Composition of the Earth.ppt

Composition of the Earth

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
core
Mantle
Crust
•The layers are based on
compound(s)–a
substance composed of
two or more elements

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 10-12 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