The image to your right may look like a fine art print of an ocean scene at night, but it’s actually just a close-up of some dried Glenlivet 162, or for those of you who aren’t avid alcohol connoisseurs – it’s simply a photo of whiskey.
Maybe “simple” is not the best word to describe the chemical process that takes place, but the discovery that whiskey can make these beautiful images had a humble beginning.
Professional artist and photographer Ernie Button started creating photos of the patterns formed after letting a drop or two of whiskey dry at the bottom of a glass, which resulted in these clear and rhythmic images.
Though he loved the aesthetic value, Button wanted to understand why the images looked the way they looked.
He then reached out to Howard Stone and his Complex Fluids Group at Princeton University’s Department of Mechanical and Aerospace Engineering, where they focused on understanding the composition of whiskey in hopes that it would tell why these patterns were being created.
This from Discovery News:
To study the flow patterns and concentration in the solution, as well as the final dried deposits from suspended particles, a postdoctoral researcher in Stone’s lab, Hyoungsoo Kim Kim, and colleagues used video microscopy of drying droplets of actual whiskey and compared it to video microscopy of an alcohol-water solution representative of whiskey. Typical whiskies are 40 percent by volume ethanol (alcohol) and 60 percent by volume water.
What they found is that as whiskey beings to evaporate, the ethanol concentration increases, which thereby increases the mobility of the receding contact line. With this contact line receding, the groups of particles from the preparation process are drawn along with it and deposited in radical patterns.
All of this demonstrates something known as the Marangoni Effect, which is the mass transfer along an interface between two fluids due to surface tension. In this case, alcohol and water.
“The alcohol-water solution shows circulation flow patterns (triggered by the Marangoni Effect), which occur during drying and influences patterns formed in evaporating whiskey solutions,” Kim noted. “Deposits in the actual whiskey come from a small amount of inherent raw materials present from the preparation process.”
Want to see what other surprises the amazing world of microscopy holds? Check out our “25 Years of Scanning Electrochemical Microscopy” issue of Interface. Plus, it’s 100 percent Open Access!
