1. Ch. 9: Physical Processes
Vocabulary:
landforms, mountain, hill, plateau, plain, plates, plate tectonics, erosion, weathering

2. The Ring of Fire
The ring of Fire is a circle around the Pacific Ocean where 90% of the world’s earthquakes and volcanoes happen.
Earthquakes and volcanoes are two of the ways that the Earth changes under our feet, but there are many more.

3. Earth’s Surface Water covers 75% of the Earth’s surface.
The other 25% is covered by land.
Land is broken into pieces called landforms.
There are many
different types of
landforms that make
up the surface of the
Earth.

4. Landforms
Mountains: Landforms that rise above sea level, that are broad at the base and narrow at the top.

5. Landforms
Hills: These landforms are similar to mountains, but smaller, and have rounded tops

6. Landforms
Plateaus: Landforms that are like mountains, and hills, but flat on top with at least one side having a steep slope.

7. Landforms
Plains: a large area of flat, or gently rolling land.

8. Volcanoes, Earthquakes, and Shifting Plates
Earth’s outer layer is the crust.
The crust is broken into big pieces called plates.
The plates float on top of the next layer of the Earth that is made of magma (liquid/soft rock).
Since the plate move slowly most of the time, we can‘t see it happening and have named the theory plate tectonics.

9. Volcanoes, Earthquakes, and Shifting Plates
Since the plates are floating they often run into each other.
Where two plates meet it is called a fault line.
This happens in three ways:

10. Ways Plates Interact
Plates move toward each other, thickening the crust, and forming mountains.

11. Ways Plates Interact
Plates move away from each other forming trenches.

12. Ways Plates Interact
Plates push past each other.

13. When Plates Move
Plates that push past each other usually slide smoothly, but occasionally they get caught on rocks far beneath the surface on the other plate.
When this happens pressure builds up until the rocks slip, or the plate breaks them.
After the plate is freed it moves very quickly and causes vibrations in the ground.
We call those vibrations earthquakes.
Earthquakes can cause a lot of damage to people and property.

14. When Plates Move
When earthquakes happen underwater, they can cause a vibration to run through the water creating a large wave that is capable of flooding hundreds of
acres.
These waves are
called tsunamis, or
tidal waves.

15. When Plates Move
Sometimes when plates rub against each other it weakens the rock in the plates, allowing magma to push up through to the surface of the Earth.
When this happens the magma escaping to the surface is called an eruption.
The magma above the surface of the Earth is now called lava.
A new volcano is born.
When volcanoes erupt more than lava is spewed out, volcanoes also throw out clouds of ash and poisonous gasses.

16. Erosion and Weathering
Erosion is a process by which wind, ice and rain break down big rocks into tiny rocks, or soil.
Weathering is the process where wind or water moves around rocks or soil.
The Appalachian Mountains used to be as tall as the Rocky Mountains, when they were first formed, but erosion and weathering have made them smaller and more rounded.
Appalachian Mountains
Rocky Mountains

17. Questions about Chapter 9
How are new mountains made?
What 3 things cause erosion?
What do Earth’s plates float on?
How much of the Earth is covered in water?
What are the pieces that the crust of the Earth is broken into called?
What 3 things do volcanoes spew when they erupt?