The behavior of multiphase systems in low gravity

The motion of drops and bubbles due to interfacial tension gradients is studied. It is noted that, when a drop or bubble is inserted into a fluid possessing a temperature gradient, the resulting gradient of interfacial tension will, through viscous traction on the neighboring fluid, cause it to move. In response, the drop will propel itself in the direction of the pole with the lower interfacial tension. This phenomenon, thermocapillary migration, is discussed in detail.