MICROSCOPY: 2D Oil Film Video    (Go to Stills)


Thin film of volatile oil on a water surface.  Oil drop added to 3mm deep water layer in 3cm x 3cm black "pan".  Oil thins out and evaporation occurs in isolated shallow pools only a few microns deep.  Coalescence into thicker and rounder droplets provides more volume per unit surface area, which resists evaporation.  Very thin regions show interference colors and motions.  The complex microscopic fluid dynamics are relevant to the longevity of fuel spills.   Reflected light differential interference contrast ('DIC' or 'Nomarski') microscopy.