  In the Leidenfrost effect a small drop of fluid is levitated above a
sufficiently hot surface, on a persistent vapor layer generated by evaporation
from the drop. The vapor layer thermally insulates the drop from the surface
leading to extraordinarily long drop lifetimes. The top-view shape of the
levitated drops can exhibit persistent star-like vibrations. I extend recent
work [Burton et al. PRL 2012] to study the bottom surface of the drop using
interference-imaging. In this work I use a high-speed camera and automated
image analysis to image, locate and classify the interference fringes. From the
interference fringes I reconstruct the shape and height profile of the rim
where the drop is closest to the surface. I measure the drop-size dependence of
the planar vibrational mode frequencies, which agree well with previous work. I
observe a distinct breathing mode in the average radius of the drop, the
frequency of which scales differently with drop size than the other modes. This
breathing mode can be tightly coupled to a vertical motion of the drop. I
further observe a qualitative difference in the structure and dynamics of the
vertical profile of the rim between large and small drops.
