When pulled, viscous liquids stretch into ligaments that thin and then break into droplets. In this video, researchers investigate how these ligaments break up, depending on their composition. The initial views show the break-up of a water-glycerol ligament (Image 1) and an oil ligament (Image 2). By placing a water droplet inside oil, the researchers got quite different results, including oil-encapsulated droplets (Image 3). The technique could be useful for making compound droplets, even with more than two components. (Image and video credit: V. Thiévenaz and A. Sauret)
Richard Bready
Study of droplet separation calls to mind the dripping faucet experiments on chaos:
https://robshaw.net/publications/martien1985.pdf
and raise the question, how properties in experiments of that sort would vary with different viscosities. This might be suitable lab work for high school students. Or maybe it’s been done?