The patterns formed by droplets falling through a different liquid was studied over a century ago. We perform similar experiments here, whereby droplets of naphthenic oil approximately 3 mm in diameter are released from several heights into a container filled with isopropyl alcohol. The oil is denser than and miscible in the alcohol, which results in the drop descending and eventually diffusing. Images are captured with an SLR camera looking through the alcohol onto a black background with white light projected on either side. The difference in index of refraction between the oil and alcohol cause the edges of the oil droplet to appear bright. The full study can be found in Physics of Fluids.
Our image from the study was featured in the Spring 2012 issue of BYU Magazine.