Earth’s StructureChapter 4

Earth’s Interior

0Made up of 3 major compositional zones and 5 structural zones.

Layers of the Earth

Compositional Zones

0Crust: outermost layer0Makes up 1% of Earth’s mass0Oceanic (5-10km) & continental

(15-80km)0Moho: lowest layer of crust

Compositional Zone

0Mantle: denser than crust02,900 km thick (2/3 of Earth’s

mass)0Core: center of the Earth0Made of iron and nickel

Structural Zones

03 compositional zones are divided into 5 structural zones.

0Lithosphere: Part of the mantle & crust above it.0Cool & brittle

0Asthenosphere: Solid rock is able to flow. 0Very hot and has high pressure

0Mesosphere: Layer of solid mantle rock0Outer core (liquid)0Inner core (solid)

Earth as a Magnet

0Has 2 magnetic poles0Motions in the core

produce electric currents that create magnetic field.0Shaped by solar

winds

Earth’s Rotation

0The spinning of Earth around its axis is called rotation.

01 full rotation = 24 hours0 Evidence

0Foucault Pendulum – Large pendulum that shifts 11 every ̊�hour in a clockwise direction.

0Coriolis Effect – Winds are deflected to the right in N. Hemisphere and to the left in the S. Hemisphere.

Effects of Rotation

0Sun appears to rise in the east and set in the west.0Standard Time Zones

0 Based upon the rate in which the sun appears to move across the sky.

0 Starting point for the standard time zone is the prime meridian.

0 Passes through Greenwich, England (longitude 0 ) ̊�0 International Date Line

0 Longitude where the date changes.0 180th meridian

Standard Time Zones

Every 15 degrees of longitude equals one hour of time

International Date Line

Moving from left to right…subtract one day

Moving from right to left…add one day

Earth’s Revolution

0The Earth’s orbit around the sun.0It takes about 365 days to complete one

full revolution.

Ellipse

0The shape the earth’s orbit takes around the Sun is called an ellipse; an elongated closed curve

0The sun is not in the center of the ellipse0Thus, the distance between the sun and earth

changes.

Ellipse

The Northern Hemisphere’s summer The Northern Hemisphere’s winter

Equinox

0When the sun is directly above the Earth’s equator.0Daylight = night time in both hemispheres.0Spring equinox and Autumnal equinox

Solstice

0The sun’s direct rays reach their greatest distance north or south of the equator.023.5 N and 23.5 S. ̊� ̊�0Winter and Summer solstice

Credits

0 Spaulding, Namowitz (2003). Earth Science. Evanston, IL: McDougal Littell Inc.

0 Photos0 http://www.theozonehole.com/coriolis.htm0 http://

oceanexplorer.noaa.gov/explorations/05galapagos/logs/dec22/media/magfield_600.html

0 http://oceansjsu.com/105d/exped_commotion/5.html0 http://en.wikipedia.org/wiki/File:Pendule_de_Foucault.jpg0 http://

en.wikipedia.org/wiki/File:Earth-lighting-equinox_EN.png