Chapter 1

1. Chapter 1 Plate Tectonics

2. Chapter 1 Earth’s Interior Key Terms: • Geologist- Scientist that study the forces that make and shape Earth. • Geology- The study of planet Earth. • Seismic Wave- A vibration traveling through Earth carrying the energy released during an earthquake. • Pressure- The amount of force pushing on an area.

3. Chapter 1 Key Terms: • Crust- Layer of rock that forms Earth’s outer surface. • Basalt- A dark, dense igneous rock found in the oceanic crust. • Granite- Usually a light colored rock found on Earth’s continental crust. • Mantle- The layer of hot solid material between the crust and the core.

4. Chapter 1 Key Terms: • Lithosphere- A rigid layer made up of upper part of the mantle and the crust. • Asthenosphere- Soft layer of the mantle on which the lithosphere floats. • Outer Core- Layer of molten iron and nickel that surrounds the inner core. • Inner Core- Solid iron and nickel in the center of the earth.

5. Objective: The students will determine methods used by geologists to explore the interior of the earth.

6. Finding directEvidence • Geologists study the processes that create Earth’s features and search for clues about Earth’s history. • Scientists cannot travel inside the Earth to explore it. So scientists must learn about Earth’s interior, or inside, in other ways. • Scientists use drills to get rock samples from inside Earth. The rock samples help scientists learn what conditions were like inside the earth when rocks formed.

7. Finding Indirect Evidence • Geologists study how seismic waves travel through Earth. Seismic waves are waves made by earthquakes. • Seismic waves show that Earth is made up much like an onion. • How? • It has layers. (Like an ogre)

8. A Journey to the Center of the Earth • Earth has three main layers. The CRUST is the outside layer, the MANTLE is the middle layer. The CORE is the inside layer. Temperature • Temperature increases from crust to the core. It is very hot inside Earth. One reason it is so hot is that some substances inside Earth give off energy. Pressure • Pressure also increases from the crust to the core. Pressure is caused by a force pressing on an area. There is great pressure inside Earth because of all the rock pressing down from above.

9. Objective: The students will diagram and describe the layers of the earth.

10. Parts of the Earth

11. The Crust • The crust is a layer of rock that forms Earth’s outer skin. The crust is Earth’s thinnest layer. It is only 5 to 70 kilometers thick. • The crust that makes up the ocean floors is called the oceanic crust. Oceanic crust is made mostly of a rock called basalt. • The crust that makes up the continents is called continental crust. Continental crust is made mostly of a rock called granite. • Continental crust is thicker than oceanic crust.

12. The Mantle • The mantle is the layer below the crust. The mantle is Earth’s thickest layer. The mantle has three parts. • The top layer of the mantle, along with the crust, is the lithosphere. The top layer of the mantle is hard rock. • The middle layer of the mantle is the asthenosphere. The middle layer is soft rock, like hot road tar. • The bottom layer of the mantle is called the lower mantle. It is also hard rock.

13. The Core • The core is Earth’s inside layer. The core has two layers: the outer core and the inner core. • The outercore is made of liquid metal. The liquid metal flows in currents. The currents make Earth act like a giant magnet, with north and south poles that attract iron. • The inner core is made of solid metal. The inner core is solid because it is under so much pressure.

14. Parts of the Earth • Crust-Mantle • Crust-Mantle-Core

15. Ticket Out Identify the interior parts of the Earth. Brain Pop- Earth's Structure Interior Ticket Out

16. Section 2Convection Currents and the MantleKey Terms: • Heat Transfer- The movement of energy from a warmer object to a cooler one. • Radiation- The transfer of energy through empty space. • Conduction- Heat transferred by direct contact of particles of matter.

17. Section 2 Key Terms • Convection- Heat transfer by the movement of heated fluid. • Density- How much mass there is in a volume of a substance. • Convection Current- The flow that transfers heat from one part of a fluid to another.

18. Objective: The students will explain how heat is transferred.

19. Types of Heat Transfer • When an object heats up, particles in the object have more energy and move faster. This energy can travel, or transfer, from a warmer object to a cooler object. This is called heat transfer. • There are three types of heat transfer: radiation, conduction, and convection.

20. Radiation • Radiation is the transfer of energy through space. For example, sunlight travels through space by radiation and warms Earth’s surface. Radiation also explains why your hands get warm when you hold them near a fire.

21. Conduction • Conduction is the transfer of heat between objects that are touching. If you touch a hot pot, heat travels from the pot to your hand by conduction.

22. Convection • Convection is the transfer of heat by the movement of particles in fluids such as water. Moving particles transfer heat throughout the fluid.

23. Types of Heat Transfer • REMEMBER: • Radiation transfers heat through the air. • Conduction transfers heat through solids. • Convection transfers heat through liquids. Convection, Radiation, Conduction

24. Objective: The students will identify the cause of convection currents.

25. How Can Heat Cause Motion in a Liquid? • As you watch the demonstration, think about the following: • How do you explain what happened to the droplets of food coloring? • Why do you think the second droplet moved in a way that is different from the way the first droplet moved?

26. Convection in the Earth’s Mantle • Remember, convection is the transfer of heat by the movement of particles in fluids. This movement of particles is called a convection current. • A convection current starts when there are differences in temperature and density in a fluid. Density is the amount of mass in a given volume of a substance. A high-density substance feels heavy for its size. What does this mean???

