24.2. Earth as a Magnet http://www.ck12.org
Benefits of Earth’s Magnetic Field
Earth’s magnetic field helps protect Earth and its organisms from harmful particles given off by the sun. Most of the
particles are attracted to the north and south magnetic poles, where Earth’s magnetic field is strongest. This is also
where relatively few organisms live.
Another benefit of Earth’s magnetic field is its use for navigation. People use compasses to detect Earth’s magnetic
north pole and tell direction. Many animals have natural "compasses" that work just as well. Birds like the garden
warbler inFigure24.16 use Earth’s magnetic field to guide their annual migrations. Recent research suggests that
warblers and other migrating birds have structures in their eyes that let them see Earth’s magnetic field as a visual
pattern. You can learn more about animals and Earth’s magnetic field, including the potential effects of magnetic
field reversals, at this URL: http://www.pbs.org/wgbh/nova/nature/magnetic-impact-on-animals.html.
FIGURE 24.16
The garden warbler flies from Europe to
central Africa in the fall and returns to Eu-
rope in the spring. Its internal "compass"
helps it find the way.KQED: Illuminating the Northern Lights
Northern California residents may not be able to see the northern lights like people in Alaska can, but Bay Area
scientists are playing a key role in understanding them. Find out more about the spectacular light shows up north
and what scientists at UC Berkeley are discovering about the Earth’s magnetic field. For more information on the
northern lights, see http://science.kqed.org/quest/video/illuminating-the-northern-lights/.
MEDIA
Click image to the left for use the URL below.
URL: http://www.ck12.org/flx/render/embeddedobject/116508