How Aurora Generate Electrical Currents on the Earth Part II Pushing this switch completes the electrical circuit that supplies
electrical current from the battery to the coil of wire that surrounds the
magnetic compass. This electrical current will create a magnetic field so
much stronger than the earth's magnetic field that the compass ball will
quickly rotate and align itself with the created magnetic field.
If the ball does not seem to change position when you push the switch there
are three possible problems. First, you may be holding the compass so that
when the switch is pushed the magnetic field generated is in the same
direction as the earth's natural magnetic field. While holding the unit in
the outstretched palm of your hand turn to your left about ninety degrees
and push the button again. Second, if the compass ball still doesn't
quickly rotate try a new battery. The coil uses very little electricity
when the switch is pushed so the battery should last several months. Third,
if the instrument still does not work, the battery may have become
magnetized because it got too close for too long to the cow magnet that will
be used in the second half of this demonstration. Try a new battery.
The magnetic field generated by the changing electrical currents in the
aurora travel quickly to the surface of the earth. Scientists monitor the
magnetic field of the earth and the disturbance of the earth's magnetic
field by aurora with an instrument called a magnetometer. Using the
magnetometer it is possible even during the daytime to determine whether
aurora are taking place. Back to Aurora Main |
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