Unveiling Earth's Layers: A Geologist's Insight

1. Chapter One: Plate Tectonics Section One: Earth’s Interior Pages 16-24

2. Title Page • Look over Chapter One: Plate Tectonics (pages 14-47) to help you create a title page in your ISN #43. • Words Worth Knowing will be on ISN #44

3. Geologists… • are scientists who study the forces that make and shape planet Earth. • study the chemical and physical characteristics of rock. • map where different types of rocks are found on and beneath the surface. • describe landforms, features that form in rock by water, wind, and waves.

4. Forces Two groups of forces that change the surface of the Earth: • Constructive forces = shape the surface by building up mountains and landmasses, ex. a new island • Destructive forces = slowly wear away mountains and landmasses, ex. ocean waves wear away a shoreline

5. What is inside the Earth? • Geologists cannot observe Earth’s interior directly so they rely on observations. • When earthquakes occur, they produce seismic waves. Geologists record the seismic waves and study how they travel through Earth. • The data tells us that the Earth is made up of many layers.

6. Seismic Waves • QUEST Explainer: Seismic Waves http://vimeo.com/74338930

7. Journey to the Center of Earth If you could travel to the center of Earth… • What would happen to the temperature as you traveled? • the temperature would rise as you descend • What happens with pressure? • the deeper you go, the greater the pressure; this is because of the weight of the rock

8. Layers of Earth Three main layers make up Earth’s interior: the crust, the mantle, and the core. Each layer has its own conditions and materials.

9. The Crust • The crust is the thin layer of rock that forms Earth’s outer surface; includes both dry land and ocean floor. • Oceanic crust = thin crust beneath the ocean; consists mostly of DENSE rocks like basalt • Continental crust = thick crust that forms the continents; consists mainly of LESS DENSE rocks like granite

10. The Mantle • The mantle is the hot, solid material between Earth’s crust and core. • The mantle is very thick, nearly 3,000 km thick; it goes almost halfway to the center of Earth. • There are 2 fancy layers in the mantle, the lithosphere and asthenosphere.

11. Lithosphere • Lithosphere = a rigid layer consisting of the crust and uppermost part of the mantle • lithos means “stone” • It averages about 100 km thick.

12. Asthenosphere • Asthenosphere = the soft layer of the mantle on which the lithosphere floats • asthenes means “weak” • It is soft, material in this layer flows slowly. • The lithosphere floats on top of the asthenosphere.

13. The Core • Scientists estimate that temperatures within Earth’s outer core and inner core, range from 2,000 to 5,000 *C. • Both made of iron (Fe) and nickel (Ni). • Outer core is liquid while the inner core is solid (so much pressure, Fe and Ni atoms can not spread out)

14. Earth’s Magnetic Field • Currents in the liquid outer core force the solid inner core to spin at a slightly faster rate than the spinning of the whole Earth. • This movement creates Earth’s magnetic field, which causes the planet to act like a giant bar magnet.

15. Compass How does a compass work? • The compass needle aligns with the lines of force in Earth’s magnetic field. • The north seeking end of the compass needle points to Earth’s magnetic north pole. • How a Compass Works https://www.youtube.com/watch?v=lSaXhVEE4oQ

16. Words Worth Knowing (ISN #44) • Geologist • Constructive forces • Destructive forces • Seismic wave • Basalt • Granite • Lithosphere • Asthenosphere