Mini Vortex

This was a result of my first experiments to create an air-core vortex in a transparent cylinder. As the water rises in the acrylic vessel the vortex is created and reaches the top. For a while the water flows over the edge and falls on the outer surface, to return to the reservoir below through a narrow slot around the base of the cylinder. Then the pump stops and the level falls, still maintaining the vortex until it reaches the bottom, and the cycle starts again.