Earth’s Interior Chapter-1 Section-1 By: Ms. Vigil Science P-1 9/6/04

What is the Science of Geology?  Earth’s hard surface is formed of rock  Geology is the study of the planet Earth  earth’s landforms are the work of natural forces that slowly build up and wear down the land  The earth looks very different than it did thousands of years ago. Earth’s Interior Chp 1-1

What are Surface Changes?  Constructive forces: shape the surface by building up mountains and landmasses. Example: volcanoes, etc.  Destructive forces: shape the surface by slowly wearing away mountains and other features. EROSION  Example: ocean waves, rain, wind, etc.  Continents Earth’s Interior Chp 1-1

Is there indirect evidence of what’s inside the Earth?  Geologists cannot observe Earth’s interior directly via seismic waves  It is over 6,000 kilometers from the surface to the center of the Earth  Seismic Activity –when earthquakes occur they produce seismic waves  Seismic waves travel through the earth—the speed of the seismic waves and the paths they take reveal how the planet is put together Earth’s Interior Chp 1-1

What is Temperature in the Center of the Earth like?  At first as you descend it becomes cool, however,  20 meters + rock is getting warmer  For every 40 m descended, the temperature rises 1 degrees celsius Earth’s Interior Chp 1-1

What is Pressure in the Center of the Earth like?  Pressure is the force pushing on a surface area  The deeper you go, the greater the pressure  Three main layers in the Earth Crust Mantle Core Earth’s Interior Chp 1-1

What is the Crust?  The layer of rock that forms Earth’s outer skin Mountains, rocks, soil & water make-up the surface Ranges from 5 to 40 kilometers  The crust includes both oceanic crust and continental crust Basalt –type of rock that is dark and dense with a fine texture – is found primarily on the ocean floor Granite – type of rock that has large crystals and is light in color and is found primarily on the land Earth’s Interior Chp 1-1

What is the Mantle  A layer of hot rock  Made of two parts major parts at the uppermost part of the Mantle:  Lithosphere and Asthenosphere  Lithosphere Uppermost part of the mantle and lower part of crust which together form a rigid layer approx. 200 km thick Lithos means stone  Asthenosphere Below the lithosphere Soft like tar—it can bend like plastic Earth’s Interior Chp 1-1

What is the core?  The core consists of two parts: Liquid Outer Core and a Solid Inner Core  Outer Core: Layer of molten metal that surrounds the inner core –like a thick liquid  Inner Core Is a dense ball of solid metal Extreme pressure squeezes the atoms of iron and nickel into a tight solid that can’t become a liquid Earth’s Interior Chp 1-1

How does the Earth’s Magnetic Field Work  Currents in the liquid outer core force the solid inner core to spin at a slightly faster rate than the rest of the planet  These currents in the outer core creates Earth’s magnetic field— causes the earth to act like a gigantic bar magnet Earth’s Interior Chp 1-1

Exploring Earth’s Interior pg  Complete project  Scientific drawings of the Earth’s Interior p.22 and a Cross section from Earth’s surface to the center –pg 23. (These drawings are to be taped or glued into the Science journal) Earth’s Interior Chp 1-1

Summarize: HOMEWORK  Geology  Constructive & Destructive Forces  Seismic waves  Temp & Pressure in Earth  Crust  Mantle  Core  Earth’s magnetic field