1. The Earth’s Magnetic Field

2. Earth is like a bar magnet

3. The Earth’s Magnetic Field protects us from Solar Wind
A stream of electrically charged particles that could destroy life on earth

4. Interaction between solar wind and earth’s atmosphere can be seen near the north & south pole in the form of Aurorae

5. What causes our Magnetic Field?
The Dynamo Theory:
Rotation of the earth causes liquid rock in outer core to spin
Moving electrons from the iron & nickel creates an electric current
Electric currents produce magnet fields (Faraday’s Law)

6. To make an electromagnet: you only need flowing electrons that surround an iron core

7. The magnetic field changes through time, due to changes in the flow of molten currents

8. How do we know it changes?
Below a certain temperature, rocks will “record” the direction of the magnetic field