If you were lost, how could a dog help?

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 EarthHow do scientists know?

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

4. Cross Section Diagram

5. Solid Basalt and Granite 5-100 km thick Coolest in temperature Least dense 2.2-2.9 g/cm3 Like the “shell of egg,” is brittle and can break Layer we live on Overview of the Crust

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. 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 Overview of the Mantle

11. Upper Mantle and Lower Mantle Upper 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. Inner Core • 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 Earth’s Layers

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)