So I have a fascination for older science books. Watch out! They are not always accurate. The How and Why Wonder Book of Magnetism states that the compass needle points north because it is attracted to the large deposit of lodestone at the North Pole. For those who haven't spent the last two months reading science history, lodestone was what magnetic stones were called.
It turns out that the most likely explanation for the magnetic field of the Earth is the molten core. This guy really wants to make sure, though. So he's doing what every scientist does to be sure--he's going to experiment. By building a model. A model of the planet, actually. Neatorama, again.