27. What does this mean? • Suppose you put a pot of soup on a stove. The soup at the bottom of the post gets warm first. Because it is warmer, the soup at the bottom is less dense than the cooler soup above it. So the warmer soup rises. At the same time, the cooler, denser soup sinks to the bottom of the pot. • The cooler soup now at the bottom gets warmer, and the process repeats. A constant flow of particles begins. Warmer soup keeps rising, and cooler soup deeps sinking. This movement of particles transfers heat throughout the soup.

28. Convection Currents in Earth • The heat inside Earth causes convection currents in the mantle and outer core. • Convection currents inside Earth are like convection currents in the pot of soup. Hot materials at the bottom rise to the top. Cooler materials at the top sink to the bottom. • Convection currents in the mantle move very slowly. This is because the mantle is made of solid rock.

29. Convection Currents in Earth • Remember, Earth is like a giant magnet because of currents in the outer core. Those currents are convection currents. lithosphere asthenosphere mantle

30. Section 3Drifting ContinentsKey Terms: • Pangaea- The name of the landmass in the theory that all the continents were joined at one time. • Continental Drift- The idea that the continents slowly moved over the earth’s surface. • Fossil- Any trace of an ancient organism that has been preserved in rock.

31. Objective: The students will explain the theory of continental drift.

32. The Theory of Continental Drift • Some continents are shaped like puzzle pieces. For example, the west side of Africa and the east side of South America look like matching puzzle pieces.

33. The Theory of Continental Drift • Scientist Alfred Wegener (VAY guhner) tried to explain why continents are shaped this way. • Wegener thought that Earth had one big continent about 300 million years ago. The big continent broke into smaller pieces and formed smaller continents. The continents slowly drifted apart. Wegener called this CONTINENTAL DRIFT. • Wegener named this supercontinent PANGAEA, meaning “all lands.”

34. Pangaea

35. Objective: The students will explain evidence of the theory of continental drift.

36. Wegener’s Evidence • Evidence shows that continental drift really happened. • Wegener studied information from three sources to prove that his theory was correct. He studied... 1- Landforms 2- Fossils 3- Climate changes

37. Evidence from Landforms • Mountains in Africa and South America line up like they were once part of the same mountain range.

38. Evidence from Fossils • Fossils from plants and animals have been found to support Wegener’s theory. The plant Glossopteris was found in rock in Africa, India, Australia, and Antarctica. • The seeds would be to large to have been carried to the continents as they are today.

39. Evidence from Climate • Other evidence shows that continents’ climates have changed. This could happen if continents had drifted. • Tropical plant fossils found on an ice covered island north of Norway. • Deep scratches in rock show possible continental glaciers in Africa. • Wegener's theory was Earth’s climate has not changed, but the position of the continents has.

40. Scientists Reject Wegener’s Theory • Wegener could not explain what causes continental drift. So most other scientists of his time thought he was WRONG! New evidence???? • Wegener used his idea of continental drift to explain how mountains form. Wegener thought mountains form because drifting continents bump into each to other. When this happens, edges of the continents crumple. The crumpled edges form mountains.

41. Section 4Sea Floor SpreadingKey Terms: • Mid-Ocean Ridge- The longest chain of mountains in the world. • Sonar- A device that bounces sound waves off underwater objects then records the echoes of the sound waves. • Sea-Floor Spreading- The process of molten material being added to the oceanic crust.

42. Section 4 Key Terms: • Deep-Ocean Trench- A deep valley along the ocean floor through which oceanic crust slowly sinks towards the mantle. • Subduction- The process by which the oceanic crust sinks beneath a deep ocean trench and back into the mantle at a convergent plate boundary.

43. Objective: The students will describe the process of sea-floor spreading.

44. Mid-Ocean Ridges • Since the mid-1900s, scientists have used sonar to study the ocean floor. Sonar is a device that bounces sound waves off underwater objects. The longer it takes the sound to bounce back, the farther away the objects are.

45. Mid-Ocean Ridges • Using sonar, scientists found long mountain ranges on the ocean floors. Scientists call the mountain ranges mid-ocean ridges. Mid-ocean ridges run through the middle of oceans. • In a few places, mid-ocean ridges poke above the surface and form islands. Iceland is the top of a mid-ocean ridge in the North Atlantic Ocean.

46. Mid-Ocean Ridges

47. What is Sea-Floor Spreading? • Sea-floor spreading is a process that slowly adds new rock to the ocean floor. Scientist Harry Hess came up with the idea of sea-floor spreading in 1960. • Here is how sea-floor spreading works. In the center of the mid-ocean ridge, melted rock pushes up through cracks in the ocean floor. The melted rock pushes older, solid rock away from both sides of the ridge. The melted rock cools and forms new solid rock at the center of the ridge.

48. What is Sea-Floor Spreading? • This process keeps repeating. Slowly, the ocean floor is pushed farther and farther away from both sides of the mid-ocean ridge. At the same time, new rock keeps adding to the ocean floor in the center of the ridge. Sea Floor Spreading (4 min.)

49. Objective: The students will describe and provide evidence of the process of sea-floor spreading.

50. Evidence for Sea-Floor Spreading • In the 1960s, scientists tried to find evidence of sea-floor spreading. They found evidence from three sources. The three evidences are evidence from molten material, magnetic stripes, and drilling samples.