1. Plate Tectonics
Mrs. Ramsey 6th Science

2. Inside the Earth Composition of earth: Divided into three layers
Crust: km think. Thinnest layer
Mantle- thicker than crust, contains most of earth’s mass.
Core- makes up 1/3 of earths mass

3. Inside the earth Physical structure of the earth
Lithosphere- outermost layer; made of crust and mantle
Asthenosphere- plastic layer where lithosphere moves
Mesosphere- strong lower part of mantle
Outer core- liquid layer of earth’s core that surrounds inner core
Inner core- solid and dense center of planet

4. Inside the earth Tectonic plates
Think of lithosphere as “Giant jigsaw puzzle”
Major tectonic plates
1. Pacific plate
2. North American plate
3. Cocos plate
4. Nazca plate
5. South American plate
6. African plate
7. Eurasion plate
8. Indian plate
9. Australian plate
10. Antarctic plate

5. Inside the Earth
Some tectonic plates have both oceanic and continental crust. Look at pg 195 for reference.
Answers about our earth’s core sometimes come from earthquakes.
When a earthquake happens seismic waves are produced resulting in vibrations. Their speed depends on density and composition of what they are traveling through.
Seismograph can measure seismic waves