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Science

* Earths outermost layer is the crust, the rigid rock of continents and ocean floors.

* Under the crust lies the mantle, which is nearly 3000km thick.

* 3 layers within the mantle. Beneath the crust is the solid outer mantle. Together with the crust this layer forms the rigid lithosphere. Beneath the lithosphere is the asthenosphere. It is hot and has so much pressure on it from the lithosphere above that it behaves like a viscous fluid, or soft plastic even though it is solid mantle. Beneath that is a dense inner layer of lower mantle.

* The core is the nearly spherical center of the earth. The outer core consists of liquid iron and nickel. While the inner core is mostly very dense solid iron.

FINDING OUT ABOUT EARTHS STRICUTURE

SCIENTISTS obtain information through direct and indirect observation

Direct observation

* Volcanoes provide scientists with one of the best ways to directly observe earth’s interior.

Indirect observation

* Scientist use observations made at the surface of the earth to make suggestions. About the structures and processes underground.

Modern mapping

* Helps scientist to plot the locations of geological formations.

Evidence of a dynamic earth

* The puzzle fits of the continents

* Match of geological features on distant coastlines

* Identical ancient fossils on distant coastlines

* Presence of coal deposits in non-tropical areas

* Evidence of glaciers near the equator

The fossil record

* Rare plants and animals found in distant parts of the world

Matching mountains

* Large coal deposits formed from lush tropical forests 350 million years ago have been found far from the tropics in Antarctica.

* Folded mountains such as the Appalachians in the northeast United States have distinct patterns of rock layers.

Ancient Glacial Evidence

* Glaciers scour (clean wipe or rub) the rock in their path providing evidence of Paleoglaciation (when more than one of the...