Simulating the continental drift

2008/09/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Geologia

Some physicists at the University of New York wanted, through a simple experiment, to explain why the continents are separated from the Earth and then reunited every hundreds of millions of years.

They simulated the effect of the variable thickness of the earth's surface on the convection current of the lower mantle. A three-liter tank was filled with water and glycerin, heating the liquid with a hot sheet under. Once the water was heated and the convection current formed, with balls of about three millimeters of diameter, they covered half the surface of the bottom.

Due to the convection current generated by the heat, the balls were piled to one side of the tank. In this way, the balls prevented the passage of the heat emitting the sheet, which allowed the side that did not have of it to have the greatest force to heat the liquid, which caused a change of sense of the current. Then the balls began to push over and began to move up to the other end of the boat. There the process was resumed.

Physicists have said that something similar occurs on Earth, that the terrestrial surface of the continents is much thicker than that of the oceans. In this way, the continents would have the same influence as the balls of the experiment, which would hinder the heat emitted by the terrestrial mantle. This would cause periodically the currents of the mantle to change their sense, which would cause a displacement of the continents.