ch 7 study guide 1 and 2

state the layers of the earth

The Earth is Divided into three Layers the Crust, Mantle and the core. The crust is the outer layer thay we live on. There are 2 types of crust The Continental which is similar to granite and the Oceanic which is similar to Basalt. The next layer is the mantle wich is the thickest and contains most of the mass. The middle part of the earth is called the core. The Earth is divided into five main physical layers - the lithosphere, asthenoshere, mesosphere, outer core, and inner core. The lithosphere is the outermost rigid layer of the earths that consist of the crust and the rigid upper part of the mantle. The asthenosphere is a soft layer of the mantle in which pieces of the lithosphere move. The mesosphere is latterly , the middle sphere - the strong, lower part of the mantle between the asthenosphere and the outer core. The outer core is the liquid layer of the earths core that lies beneath the mantle and surrounds the inner core. The inner core is the solid dense center of our planet.the lithosphere move. The mesosphere is latterly , the middle sphere - the strong, lower part of the mantle between the asthenosphere and the outer core. The outer core is the liquid layer of the earths core that lies beneath the mantle and surrounds the inner core. The inner core is the solid dense center of our planet.

describe the evidence that supports the theory of continental drift.

The theory explained how some of the continents fit well together and how fossils of the same plant and animal species are found on both sides of the Atlantic ocean. Also how similar rock typles and ancient climatic conditions were found on several continents.

describe sea-floor spreading

There is a chain of mountains under the water running through the center of the Mid-Atlantic ocean called the Mid-Ocean ridge. This is where sea-floor spreading takes place and magma has risen to fill the gap. It is noted that the crest is older the farther away it is from this ridge. You can tell how long this has taken because the oldest crust closest to the continents date back to the dinosaurs'. The magnetic pools have reversed several times which we can tell by the way the magnetic mineral grains point. This also proves the sea floor is spreading.

asthenosphere

a soft layer of the mantle in which pieces of the lithosphere move and is part of the upper mantle.

mesosphere

beneath the asthenosphere is the strong lower part of the mantle.

core

the central, spherical part of the Earth below the mantle.

mantle

the layer of the earth between the crust and the core.

outer core

the liquid layer of the earths core that lies beneath the mantle and surrounds the inner core

lithosphere

the outermost rigid layer of the earths that consist of the crust and the rigid upper part of the mantle

tectonic plates

the pieces of the lithosphere that move around on top of the asthenosphere.

Sea-floor spreading

the process by which new oceanic lithosphere is created as older materials are pulled away.

inner core

the solid dense center of our planet that extends from bottom of the outer core to the center of the earth.

continental drift

the theory that continents can drift apart from one another and have done so in the past.

state Alfred Wegener's theory of continental drift

the theory that continents can drift apart from one another and have done so in the past.

crust

the thinutmost layer of the earth or the uppermost part of the lithosphere