Double-Diffusive Instability
Jewell students used Schlieren imaging to view the otherwise transparent double-diffusive instability at the interface of a sucrose solution and a solution of salt water in a vertical Hele-Shaw cell.  The thickness of the flow was only 0.8 mm.  The flow cell used was constructed by faculty and students at William Jewell.


Saffman-Taylor Instabiity
This video shows the Saffman-Taylor instability imaged using fluorescence of the molecular probe pyrene. Silicone was injected into a highly viscous polymer (Lauryl Acrylate) containing pyrene. The flow was imaged by Jewell students using a Nikon D7000 camera monitoring the fluorescence emission during ultraviolet irradiation. Jewell students will be further developing this technique with the goal of in situ measurement of viscosity during reactive flows.
Neutralization Reaction
This video shows the chemically-driven instability discovered by De Wit and colleagues at the University of Brussels.*  Aqueous hydrochloric acid is injected above the base NaOH in a Hele-Shaw cell (two glass plates separated by less than a mm).  The reaction between the two leads to salt plumes rising.  All components of the reaction are completely transparent.  The video was recorded by William Jewell Physics students using Schlieren imaging.*C. Almarcha, Y. R’Honi, Y. Decker, P. Trevelyan, and A. De Wit, “Convective Mixing Induced by Acid-Base Reactions” J. Phys. Chem. B115 (2011) 9739-9744.