Transcript Earth Science

The Earth’s Magnetic
Field
Earth is like a bar magnet
The Earth’s Magnetic Field
protects us from Solar Wind
►A
stream of
electrically
charged
particles that
could
destroy life
on earth
►Interaction
between solar wind and
earth’s atmosphere can be seen
near the north & south pole in the
form of Aurorae
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)
►To
make an electromagnet: you
only need flowing electrons that
surround an iron core
►The
magnetic field changes
through time, due to changes in
the flow of molten currents
How do we know it changes?
►Below
a certain temperature, rocks
will “record” the direction of the
magnetic field