Book 21, Question 51
Why Is Earth Like a Giant Bar Magnet?
Earth has a magnetic field that looks a lot like the field around a giant bar magnet. It has a north end and a south end, and it reaches every place on the planet. But there is no giant magnet hiding inside!
More fun facts
- Earth acts like a giant bar magnet with a magnetic north and south pole.
- These magnetic poles are not in the same place as the geographic poles.
- Earth's magnetism comes from molten iron moving in the outer core.
- The core is far too hot to be a permanent magnet, so it must keep making its field.
- Permanent magnetism can't last above about 650 degrees Celsius (1,200 degrees Fahrenheit).
- Some rocks in Earth's crust are permanently magnetized.
Sources: BBC, U.S. Geological Survey
Questions kids ask
Is there a giant magnet inside Earth?
Not a solid one. The core is too hot to be a permanent magnet, so moving molten iron makes the field instead.