Slowly lower the straw into the colored water. Push the bottom end of the straw into the clay. The straw can now stand in a vertical position. Quickly turn the jar upside down over a sink. Observe the liquid level inside the straw, if any.
Colored water remains in the straw.
The height of the water in the straw is the same as that of the water before it was poured out. Water molecules are attracted to each other. At the surface of the water, the molecules tug on each other so much that a skin-like surface is produced. The air in the straw pushes up on the water when the jar is inverted and water molecules are pulling from side to side.