Surface Tension Gradients Induced by Temperature: The Thermal Marangoni Effect

This article presents a simple experiment to demonstrate the motion of liquids induced by surface tension gradients generated by local heating. Changes in temperature are produced by bringing a heat source (soldering iron) close to a thin liquid film in a Petri dish, where the motions are easily observable owing to the rupture of the film. The experiment is easy to perform, and the visualization of the effect can facilitate the introduction of surface tension gradients. The use of other heat sources and some of the possible variations of this experiment are also mentioned. Find this demonstration and others in the DigiDemos area of the JCE Digital Library.