Brinicles

Description:  As ocean water freezes into solid ice the remaining saltwater forms into icy "stalactites" that descend into the ocean. This can be used as a phenomenon in an elementary class to show changes in state. In middle and high school the chemistry can be explored more deeply.

Web Resource:  Brinicle - Wikipedia

Brine icicles form with sinking supercooled water. Video by Umi, diver in the video is Steve Rupp.