  A soap bubble is a metastable object that eventually breaks. Indeed, the
soapy water film thins until rupture, due to drainage and evaporation. In our
experimental investigations, floating bubbles at the surface of a liquid bath
have been considered. Their lifetime has been measured and reported with
respect to their radius. Large bubbles last longer than small ones. Moreover,
small bubbles have more predictable lifetimes than large ones. We propose a
general equation for that lifetime, based on the lubrication theory. The
evaporation is shown to be an essential process which determines the bubble
lifetime.

Fluid Dynamics