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.

Inside the Earth How do scientists know?

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

Cross Section Diagram

Overview of the Crust 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

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

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)

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

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

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

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

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

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

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?

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.

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

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)

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

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

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

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)