You will now create an outline for your final assignment.
In this lesson you’ve learned that Earth is made of distinct layers within the geosphere, including the crust, mantle, outer core, and inner core. These layers interact, driven by heat from the core, to move lithospheric plates and create earthquakes, volcanoes, and mountains. Through these processes, the Earth’s surface is always changing and shapes the landscapes we see today.
You took notes on almost every page of the lesson, and now it’s time to use them as well as any other evidence presented. You’ll compose your own multimedia project, or write a final essay, in which you describe and summarize your solid understanding of the geosphere by imagining a trip around the world and exploring plate boundaries. Describe your journey, detailing the processes within the Earth, the movement of the plates along the boundaries, and the landforms created.
Use Organize It to outline your ideas. You can review your notes in “My Work” as well as any of the following videos and glossary terms.
| Keyboard Shortcut | Action |
|---|---|
| Space | Pause/Play video playback |
| Enter | Pause/Play video playback |
| m | Mute/Unmute video volume |
| Up and Down arrows | Increase and decrease volume by 10% |
| Right and Left arrows | Seek forward or backward by 5 seconds |
| 0-9 | Fast seek to x% of the video. |
| f | Enter or exit fullscreen. (Note: To exit fullscreen in flash press the Esc key. |
| c | Press c to toggle captions on or off |
Earth is made up of different things.
The non-living things that make up our planet can be separated into three main “spheres”.
Our atmosphere - the gas portion of our planet.
Our hydrosphere - the water layer (oceans, lakes, glaciers, etc).
And our geosphere - the rock component of our planet.
This geosphere isn’t just the solid rock we see from our place on its surface. If we peel back the onion of Earth to its center, there are 4 main layers to the geosphere:
The top layer we call home is the crust - This layer is typically solid rock that varies in thickness and density.
Then there is the mantle- a thick, hot, liquid layer of rock.
Next up is the outer core made of liquid metal, followed by the inner core made of solid metal.
The deeper into the Earth you go, a few general patterns emerge: The pressure increases, the heat increases, and the density increases.
So as much as we’d like to consider ourselves on solid ground, the layers of our planet are always changing beneath our feet.
Organize It!: Your work has been submitted.
| Keyboard Shortcut | Action |
|---|---|
| Space | Pause/Play video playback |
| Enter | Pause/Play video playback |
| m | Mute/Unmute video volume |
| Up and Down arrows | Increase and decrease volume by 10% |
| Right and Left arrows | Seek forward or backward by 5 seconds |
| 0-9 | Fast seek to x% of the video. |
| f | Enter or exit fullscreen. (Note: To exit fullscreen in flash press the Esc key. |
| c | Press c to toggle captions on or off |
Our geosphere - the rock portion of our planet - is made up of layers that quite literally move the Earth under our feet.
The rigid upper portion of our geosphere is called the lithosphere (crust + upper mantle) which is separated into different plates of various sizes, thickness and densities. Below these lithospheric plates is a section of gooey, hot mantle called the asthenosphere.
Powered by the core’s heat, the asthenosphere warms, rises, cools, and sinks again (aka convection currents). And as it does, it moves the plates above it - they collide, slide and pull apart, and the lithosphere is created and destroyed in some geologically awe-inspiring ways.
Where plates collide, mountains form, volcanoes erupt, the crust melts back into the mantle, and earthquakes occur.
When plates slide past each other, we get earthquakes.
And as plates get pulled apart, liquid rock (magma) rises to create new earth (volcanoes) and yes–more earthquakes.
All this is happening slowly. But even at a rate of centimeters per year, these plate boundaries are the scene of some pretty epic earth-making.