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Surface tension

Pond skaters and whirligig beetles use surface tension in different ways.

The surface of water forms a springy platform that supports many creatures. Water molecules are bound to one another by a force akin to magnetism but they're not attracted by air molecules above so those on the surface have their forces concentrated sideways giving the surface a specially strong tension. The pond skater hunts on it and must keep meticulously clean. The waxy surface of its body and the hairs on its feet repel water but any dirt on them that absorbed water would break the surface tension. They're aggressive insects each with its own territory among the lily pads. Intruders are immediately chased away and fights between rivals are common. The surface tension film is not only the pond skater's platform, but its sounding board. Through sense organs on its feet, it can detect the vibrations caused by the struggles of an insect that has fallen on the surface. By bouncing up and down it communicates to other pond skaters, sending keep out messages to rivals and come hither messages to potential mates. Whirligig beetles use ripples to detect prey and obstacles. Their eyes are partitioned so the lower ones see what's happening below the surface.

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2 minutes

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