The key for anyone wanting to make a big splash is pressure—of the atmospheric kind, that is. Normally, when a liquid droplet hits a surface, it spreads into an undulating puddle that rips apart into a splatter. Seeking to control splashing, University of Chicago physicists released alcohol drops in a vacuum chamber onto a smooth, dry glass plate and recorded the results with a camera shooting 47,000 frames per second. At roughly one-sixth normal atmospheric pressure, splashing completely disappeared; droplets just pancaked without visible undulations. The investigators suspect that fallen drops splatter because gas pressing on them destabilizes their outward spread. These findings, presented at the March meeting of the American Physical Society, could help control splashing in fuel combustion and in inkjet printing.
This article was originally published with the title "No-Splash Liquid" in Scientific American 292, 6, 36 (June 2005)