1. Earth

2. What do you think it means when people say the Earth is like an onion?
Think! Think of an answer and write it in your notes.
Pair! Turn to the person next to you and share your ideas.
Share! Share your partner’s idea with the class.

3. The Earth is like an onion because it contains many layers!
The atmosphere – a thin layer of air that surrounds the Earth
The hydrosphere – all water and ice that covers the Earth
The lithosphere – the crust (land) that covers the Earth.

4. The Lithosphere Crust Mantle
What we live on.
Made up of minerals that contain oxygen, silicon, and smaller amounts of other elements.
Mantle
liquid that the crust floats on.
Moves the continents, causes earthquakes and volcanic eruptions, and forms mountains.
Outer Core – liquid made of iron and nickel
Inner Core – solid
The Lithosphere

5. The Hydrosphere
Earth is the only planet with abundant liquid water on the surface.
Water is essential for life on Earth.
About 71% of the Earth is covered in water, most of which is in the oceans.
Only about 3% of Earth’s water is safe to drink!

6. The Atmosphere The air that surrounds Earth
Protects us from small debris from space.
Made up of:
Nitrogen (78%)
Oxygen (21%)
Other gases (1%)
Also contains water vapor, carbon dioxide, water droplets, dust, and chemicals released from volcanoes, fires, and human activities.

7. Atmospheric Layers Troposphere Stratosphere Mesosphere Thermosphere
Closest to Earth’s surface
Where weather occurs
Stratosphere
Ozone layer helps absorb harmful ultraviolet radiation from the Sun
Mesosphere
Thermosphere
The atmosphere traps heat from the Sun to warm the Earth. This is called the greenhouse effect and is necessary for life on Earth.
Atmospheric Layers

8. Magnetic Field The area that surrounds a magnet.
Earth has one as if there were a giant bar magnet buried inside it.
Currents of magma moving inside the core are thought to create these magnetic fields.
A compass will always point North because the needle in the compass is attracted to the North magnetic pole.

9. Van Allen radiation belt
Discovered by the American satellite, Explorer 1
Acts like a shield, protecting us from particles from the Sun. Held in place by Earth’s magnetic field.

10. How does Earth compare to the other planets?
What is wrong with this picture?
(Answer this on your notes sheet. Think about the lab we did on Friday and compare it to this picture.)

11. How does Earth compare to the other planets?
Is this picture more accurate? Why or why not?

12. How does Earth compare to the other planets?
This is an accurate comparison of the rocky inner planets and the dwarf planet Pluto.

13. How does Earth compare to the other planets?
Remember how big Earth looked in the previous picture? This is a picture of the inner planets compared to the outer planets.

14. How do you think the size of the planets compares with the size of the Sun?

15. Could there be other planets like Earth?
For life to exist on another planet, what do conditions on that planet need to be like?
Any star in any galaxy could have planets revolving around it…how do we figure out if these planets can support life?
Searching for life around other stars
Kepler-22B