Water droplets that travel uphill

These water droplets are travelling uphill.

The track is heated and covered with tiny asymmetric ridges. Together, heat and texture propel the drops.

Real droplets moving uphill on a heated ratchet track — Science Friday / University of Bath researchers. Documentary excerpt; original playback speed retained.

On metal hot enough, a water droplet rides on a cushion of its own vapour.

This is the Leidenfrost effect—the same reason droplets can skate across a very hot pan.

How a water droplet rides on a vapour cushion above heated ridges — Pandi explanatory diagram based on the cited research. Schematic, not to scale.

Add a carefully shaped surface and the vapour flow can drive droplets along a chosen route.

Bath researchers used this principle to build tracks and a maze for water.

Slow-motion footage of a droplet travelling over asymmetric heated ridges — Science Friday / University of Bath researchers. Documentary excerpt; original playback speed retained.

These water droplets are travelling uphill.

The track is heated and covered with tiny asymmetric ridges. Together, heat and texture propel the drops.
On metal hot enough, a water droplet rides on a cushion of its own vapour.

This is the Leidenfrost effect—the same reason droplets can skate across a very hot pan.
Add a carefully shaped surface and the vapour flow can drive droplets along a chosen route.

Bath researchers used this principle to build tracks and a maze for water.

Water droplets that travel uphill

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