The Earth As a Magnet:
1. Describe the magnetic poles and magnetic field of earth.
2. Distinguish between the geographic and magnetic poles.
3. Explain the behavior of compasses.
earth as a magnet:
earth behaves as a giant bar magnet.
It has N
& S poles
Magnetic north is located in the geographic south and vica-versa
magnetic fields are possibly created by the rotation of Earth's inner core and are strongest at the poles
region that contains the earth’s magnetic field is called the magnetosphere
geographic N & S poles are not exactly the magnetic poles.
The angle created between them is called the magnetic variation or
The orientation of Earth's magnetic field is not fixed. It has switched more than 20 times and has even been switched off for 10 - 20 thousand years.
Magnetism is due to the motion (spin) of electrons. As electrons spin on their axes, they create both an electric and a magnetic field.
atoms have paired electrons in a spin anti-spin configuration.
The two cancel ea. other out.
unpaired electron contains an electric (magnetic) field.
metals (Fe, Ni, & Co) contain unpaired electrons. These materials naturally contain low levels of magnetism and are
easier to charge.
electric (magnetic) fields become lined up, the metal becomes magnetized.
rearrangement of magnetic fields creates what is called a magnetic domain.
charging is not permanent as
the domains eventually move back to their original position and the material looses
its magnetic properties.