Final answer:
Water striders utilize surface tension to walk on water, as the cohesive forces among water molecules create a 'film' that supports them due to their relatively small downward force.
Step-by-step explanation:
When water striders, also known as water skaters or pond skaters, are observed gliding across the surface of a still body of water, they are taking advantage of a phenomenon called surface tension. Surface tension is the result of the cohesive forces between water molecules, which creates a sort of 'film' on the surface of the water. Because the downward force exerted by the insects is less than these cohesive forces among the water molecules, the striders do not break this surface layer and are able to move about as if they are walking on water.