Review Earth’s Structure

Today we will be reviewing the Earth’s structure……You will first watch a review video, then you will rotate around the room to answer your

worksheetYour homework will be completing the assessment on the back!

This will be due next class!

Video

• “A Journey Inside the Earth” (6.27 minutes)• Journey inside the Earth

crust

mantle

Outer core

Inner core

Increased density as we go to the center of earth• The 4 layers have different densities which causes them to separate

• Least dense = crust• Most dense = inner core

• The Earth’s Inner Core:

• Solid iron and nickel layer•Densest layer (causing it to sink to the middle)• The inner core + the Earth’s rotation, creates the

Earth’s magnetic field

•The Earth’s Outer Core: •Liquid layer made of nickel and iron•Spins around the inner core•Earth’s only liquid layer

•The Earth’s Mantle: •below the crust •Made of silicon, magnesium, iron, oxygen•Has CONVECTION CURRENTS

•The Earth’s Crust: •Thin, solid outer layer•Least dense layer •2 types of crust: continental crust• oceanic crusts

• Oceanic Crusts:• under the oceans• More dense (because the ocean compresses it)• Thinner• Made out of basalt

• Continental Crust:• under the continents• Less dense• Thicker• Made out of granite

• The Earth’s crust is divided into 12 major tectonic plates • These plates sit on the dense, hot, layer of the earth known as the

lithosphere• Lithosphere = the crust and uppermost portion of the mantle

• The Earth’s plates move about 2 inches per year (5 centimeters)• Convective currents within the mantle cause the plates to

move• As they move, the plates:• Press against one another (convergent boundary)• Pull apart from one another (divergent boundary)• Scrape against one another (transform boundary)

Plate boundaries……

Convection Currents within the Earth Explained

• 1. The heat source for these currents is heat from Earth’s core and from the mantle itself.• 2. Hot mantle material slowly rises • 3. Causes the tectonic plates to move within the lithosphere (crust

and upper mantle) • 4. As it moves, it cools off and then sinks back into the mantle• 5. Convection currents have been moving inside Earth for more

than 4 billion years (caused Pangaea to separate into 7 continents today we know today).

Volunteers….