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

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

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.

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

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.

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

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

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.

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

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.

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

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.

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)

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.

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

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