Researchers studying condensation have noticed something strange: When a surface is covered in oil, condensed water droplets randomly fly across the surface at high velocities, merging with larger droplets, in patterns not caused by gravity. The culprit is unbalanced capillary forces acting on them.

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Researchers studying condensation have noticed something strange: When a surface is covered in oil, condensed water droplets randomly fly across the surface at high velocities, merging with larger droplets, in patterns not caused by gravity. The culprit is unbalanced capillary forces acting on them.