Surface tension

Hydrogen bonding between water molecules at the surface results in a tough layer at the water’s surface, which is known as surface tension. Light objects such as a needle or small paper clip can be floated on water due to its surface tension. Have fun doing it with your kids. Begin by floating the paperclip on a bit of toilet paper then gently tease the tissue down from under the paperclip. The paper clip will remain floating. 

Is this an exception to a floating object displacing an equal weight of water? No. Note the slight depression of water around the paperclip. This depression is equivalent to an equal weight of water being displaced. 

A number of species, notably water spiders (spiders) and water striders (insects) have evolved adaptations to walk and feed on the water utilizing its surface tension. The following video is a fun nature film of this.