Structure of Earth

EARTH STRUCTURE AND COMPOSITION

EARTH SIZE AND SHAPE• Earth is almost spherical, or

ball-shaped, however its shape is not perfect.• Earth is a little flattened at its

poles and bulges a bit at its equator

EARTH PROFILE• Mass = 5,882 sextillion metric tons• Volume = 1,083 billion Km3• Total surface Area = 510 million km2• Land Area = 149 million Km2• Water Area = 361 million km2

STRUCTURE OF EARTH• Earth is made of several materials, which

make up different layers.• Earth has four different known layers.

Crust MantleCore

Outer coreInner core

THE CRUST• The Earth’s outermost layer• Earth’s crust is made up of:

SoilRocks

Silicon and oxygen (primary elements)AluminumCalcium….

THE CRUST • Thickness:

5 to 10 km beneath the oceans20 to 70 km beneath the

continents

THE MANTLE• Thickness: About 2900 km• High temperatures (2800 to 3200C)

OUTER CORE• Thickness: About 2250 km• Made up mostly of melted iron and

nickel• Temperatures between 4000 to 5000

C

INNER CORE• Thickness: About 1280 km• Made up of solid iron and nickel• Temperature estimated at 6000

Note: Although the inner core is very hot, it is kept solid due to the great pressure of layers above it

OTHER RESOURCES• http://

www.youtube.com/watch?v=NAHY6965o08

• http://www.youtube.com/watch?v=Q9j1xGaxYzY

• http://www.youtube.com/watch?v=3MFr2cC3erk

LATITUDE AND LONGITUDE• Mapmakers use a set of

imaginary lines that cross each other to identify places on earth.LatitudeLongitude

LATITUDE• Circle Earth in a east-west direction• The central line of latitude, the equator,

divides Earth into the northern and southern hemispheres• It is the distance of a place north or south

of the equator measured in degrees

LONGITUDE• Circle Earth in a north-south direction• It is the distance of a place east or

west of the prime meridian• Prime meridian is the central line of

longitude, which divides Earth into an eastern and western hemisphere

LATITUDE AND LONGITUDE

ROCKS• Rocks are solid Earth materials

formed from a mixture of minerals and sometimes other materials.• They are classified into one of the

three groups based on how they are formed

GROUPS OF ROCKS• The three groups of rocks are:

Igneous rocksSedimentary rocksMetamorphic rocks

IGNEOUS ROCKS• How are Igneous rocks formed?

High temperatures deep in Earth’s crust cause rocks and minerals to melt, forming magma

When magma reaches Earth’s surface it becomes lava• Igneous rocks form when magma or lava cools

and become solid

IGNEOUS ROCKSSome Igneous rocks form from quickly cooled

lavaThey are called extrusive or volcanic (such

as rhyolite)Some igneous rocks form from slowly cooled

lavaThey are called intrusive or plutonic ( such as granite)

SEDIMENTARY ROCKS• What is sediment?• Give some example of sediment

Pieces of rocksMineralsRemains of living things Dissolved minerals that come out of

water

SEDIMENTARY ROCKS• Sedimentary rocks form when sediment

becomes solid material

• How are sedimentary rocks formed?Sediment is moved by wind and water and

piles up on land and riverbed, lake bottoms and the ocean floor. New layers of sediment build up over time pressing down on older layers underneath.

TYPES OF SEDIMENTARY ROCKS• There are three types of sedimentary

rocks.Clastic sedimentary rocksChemical sedimentary rocksOrganic sedimentary rocks

CLASTIC SEDIMENTARY ROCKS• Sandstone• Shale• Many kinds of limestone

CHEMICAL SEDIMENTARY ROCKS

• Rock saltForms when minerals come out

of solution and settle on the ocean floor.

ORGANIC SEDIMENTARY ROCKS

• ChalkForms from the remains of once-

living things

METAMORPHIC ROCKS• Metamorphic rock is rock that has been

changed in form by pressure and heat.Gneiss and slate

• Over time, heat and pressure inside Earth squeeze and melt existing rocks. This process changes the grain size and even the minerals that make up those rocks.