Chapter 1

Earth Science

name for all sciences that collectively seek to understand Earth and its neighbors in space


study of earth" -physical geology = examines materials composing Earth and seeks to understand the many processes that operate beneath and upon its surface-historical geology = understand origin of Earth and development of planet through its 4.5 billion year history


study of oceans in all their aspects and relationships


study of the atmosphere and processes that produce weather and climate


study of the universe


everything that surrounds and influences an organism

physical environment

encompasses water, air, soil, and rock, as well as conditions such as temperature, humidity, and sunlight


can be replenished over relatively short time spans


continue to form but processes that creat them are so slow that significant deposits take millions of years to accumulate ex: aluminum, copper, iron, oil, natural gas, coal


tentative/untested explanation


well-tested and widely accepted view that the scientific community agrees best explains certain observable facts


explain a large number of interrelated aspects of the natural world

geological time scale

divides 4.5 billion year history of earth into many different units and provides a meaningful time frame within which the events of the geological past are arranged

nebular hypothesis

bodies of our solar system evolved from an enormous rotating cloud called the solar nebula


dynamic mass of liquid that is continually on the move, evaporating from the oceans to the atmosphere, precipitating to the land, and running back to the ocean again


life-giving gaseous envelope


includes all life on earth


earth's relatively thin, rocky outer skin, is of two different types - continental crust and oceanic crust


a solid, rocky shell that extends to a depth of nearly 2900 km; bountary between the crust and mantle represents a marked change in chemical compoisition


weak sphere"; stiff layer to a depth of about 350km; top portion of the asthensophere has a temperature/pressure regime that results in a small amount of melting

lower mantle

depth of 2900km, strengthens in depth, very hot and capable of very gradual flow


iron-nickel alloy with minor amounts of oxygen, silicon, and sulfur - elements that readily form compounds with iron

outer core

liquid layer 2260km thick; the movement of metallic iron within this zone generates Earth's magnetic field

inner core

sphere having a radius of 1216km; the iron in the inner core is solid due to the immense pressure that exist in the center of the planet

plate tectonics

first comprehensive model of earth's internal workings

lithospheric plates

earth's rigid outer shell (litosphere) broken into numerous slabs which are in continual motion