SELF-ROTATION OF A CAMPHOR SCRAPING ON WATER - NEW INSIGHT INTO THE OLD PROBLEM

The translational and rotational motion of a camphor scraping at an ai r/water interface was investigated. The characteristics of the rotatio n depended on the temperature, surface tension, and the chemical struc ture of the camphor derivative. The direction of rotation, either cloc kwise or counterclockwise, is determined by asymmetry in the shape of the solid camphor scraping, The essential features of the motion of a camphor scraping were reproduced by a computer simulation. The driving force on this motion is believed to be the spatial heterogeneity of t he camphor layer at the air-water interface.