1. Science Final Unit Earth’s Crust And Resources

3. Structure of the earth

4. Definitions: Crust - the rigid, rocky outer surface of the Earth, composed mostly of basalt and granite. The crust is thinner under the oceans.

5. mantle - a rocky layer located under the crust - it is composed of silicon, oxygen, magnesium, iron, aluminum, and calcium. -Convection (heat) currents carry heat from the hot inner mantle to the cooler outer mantle.

6. outer core - the molten iron-nickel layer that surrounds the inner core.

7. Inner core - the solid iron-nickel center of the Earth that is very hot and under great pressure.

8. The Theory of Plate Tectonics According to the theory of plate tectonics, the lithosphere (the upper mantle and crust ) is broken into large areas called plates These plates are constantly moving

9. The movement of these plates is away from the ocean ridges and towards the deep trenches.

10. Ridge

11. Trench

12. Earthquakes and Volcanoes tend to be more common where the plates meet.

13. What happens when plates meet? The edges where plates meet are called boundaries These boundaries look different depending on whether plates are moving away from each other, into each other or alongside each other.

14. Plates moving away from each other !! 1) A Diverging boundary is where plates are moving away from each other. –Ex) Mid-Atlantic Ridge At diverging boundaries, lava flows from the ridge to form new oceanic crust

15. Mid-Atlantic Ridge

16. Plates moving into each other 2) Converging boundaries, plates come together. When plates come together we feel earthquakes and see mountains and volcanoes form There are two types of Converging boundaries:

17. Type 1: Trench forming boundaries Trench forming boundaries occur when oceanic plates collide with continental plates

18. The thinner oceanic plates are forced under the thicker continental plates and a trench is formed

19. As a result of the plates colliding, earthquakes are felt. As well, as the oceanic crust is forced down, it melts and forms molten rock. The molten rock often rises to the surface, forming volcanoes

20. Type 2: Mountain forming boundaries Mountain forming boundaries occur when two continental plates collide They crush together to form huge mountain ranges.

21. Plates that move alongside each other. 3) Transform boundaries, plates slide along beside each other. This sliding does not take place smoothly and earthquakes often occur at these boundaries Ex) The west coast of Canada

22. Earthquakes An earthquake is a shaking of the Earth caused by a sudden breaking of large blocks of rock in the Earth’s crust. Most earthquakes occur at the boundaries between plates; however, earthquakes can occur in the middle of plates, Faults are cracks in the Earth’s crust where movement occurs.

23. How do earthquakes occur!!! 1) The plates collide or a fault forms. 2) Rocks start to break. –The point below the surface where rocks first break is called the Focus 3) This sudden breaking of rocks releases waves of energy called Seismic Waves. 4) These waves cause damage and change the Earth’s surface. –Scientist use these waves to measure earthquakes.

24. How do earthquakes occur!!! 5) These waves also cause the shaking you feel in an earthquake 6) The point on the surface directly above the focus is called the epicentre –The epicentre helps determine the location of an earth quake

25. Earthquake Assignment Your assignment is to pick one of the worst earthquakes of all time and answer the following questions: –1) Where and when did it occur? –2) How big was it? –3) What type of boundary was it ? –4) Interesting facts..

26. Measuring Earthquakes Read p. 275 What is the Richter scale (be sure to state where the name came from and how it works) Define seismograph and seismogram

27. Measuring Earthquakes The Richter scale was developed by Charles Richter to measure earthquakes The scale starts at 0 and goes up by 1’s Each step up the scale is an increase of 10x the magnitude –Ex) 3 on the Richter scale = 10 x 10 stronger then level 1

28. A seismograph is a device that measures and records the motion of the ground caused by earthquakes and seismic waves Seismogram: A graphic illustration of the vibrations “felt” by the seismograph

29. Seismograph

30. Building mountains Mountain ranges are a series of mountains A mountain is a part of the earth’s surface that is much higher than the land around it. Mountain’s are formed 3 different ways. –Folding –Faulting –Volcanic activity

31. Folding mountains

32. Fault Block mountains

33. Volcanic mountains ( Mt. Saint Helens)

34. Rocks and Minerals Rocks: a substance made of one or many minerals Minerals: a pure substance that forms naturally as a solid in the Earth

35. Classifying Minerals Minerals are classified by their chemical composition (by what chemicals are in them) 5 minerals combine to form most of the rocks in the Earth’s crust. These minerals are: –Calcite –Quartz –Feldspar –Mica –Hornblende

36. Classifying Rocks To identify rocks you need to identify the minerals they contain. Minerals can be identified by their properties (features they have)

37. Classifying Rocks The four main properties for determining minerals are: –Colour: What colour is it? –Lustre: The way the surface of a mineral looks in the light. –Streak: The colour of powder a mineral leaves behind when it is rubbed against a rough surface –Hardness: A hardness scale is used to test minerals

38. Igneous Rock Igneous is Latin word meaning “iginis” meaning fire. Formed by magma. May be warm or cold on the surface On land or beneath water it is called lava. You can tell them apart by pegmatite and basalt, one cools on land and one deep inside the earth.

39. Sedimentary Rock A rock with many layers. Mainly Formed from dead animal shells. The more the sediments pile up they get compressed by the weight of the other sediment. This forces the sediments closer together. After a while it forms hard rock

40. Metamorphic Rocks Changing shapes It’s a Greek name These rocks start out as sedimentary or igneous rock Its heat and pressure causes changes It may even have caused the mineral grains to melt slightly, reform and get harder

41. Identifying Rocks Dichotomous key activity

42. Mining Page 300-301 –Define ore and mining

43. How rocks form and change over time. There are a number of factors that cause change in rocks. The following are some of these factors: 1) Weathering- weathering is the process that wears down rocks and other objects

44. Weathering There are three types of weathering: –Mechanical weathering: When rocks are broken apart by physical forces, such as water or wind. –Chemical weathering: When water in the air combines with chemical substances in the air to form acids. Rocks exposed to these acids are broken down

45. Biological Weathering: When living things wear away rocks. –Ex) Tree roots growing through rocks or pavement.

46. 2) Erosion: The movement of rock materials and soil by water, wind or ice. –Rivers and moving bodies of water are forces of erosion that gradually break down rock –Landslides are forces of erosion that happened very quickly

47. Rock cycle Handout and Rock cycle Diagram

48. Rock Cycle Diagram

49. Soil Soil is a mixture of rock fragments, minerals, grains and organic material. –Organic material is made up of once living things and waste from living things. When organic material decays completely it is called Humus –Humus gives soil a rich, dark colour and keeps soil moist by absorbing water

50. Soil The spaces between rock fragments, minerals, grains and organic material are called pores. –Pores, allow water and air into the soil so the plants can grow –The best soils have just the right combination of minerals, organic matter and pores (Fertile soil)

51. How Soil Forms Activity

52. Characteristics of Soil Scientists use the following characteristics to describe soil: 1)Texture: a description of how smooth or sharp the grains of soil are and how big they are. 2)Pore Size: how easily water and air move through the soil. 3)Air and Water Capacity

53. 4) Nutrient Content -Nutrients are the essential materials living things need to survive 5) Depth of the soil

54. Soil Conservation Read pages 336-338 Discuss Communicate Questions together

55. Activity

56. How we affect the world around us. As a class, read pages 342 -345 Discuss problem solver together

57. Using Earth’s resources Discuss pages 346-347