磁界中の電気化学反応によるイオン流から生じる液回転によるフレミングの左手の法則の視覚化 Visualization of the Fleming's Left Hand Rule Using the Vortex Motion Caused by Motion of Ion Species During Electrochemical Reactions in the Magnetic Field
To visualize the Fleming’ s left hand rule using ion species as charged particles in aqueous solution, the discharge reactions of the Daniel’ s cell and the redox reaction of Fe<SUP>2+</SUP>/Fe<SUP>3+</SUP> were carried out under vertical magnetic field. A copper tube was united with a circular transparent acryl resin plate, which was employed as an electrolytic cell. A zinc or carbon rods was centrally inserted into the acryl resin plate of the cell. The cell was placed on a permanent magnets (neodymium and ferrite magnets) or an originally prepared electromagnet. The geometrical arrangement was shown in Fig. 5. The cell was filled with electrolyte solution : 0.1 mol/L CuSO<SUB>4</SUB> aqueous solution for the discharge reaction of the Daniel’ s cell and 0.1 mol/L H<SUB>2</SUB>SO<SUB>4</SUB> aqueous solution containing 0.1 mol/L FeSO<SUB>4</SUB> and 0.1 mol/L Fe<SUB>2</SUB> (SO<SUB>4</SUB>) <SUB>3</SUB> for the redox reaction of Fe<SUP>2+</SUP>/Fe<SUP>3+</SUP>. The vortex motion of the electrolyte solutions originated from the Lorentz’ s force was clearly observed as soon as the cell reactions and the redox reaction took place under the vertical magnetic field caused by the electromagnet. The vortex motion visualized Fleming’ s left hand rule. The magnitude of the vortex motion was estimated by the rotation rate (rotation number a second) . The higher the rate became, the larger the electrolytic current of the redox reaction of Fe<SUP>2+</SUP>/Fe<SUP>3+</SUP>or the stronger the magnetic field was, which showed the quantitative relationship of the Lorentz’ s force. On the other hand, for the Daniel’ s cell, the rate decreased accompanying a decrease of the discharge current in time. The experiment was introduced for college students as estimators.
工学教育 59(4), 92-98, 2011-07-20