1. The Composition AND Structure of the Earth

2. Composition of the Earth
The Earth is made up of 3 main layers:
Core
Mantle
Crust
Mantle
core
The layers are based on compound(s) – a substance composed of two or more elements
Crust

3. The Crust The thin and solid outermost layer above the mantle
5 – 100 km thick
It is the thinnest layer of
the Earth
Less than 1% of
Earth’s mass
Crust

4. The Crust Continental Crust thicker
Oxygen, silicon, aluminum, iron, calcium, and magnesium
Oceanic Crust
thinner, but MORE dense
Almost twice as much iron, calcium, and magnesium

5. The Mantle The layer of rock between the crust and the core
Much thicker and contains most of the Earth’s mass; roughly 2/3 or 67%
The mantle has more magnesium and less aluminum and silicon than the crust
It is more dense than the crust

6. The Core The central part of the Earth below the mantle
Scientist believe the Earth’s core is made mostly of iron and contains smaller amounts of nickel, but almost no oxygen, silicon, aluminum, or magnesium
It makes up roughly 1/3 (33%) of the Earth’s mass.
It is more dense than the crust

7. Layers of the Earth Song!

8. Physical Structure

9. Physical Structure Lithosphere: outermost, solid/rigid layer
made up of the crust and the rigid upper part of the mantle
divided into pieces called tectonic plates
Asthenosphere:
The soft layer of the mantle on which the tectonic plates move
Solid rock that flows very slowly

10. Physical Structure Mesosphere: The strong, lower part of the mantle
Between the asthenosphere and the outer core
Outer Core:
Liquid layer of the Earth’s core
Between the mantle and inner core
Inner Core:
Solid, dense center of the Earth

11. If you look at a map of the world, you may notice that some of the continents could fit together like pieces of a puzzle.

12. Plate Tectonics
Pieces of the lithosphere that move around on top of the asthenosphere
The Earth’s crust is divided into major plates which are moved in various directions.
This plate motion causes them to collide, pull apart, or scrape against each other.
Each type of interaction causes a characteristic set of Earth structures or “tectonic” features.
The word, tectonic, refers to the deformation of the crust as a consequence of plate interaction.

13. World Plates

14. Physical Structure How do scientists know the inside of the Earth?
Seismic waves traveling through the Earth
The waves travel at different speeds due to density in the layers of the Earth
Waves travel faster through solids than liquids
Seismographs measure the waves
This information can track thickness and density of each physical layer