Thermo-magnetic Effects in Liquids

Abstract

RECENTLY, several authors^1–7 have investigated the effect of a magnetic field on thermal convection in electrically conducting liquids. In this communication we present the results of a simple experiment on the effect of the magnetic field on the rate of cooling of two liquids, namely, mercury and water. A glass tube (length 20 cm. and diameter 4.2 cm.) was placed on a frame suspended between the pole-pieces of a large electromagnet (type ADL Cambridge, Mass, U.S.A.). The frame was made of wood and brass rods, and was completely isolated (thermally) from the pole pieces of the magnet. The glass tube, filled with mercury up to a height of 15.7 cm., was heated and then allowed to cool in a magnetic field of about 23,000 cersteds and without the magnetic field. The cooling curves for both cases are shown in Fig. 1. These curves clearly show that the rate of cooling for mercury is faster in the magnetic field. The experiment was later repeated also with water, and a similar effect on the rate of cooling was observed (Fig. 1).