1. If you were lost, how could a dog help?
A new study says that dogs choose the direction they relieve themselves based on our planet's magnetic field.

2. Inside the Earth How do scientists know?

3. Earth in General
3 Layers
Crust
Mantle
Core
Diameter
12,750 km

4. Cross Section Diagram

5. Overview of the Crust Solid Basalt and Granite 5-100 km thick
Coolest in temperature
Least dense
g/cm3
Like the “shell of egg,” is brittle and can break
Layer we live on

6. What is the difference between sediment and bedrock?
Sediment is
Smaller pieces of broken rock mixed with organic material and remains
Bedrock is rock
underneath the accumulated
sediment

7. Overview of Crust (continued)
Major changes
Plate Tectonics
Minor changes
Weathering & erosion
Deposition of sediments
Two types of Crust
Oceanic (very dense, made of basalt)
Continental (less dense, made of granite)

8. Example of minor change & a bit of New Hampshire folklore
For A. Cleary

9. Oceanic and Continental Crust
Oceanic Crust
Mainly Basalt
Thinnest part of crust ~ 5 km thick
Density 3.0 g/cm3
Ocean puddles on top
Youngest part of crust, new crust is made here
Continental Crust
Mainly Granite
Thickness varies but ~ 30 km thick
100 km thick under Himalayans Mts.
Density 2.7 g/cm3
Oldest part of crust

10. Overview of the Mantle Like “white” of egg
Hot layer of semi solid rock
Contains more iron, magnesium and calcium than crust
Hotter & denser… temp and pressure increase w/depth
~2900 km thick
Density 3.4 – 5.6 g/cm3
Multiple layers which have
different densities

11. Upper Mantle and Lower Mantle
~720 km thick
Density 3.4 – 4.4 g/cm3
~1480 C, rock is near melting
Magma from some volcanoes can originate here
Lower Mantle
~2170 km thick
Density 4.4 – 5.6 g/cm3
~ 2600 C
Higher level of magnesium & silicon oxides

12. Overview of the Core Mostly iron & nickel, metal
Core is not rock or fire
~3300 km thick
Twice as dense as mantle

13. Outer Core Liquid nickel and iron 2200 km thick
Density 9.9 – 12.2 g/cm3
~3800 C

14. The inner core is solid but hotter than the outer core; why?
Solid nickel and iron
1250 km thick
Density 12.2 – 13.1 g/cm3
~4300 C
The inner core is solid but hotter than the outer core; why?

15. Where does the core get its heat?
Chunks of material collided and stayed together, (Heat from these collisions can be on the order of 10,000 kelvins about 18,000 degrees Fahrenheit).
Friction, when denser core material sinks
Decay of radioactive elements, mostly uranium and thorium according to physicists.

16. How are the earth’s layers similar to an egg?
Shell=crust
Egg white=mantle
Yolk=core

17. Interactions between Layers
Lithosphere
Includes crust and solid, uppermost part of the mantle
Broken into about 19 pieces, these pieces are called “PLATES”
The plates move on top of the Asthenosphere (which is a thin layer of the upper mantle)

18. Interactions between Layers
Asthenosphere
Beneath the lithosphere, in the mantle, lies a soft, relatively weak region of rock that flows slowly (like soft plastic or hot asphalt)
Convection Currents that drive the movement of plates happen in the Asthenosphere

19. Vocabulary expected to know
Sphere – shaped like a ball Hemisphere – half of a sphere Interior – inside Exterior – outside Cross Section – diagram that shows a piece “cut out,” so you can see the inside Molten – melted, usually referring to material that melts at very HIGH temperature

20. Vocabulary expected to know
*Lava – melted rock touching atmosphere *Magma – melted rock below the crust Tectonic Plates – broken pieces of the lithosphere

21. Tectonic Plates Earth’s crust is broken into about 19 pieces
These plates move on top of the asthenosphere (thin layer of the upper mantle)