Final answer:
Paper clips and small insects like pond skaters are able to remain on the water surface due to surface tension, which is the cohesive force among water molecules that resists external pressure and keeps them from sinking.
Step-by-step explanation:
Paper clips can sit on a water surface, and small insects like pond skaters can walk on water due to a phenomenon called surface tension. This occurs because the molecules at the surface of water are attracted to each other, creating a 'skin' that can resist external force. The force exerted by the downward weight of the paper clips or the insects is less than the forces among the water molecules, allowing these objects to stay on top of the water without breaking the surface.
Insects such as pond skaters use this to their advantage by distributing their weight over a larger surface area with their long legs, thus reducing the force on any single point of the water surface. This allows them to move across the water without sinking. Similar effects can be observed with the delicate placement of other small objects like sewing needles or razor blades.