Final answer:
Water striders are able to glide on water due to surface tension, which is caused by cohesive forces between water molecules. Their wide legs distribute their weight to avoid breaking the surface tension, and tiny hairs on their legs increase buoyancy.
Step-by-step explanation:
Understanding How Water Striders Stay Afloat
The phenomenon of water striders being able to move across the surface of water can be attributed to the concept of surface tension. Surface tension arises due to the cohesive forces between water molecules, which are the result of hydrogen bonding. Water molecules have a stronger attraction to each other at the surface, creating a 'skin' that resists external force.
As described by the model of a liquid surface acting like a stretched elastic sheet, water striders leverage this tension to their advantage. They have specially adapted legs that distribute their weight over a larger area, minimizing the force on any single point. This wide distribution prevents their legs from breaking through the water's surface.
Moreover, the water strider's legs are covered in tiny hairs that repel water, increasing buoyancy. Thanks to these adaptations, the downward force exerted by the water strider is less than the surface tension of the water, preventing the insect from sinking. Thus, water striders can effortlessly glide across the water, making use of cohesion and surface tension, to stay afloat.