Langmuir 1989, 5, 447-451 method involving a significant volume of solution.
Experimental Section The MBPM apparatus and the cell have been described previously.2 The stroboscope used was a simple Pasco Scientific (Hayward,CA) Model SF9211. Photographs were taken without synchronization by using a 35-mm reflex camera and a reversed 55-mm lens on a 37-cm extension tube. For photographing, the cell was a spectrophotometer cuvette having two round windows separated by 1cm. It was placed close to an optical window sealed into the protecting bell jar.z Despite this protection the bubbling was not sufficiently regular to permit a complete stopping of the motion. The photographs of Figure 1represent a selection from about 100 slides taken over several days at various bubbling rates. Conclusion The conventional maximum bubble pressure method of measuring surface tension provides accurate surface tension data and can show the evolution of bubbles as the
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bubble ages over a wide span of time. The processes involved in that aging are, however, complicated, and a quantitative interpretation in terms of an equivalent age of the surface, or the like, is complicated by convection for both short and long times. At very short times (
