Short Sharp Science: 'Liquid fire' created by fluids in a tight spot

Short Sharp Science: 'Liquid fire' created by fluids in a tight spot: Normally, fluids do not mix well in tight spaces because there is not enough room for disorder. But if the fluids exhibit highly contrasting viscosities, such as those of molasses and water, the researchers discovered that finger-like appendages known as viscous fingers project out of the thinner liquid (the lighter fluid pictured). As these fingers probe the thicker fluid, new appendages branch off. Collectively these tiny appendages help the two liquids mix together quickly without the aid of microfluidic devices.