star and the observer
Grocentric Theory
earth is the center of the solar system. THIS IS WRONG
Heliocentric Theory
copernicus proposed that the sun is the center of the system. THIS IS CORRECT. Eart and other planets orbit the sun.
a cloud of dust and gas that are pulled together by gravity
Law of Universal Gravitation
Between any two object there is an attraction (gravity) that is proportional to the mass of the objects and the distances between them.
Relative Term Scale
determine age by the sequences of rocks
absolute dating
actual dates and ages
plate tectonics
theory that Earth's crust is broken up into a number of large plates that move and interact
convection currents
transfer of heat by the flowing acation within a liquid or gas- heat rises, cool sinks (moves the plates)
thick layer of rock below Earth's crust; it is a solid, but flows very slowly
Earth's center
outermost solid rock layer
continental drift
continents are drifting across Earth's surface
sea-floor spreading
new ocean crust is creates at mid-ocean ridges as older crust moves away
mid-ocean ridge
underwater mountains that extend into all oceans
subduction zone
when an ocean plate collides with a continental plate, the ocean plate tends to slide inder the continental plate and forms a subduction zone
mountain ranges
occurs when Earth's plates collide and push up
when one plate slides past another
volcanoes and islands
hole in crust, magma rising up from Earth's interior to the surface
folding and faulting
movement of plates can cause tocks to bend, fracture and slide