We started out with water and spent sometime exploring the qualities of water: volume, capacity, surface tension, permanence, gravity, displacement.
Later I introduced some fresh herbs picked from the garden to add an additional layer of scent to the water work. The lavender was the biggest hit and I added a few rocks as a provocation for a make-shift mortar and pestle.
The next week, color was introduced. I filled baby food jars with primary colors: liquid watercolor and water. Instantly some children were very interested in using the pipettes to carefully draw out a bit of color and create intricate color palates in the dishes available, while others were still mostly interested in exploring volume and capacity by dumping the entire color into a small dish.
As this area develops, more things will become available. Having a special area, with a special name, gives the children another avenue to explore their social inter workings as their games spill forward into the entire yard. It gives them an opportunity to practice their refinement in communication skills while exploring the qualities of the work available. They decide the rules on a daily basis and often are constantly refining and enhancing what works and doesn't work that day. These problem solving skills on various levels are is our life long work, though really we look at it just as play.