1. The Earth As A System

2. What is a System A system is single unit made up of interconnected structural parts that carry out needed functions for the unit. For example the Integumentary system of the human body is made up of the skin, hair, nails and glands. Each organ carries out a specific function for the body. Skin keeps out bacteria and protects the organs Hair protects against the external environment Nails protects the nerve endings of the fingers and can defend Glands keep the body moist, water resistant and cool.

3. The Earth as a System The Earth system is made up of A. The Geosphere-The rocks, soil and sediment found on Earth’s Surface B. The Atmosphere-The air layer that we breathe surrounding the Earth made up of a mixture of gases C. The Hydrosphere-All of the water on or near the Earth’s surface. ¾ of the Earth’s surface is covered by oceans. The remaining ¼ is found in the atmosphere, in ponds, rivers, streams, lakes, glaciers and in the soil. D. Biosphere-made up of the regions where life exists. This area extends approximately 5 miles above the Earth down to the bottom of the ocean. The Earth is 12,756 km from edge to edge through the center at the equator How many miles is this ? (Hint multiply kilometers by.62 to find miles)

4. Composition of the Earth The Earth is divided into 3 main layers A. The Core – the densest, composed of solid Iron metal (Fe). Because Iron is so heavy and dense, during the formation of the Earth it sank and became the rocky center of the planet. The Core has an outer molten layer and an inner solid layer and is 3400 km thick B. The Mantle-the layer sandwiched above the Core makes up 64 percent of the Earth, is approximately 2900 km thick C. The Crust –the lightest of Earth’ 3 layers extends 5 -8 km beneath the oceans and is 20 to 70 km beneath the continents.

5. The Physical Structure of the Earth The Earth is divided up into 5 layers based on the physical properties of each layer 1. The outermost 15-300 ridgid layer that includes the crust and uppermost mantle. It is divided into huge tectonic plates. 2. The Asthenosphere- 250 km is the layer beneath the lithosphere and is made up of rock that flows very slowly and allows the tectonic plates to move on top of it. 3. The Mesosphere-2550 km the lower part of the mantle 4. Earth’s Outer Core-2200 km a dense liquid layer made up of molten Iron, Magnesium and Silica. It is this layer that gives Earth it’s magnetic trait. 5. Earth’s Inner Core-1228 km a solid, dense center made up mostly of iron and nickel. The temperature of the inner core is 4000 to 5000 degrees C.

6. Discovering Earth’s Interior Scientists have never drilled completely through the Earth so how do they know what the earth is like on the inside Wellllllll! Scientists created technology based on real Earthquake seismic waves to characterize Earth’s interior. They use a giant thumper To create energy that they can measure. Remember the movie Tremors A Seismic waves vibration is altered by the kind of material it passes through. Scientists measure the change in speed and direction of these waves and this information allows them to make inferences about what kind of material is there. It’s way to hot for any human or any living thing to live close to the center of the Earth!

7. Earths Cycles Matter in Earth’s System is recycled over and over again There are 2 main sub cycles of the Earth System 1. The Hydrologic or Water Cycle 2. The Rock Cycle A change in one part of the cycle causes a change in another part

8. Heat for the Planet Earth receives heat from 2 sources 1. 1. The sun-even though the sun is 93 m miles away it provides enough radiant energy to support life on the planet 2. 2. Earth’s interior- without heat from within,the planet would not be able to support life on the surface Together the sun and the heat given off by Earth’s interior keep the planet warm enough for life to thrive and continue

9. What do You Know-I Think You Know a Lot Name and describe the 4 systems of the Earth. How many layers does the Earth have? Which of Earth’s 3 layers is the heaviest? Why? Which of Earth’s 3 layers is the thinnest? Name the two regions of the core. There are ___layers based on the physical properties of the Earth. Why is the inner core solid, even though it is 4000 degrees down there. What is the correct order of Earth’s physical layers going from outer most to inner most layer? Why are scientists sure about the physical characteristics of Earth’s interior? How do they know? Raw materials of the planet are recycled through the ______ and _______cycles What are the 2 sources of heat that warm the planet and sustain life?