Under Construction by Rebecca Perry
The sol-gel transition (also known as gelation) is simply a change from a liquid state to a gel state. In the liquid state, components in the liquid move about the liquid. In the gel state, these sub-units bond together to form a network extending through the whole substance. This network gives the material an elasticity, a solid-like property.
-Pectin, (jam, jelly)
 R. Jones, "Soft Condensed Matter," Oxford University Press Inc., New York (2002).