1. (try…give it a shot! Not trying = zero)
BELL RINGER
What do you think is the difference between describing something based on its chemical composition vs. its physical properties?
(try…give it a shot! Not trying = zero)

2. Plate Tectonics
Pt 1 – INSIDE THE EARTH

3. Composition of the earth
The Earth is made of several layers.
Scientists think about these layers in two ways – by their composition and their physical properties.

4. Earth’s layers
The 3 layers of Earth are defined based on the compounds that make up each layer.
The Crust
The Mantle
The core
Compound: a substance composed of two or more elements.
The less dense compounds make up the crust and mantle.
The more dense compounds make up the core.

5. The crust The thin and solid outermost layer of the Earth.
Makes up 1% of the Earth’s mass
5-100 km thick
There are two types of crust:
Continental – thicker and less dense
and
Oceanic Crust – thinner and more dense

6. The Mantle The layer of Earth between the crust and the core.
Makes up 67% of the Earth’s mass
2,900 km thick
Scientists must draw conclusions about the mantle based on observations of mantle rock and magma which push through the crust.

7. The Core The central part of the Earth below the mantle.
Makes up 33% of Earth’s Mass
3,430 km thick

8. Notes break Name the 3 layers of the Earth
Which layer is directly under our feet?
Out of continental and oceanic crust, which is more dense?

9. 5 Physical layers Based on their physical properties:
Lithosphere: The outermost rigid layer of Earth’s crust, and the upper layer of the mantle.
Divided into pieces called tectonic plates.
Asthenosphere: A “plastic” layer of the mantle on which pieces of the lithosphere move.
Made of solid rock which flows very slowly.
Mesosphere: strong, lower part of the mantle under the asthenosphere and above the outer core.

10. 5 Physical layers
Outer core – Liquid layer of Earth’s core that lies beneath the mantle and surrounds the inner core.
Inner core – Solid, dense center of our planet that extends from the bottom of the outer core to the center of the Earth.

11. Tectonic plates fit
Definition: A block of lithosphere that consists of the crust and the rigid, outermost part of the mantle.
Tectonic plates fit like a jigsaw puzzle.

12. Tectonic plates Float
The plates are not stationary, they are “floating” on the asthenosphere like ice cubes in a bowl of punch!
Continental crust tends to displace more of the asthenosphere than oceanic crust…
Why? ________________________________________________

13. Activity
Journey to the center of the Earth short story – In your groups, with the help of your books, write a short story of your imaginary journey to the center of the Earth.
Describe the chemical and physical layers you are traveling through, what they feel like, how they look, what tools you need to get through them.