Published online by Cambridge University Press: 15 February 2011
More than 100 years ago Worthington [1,2] reported his observations on drops exploding on impacting rigid surfaces they did not wet. Mercury was his favorite fluid, since mercury does not wet most solids. For water drops he had to especially “smoke” his surfaces to make them non-wetting. In his day high speed photography had not been developed, but he had learned to “stop” his falling drops by spark illumination. His drops had radii of typically 1 mm, fell from a height of ∼10 cm and ejected always an even number of spikes, typically ∼24. These spikes would shoot out from the impacted area at velocities several times higher than the impact velocity.