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of cars ...

Literally referring to motion across the surface of water, hydroplaning is a phenomenon often observed in cars driving quickly on wet roads just after it has started raining. At some critical balance between the weight of the car and its speed, the car tire loses molecular contact with the road and a thin film of water separates the two. Now the car is skimming on a (virtually) frictionless surface, making steering ineffective. One can quickly lose control of the vehicle.

of water on itself ...

Another interesting phenomenon of water, related to the physics that causes hydroplaning is the ability for beads of water to skim across a surface of a larger body of water without getting sucked in. If you've ever run a faucet into a full sink or a big pan of water, you may notice short-lived balls of water skittering across the surface away from the falling water. They exist long enough that you can be sure they're not bubbles. They move very fast and then vanish. In a way, these beads of water are hydroplaning as well. A thin cushion of air (optically determined to be on the order of nanometers) separates the bead from the water. This cushion is maintained as long as the water is moving quickly - similar to a piece of paper moving quickly and practically frictionlessly across a desk. Experiments have been done to test this hypothesis where the surface of water is pumped with a low amplitude vibration. This vibration maintains the separation between the surface and the bead, and drops of water have been maintained on the order of minutes.

Because water has such a high surface tension, it tends to minimize its surface area. Thus, small volumes of water will form spheres. The interaction for this surface to be disrupted require molecular contact between water on the bead surface and on the bulk surface. An alternate theory to the air-cushion hypothesis is that electrostatic repulsion maintains the separation while the bead is moving quickly. As it slows down, water can then reorient and allow cross body interactions, thereby assimiliting the bead into the bulk water.