Water is a key ingredient in all life. Water has many unique properties due, in great part, to its hydrogen bonding. Water sticks to itself. It forms droplets. It acts like it has a film on top.
Water can absorb a lot of heat without changing temperature very much.
The Corningware pot can absorb more of the heat from the burner without changing temperature as much. In the summer, in the daytime, lakes and oceans can absorb a lot of heat from the sun, keeping the surrounding air much cooler. That's why costal areas tend to have more mild seasonal changes. If ice sank, in winter as water froze, it would sink to the bottom of ponds and lakes, thus they would freeze from the bottom up. Thus, it would be impossible for any organisms to live in water.