A paper clip will not 'float' on water in the same sense that a cork will. If you
position
a cork below the surface, it will rise to the surface. A paper clip will not.
If you carefully place the paper clip on the surface of calm water, however, you can keep
it
from sinking because of surface tension. In a liquid, molecules are attracted by
neighboring ones in all directions, except for those at the boundary. The unequal
attraction of neighboring molecules at the surface forms a kind of 'skin'. This surface
tension is responsible for minimizing the surface area of a free-falling drop of water
into
a sphere.
If you look closely at an object suspended by surface tension, whether it is a paper
clip,
insect, leaf, etc. you will notice a slight depression in the surface supporting the
object.
As long as the pressure exerted by an object is low enough, surface tension can support
it.
Low pressure requires a large area in contact with the water relative to weight.
Answered by: Paul Walorski, B.A. Physics, Part-time Physics Instructor
'One cannot help but be in awe when he contemplates the mysteries of eternity, of life, of the marvelous structure of reality. It is enough if one tries merely to comprehend a little of this mystery every day.'