科学素养与生活应用·英语30篇（4）

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为何某些昆虫能在水面行走而另一些则立刻下沉

Water striders stay afloat thanks to surface tension—a cohesive force creating a 'skin' on liquid surfaces.
Their lightweight bodies and hydrophobic leg hairs trap air and distribute weight over large contact area.
Each leg depresses the surface slightly but never breaks it, like tiny dimples holding them up.
Denser insects like ants lack sufficient leg-to-mass ratio and break surface tension instantly.
Soap or oil contamination reduces surface tension dramatically, causing all insects to sink immediately.
Engineers mimic this principle in micro-robotics for aquatic surveillance devices.
Surface tension also enables capillary action that draws water up plant xylem against gravity.
Temperature affects tension strength—warmer water has weaker surface cohesion.
Even slight vibrations from wind or raindrops can destabilize delicate water-walking balance.
This phenomenon illustrates how intermolecular forces shape everyday biological and physical interactions.