1. Earth has several layers
1.1 Notes
Earth has several layers

2. Think About…
What causes a material to sink or float?

3. Think About…
Vegetable oil/water/alcohol demo

4. Watch…

5. Density
Which has more mass?

6. Density
Density depends on both the size of the object and the matter contained inside

7. Density Density is the amount of mass per unit volume of a substance.
The bricks are more dense than the feathers.
The water bottle is more dense than the balloon.

8. Density

9. Density
Density depends on the material an object is made from, NOT its size.

10. Sinking and Floating
An object will float if the density of the object is LESS than the density of the liquid it is in.

11. Sinking and Floating
An object will sink if the density of the object is MORE than the density of the liquid it is in.

13. Think About… What is more dense? Coke vs. Diet Coke
Water vs. Salt Water

14. Earth is made up of materials with different densities
4.6 billion years ago, Earth formed as material collided and stuck together.
The planet grew larger as more and more material stuck together.

15. Earth is made up of materials with different densities
Over time, denser materials such as iron and nickel sank toward the center of the Earth, and less dense materials rose to the surface.

16. Earth is made up of materials with different densities.
Slowly, Earth’s main layers formed-the core, the mantle, and the crust.

17. Earth’s layers have different properties
How can we know what Earth’s interior is like? No one has seen it.

18. Earth’s layers have different properties.
Scientists study the energy from earthquakes or underground explosions they set off.
This energy moves slower through less dense materials or liquids and faster through denser materials or solids.

19. Core, Mantle, Crust
The core is Earth’s densest region and is made up of two parts.

20. Core, Mantle, Crust The inner core is a ball of hot solid metals.
The pressure from the layers above is so great that the inner core is a solid despite the fact that it is extremely HOT!

21. Core, Mantle, Crust
The outer core is a layer of liquid metals that surrounds the inner core.

22. Core, Mantle, Crust
The mantle is Earth’s thickest layer-about 2900 km (1700 mi)!

23. Core, Mantle, Crust
The mantle is hot rock that is less dense than the core.
The very top part of the mantle is cool and rigid.

24. Core, Mantle, Crust
The crust is a thin layer of cool rock.

25. Core, Mantle, Crust There are two basic types of crust:
Continental crust-includes the continents and major islands
Oceanic crust-includes all the ocean floors

26. Lithosphere and Asthenosphere
Earth’s crust and the very top of the mantle together form the lithosphere.
Greek prefix litho=“stone” or “rock”

28. Lithosphere and Asthenosphere
The lithosphere sits on top of the asthenosphere-a layer of hotter, softer rock in the upper mantle.

29. Lithosphere and Asthenosphere
The asthenosphere is soft enough to flow slowly, like hot tar.
Imagine the lithosphere as solid pieces of pavement resting on hot tar.

30. The lithosphere is made up of many plates
The lithosphere does NOT form a continuous shell around Earth.

31. The lithosphere is made up of many plates.
The lithosphere is broken into many large and small slabs of rock called tectonic plates.

32. The lithosphere is made up of many plates
We do not now how or when these giant plates formed.

33. The lithosphere is made up of many plates.
Most large tectonic plates include both continental crust and oceanic crust.
Remember, when you’re looking at a map, you’re only seeing the part of Earth’s crust that rises above the ocean.

34. Think About… All of this information leads us to 2 questions.
Have the continents always been where they are today?
If not, how did they move to their present positions?
To be continued…

35. Review Which of the following best describes Earth’s mantle?
The densest of Earth’s layers
The home of all life on Earth
The thickest layer of hot rock
The thinnest and hottest layer

36. Review 2. Tectonic plates make up Earth’s lower mantle lithosphere
asthenosphere
inner core

37. Review
3. Density is a measure of the amount of A. matter in a given volume B. volume that a substance takes up C. space between objects D. pressure in a given volume