I would like to show how water can be pumped using a rotary pump. This is for my Grandson's (4th Grade) science project.

[We watched] a Science Channel special on how a village in a desert area of Africa is moving water from a underground source to their village. The village has set up a merry-go-round, the children playing, spinning the merry-go-round raise the water from the underground source.  The water is stored in a storage tank and the people use it as needed.  It is basically a Rotary Pump and the children supply the power. Once the children get tired, wind or solar power could be used to operate the pump.

We could use a bank of solar cells to show the Sun's energy at work. We could also hook up a venturi chamber to an electric fan, to simulate using the energy of the wind.

I am looking for a small science fair size Rotary Pump.