1. Notes= Yellow

2.  There are two ways that scientists label the layers of the Earth. Composition layers Physical layers

3.  These are the more familiar layers. They are: Crust  Ranges from 5 to 100 km in thickness  Thinnest layer of the Earth  Split into two types: Continental and Oceanic Mantle  Roughly 2900 km thick  No one has ever drilled to the mantle. It is also very hot Core  Mostly made of iron and nickel  The core’s diameter is roughly 6856 km (about the size of Mars)

4.  The less familiar layers are the physical layers. They are based on how the layer looks or acts. Lithosphere “rock sphere” (15-300 km)  The tectonic Plates  A combination of crust and the upper region of the mantle  Cold and brittle (easily broken) Asthenosphere “weak sphere” (250 km)  Hard rock that acts like warm tar or honey

5. Mesosphere “middle sphere” (2550 km)  Rest of the mantle  Much stronger and hotter than the Asthenosphere Outer Core (2200 km)  Liquid layer Inner Core (diameter= 2456 km)  Solid, dense core of the planet

6.  Did you know?... The center of the Earth’s core is hotter than the surface of the sun. The temperature of Earth’s inner core reaches 6000 °C whereas the surface of the sun is roughly 5500 °C.  The sun’s core, however, is 15,000,000 °C

7. LithosphereAsthenosphere Mesosphere Outer Core Inner Core CrustMantle Core

8.  Theory by Alfred Wegener  Continental drift is the theory that continents can drift apart from one another and have done so in the past. Puzzling observations that could be explained by continental drift:  Puzzle-like fit of the continents  Fossils of the same plants and animals found on both sides of the Atlantic Ocean  Strange grooves cut by ancient glaciers that line up

9.  With the idea that continents can drift apart, scientists felt that some force had to be making these continents move.  The theory of plate tectonics developed as a way to explain continental drift

10.  Tectonic plates are large pieces of the lithosphere that move around on top of the asthenosphere like icebergs in the ocean.  There are 10 major plates

11. The Core solid innersolid inner liquid outerliquid outer density of 10-13 gm/cm³density of 10-13 gm/cm³ The Mantle surrounds the coresurrounds the core density of 3.3-5.7gm/cm³density of 3.3-5.7gm/cm³ three distinct zonesthree distinct zones The Crust oceanic - 3 gm/cm³oceanic - 3 gm/cm³ continental - 2.7 gm/cm³continental - 2.7 gm/cm³ Plate Tectonic Theory explains the interactions of these zones

12.  Plate tectonics is the theory that the Earth’s lithosphere is divided into large tectonic plates that move around on top of the asthenosphere. All plates share boundaries with other plates, just like states share borders.

13.  There are three main types of boundaries Convergent  When plates push against each other Divergent  When plates move away from each other Transform  When plates slide against each other  Online animations Online animations

16. crust Inner core Outer core mantle

17. Joshua and Jennifer Mosser, Briar Woods High School Inner core is solid and made of iron and nickel Outer core is liquid and made of Fe, N, and lighter elements Mantle is largest layer and is plastic-like (asthenosphere) Two (2) types of crust— continental (made of silicon and oxygen) and oceanic (made of iron and magnesium)

19.  This movement of heat energy causes the tectonic plates to move.

20.  When oceanic plates collide with another oceanic plate or a continental plate, one may be pushed under the other causing magma to rise thus forming volcanoes.

22.  This movement of heat energy causes the tectonic plates to move.

25. How the Earth’s Core affects the travel of seismic waves. (After C.F. Richter (1985) Elementary Seismology, W.H. Freeman) Mantle INNER CORE S-wave shadow zone P-wave shadow zone

26. Volcanoes form at the ridge(s) and at the subduction zones

27. Lesser Antilles Subduction Zone I M S M M