There is no direct way to observe the interior of the Earth. Much is known already about its different physical and chemical properties by careful study of how seismic waves propagate through the interior. The so-obtained picture of the Earth's interior includes a plausible explanation of how the magnetic reversals give rise to the magnetic anomalies that appear on the ocean ridges. These magnetic reversals are a characteristic feature of the dynamo process that is believed to sustain the geomagnetic field. Computational models are discussed along with some experiments that are being performed here at the University of Maryland, particularly the 3m project, and other experiments in other labs around the world.