1. Changes Within the Earth Coach Parrish 7 th Grade History Oxford Middle School

2. Physical Characteristics Geology – the study of the earth’s physical structure and history. Geology – the study of the earth’s physical structure and history. The Earth’s Layers 1. Core – center of the earth that consists of very hot metal, mainly molten lava. 2. Mantle – a thick layer of rock that surrounds the core. Scientists measure the mantle at 1800 miles thick. 3. Crust – the outer layer of the earth. Scientists measure the crust to be about 5 miles thick.

3. The Earth’s Layers

4. Land, Air, and Water The area on and around the earth is made up of “spheres.” The area on and around the earth is made up of “spheres.” 1. Lithosphere – Soil, rocks, landforms and other surface features. 2. Atmosphere – the layer of air and water about the earth. 3. Hydrosphere – consists of water in oceans, lakes, and rivers on the earth. 4. Biosphere – world of plants and animals on the earth.

5. Physical Processes Physical processes help to shape the landforms on earth in the form of volcanoes and earthquakes. Physical processes help to shape the landforms on earth in the form of volcanoes and earthquakes. Volcanoes – form when magma from the earth’s core break through the earth’s crust. Volcanoes – form when magma from the earth’s core break through the earth’s crust.

6. Explaining Volcanoes and Earthquakes Most scientists agree that Volcanoes occur because of plate tectonics. Most scientists agree that Volcanoes occur because of plate tectonics. Plate tectonics – theory that the earth’s crust is made up of many movable plates that cause volcanoes and earthquakes. Plate tectonics – theory that the earth’s crust is made up of many movable plates that cause volcanoes and earthquakes.

7. Volcanoes Over time, as volcanoes continually erupt, the lava cools and hardens adding layers to the Earth. These examples are from Mt. Fuji – Japan. Over time, as volcanoes continually erupt, the lava cools and hardens adding layers to the Earth. These examples are from Mt. Fuji – Japan.

8. Ring of Fire Ring of Fire – series of mountains created by volcanoes surrounding the Pacific Ocean. Ring of Fire – series of mountains created by volcanoes surrounding the Pacific Ocean.

9. Earthquakes The movements of earth’s crust can sometimes cause earthquakes. When rocks on either side of a fault move suddenly, an earthquake occurs. The movements of earth’s crust can sometimes cause earthquakes. When rocks on either side of a fault move suddenly, an earthquake occurs. The next slide shows where the fault lines are located on the earth and what they look like!

10. Fault Line Picture

11. Continental Drift Theory During the 1600s, people started noticing that the continents could have fit together at one time. During the 1600s, people started noticing that the continents could have fit together at one time. In the early 1900s, a German explorer and scientist named Alfred Wegener suggested the continental drift theory. In the early 1900s, a German explorer and scientist named Alfred Wegener suggested the continental drift theory. Continental Drift Theory – idea that at one time, earth only had one continent called Pangaea. Over time, the continents separated into what we know today. Continental Drift Theory – idea that at one time, earth only had one continent called Pangaea. Over time, the continents separated into what we know today.

12. Continental Drift Theory Here is a picture of the continental drift theory. Here is a picture of the continental drift theory.