The Lorenz Water Wheel

Planeten Paultje

At the Dutch Physics Teachers Conference, the "Woudschotenconferentie Natuurkunde 2005",

the Orion Astronomy Club presented a booth centered on the conference theme:

"Physics and a Habitable Earth".

Part of the booth was a "Lorenz Water Wheel", intended to introduce the concept of

"Deterministic Chaos",

which is a major factor in many processes on our Earth, but which has no place in the sub-university curricula at this time.


Without the special cooperation of the following firms, this project would not

have been completed in time:

Fixet C.Marinus, Zijlweg 35, Haarlem; De Rijwieltrust, Zijlstraat 64, Haarlem;

Hairshop Nico Weijers, Pieter Kiesstraat 78a, Haarlem; Vos Instrumenten, Zaltbommel.


The first picture shows an overview of the experiment:

Water is being pumped up from the white reservoir to the yellow bucket on the table.

A spill-over (the black hose) takes care of maintaining a constant column of water so the pressure at the stopcock is kept level.

Water flows into the topmost bucket on the wheel, which causes it to become unstable and start turning. The water flows out of the buckets through small holes.

The rotation of the wheel is transferred to a DC-dynamo via a chain belt (silicon hose with a core of ball-chain). The resulting voltage is being displayed in the Voltage-Time diagram on the computer screen. In this particular experiment a positive voltage corresponds with rotation to the right, and a negative voltage corresponds with rotation to the left.


This movie shows the experiment in action:

This is the Voltage-Time diagram that was recorded in the movie. Round about t=310 the wheel stopped, only to start turning on its own again at t=345. There may still be some unintended friction in the system.


Here the experiment can be seen from the side:


The Lorenz Butterfly in action. This animation was made with the OSX program Gerry's Attraction:


The above materials on the Lorenz Water Wheel can be found in this directory.

They may be copied and linked to freely for educational purposes.


Links to other web pages about Edward Lorenz, the Chaos Theory, the Water Wheel and Fractals:

The Royal Dutch Meteorological Institute KNMI: Edward Lorenz is awarded the 12th golden Buys Ballot medal for his work in 2004. The press bulletin and a general background article (in Dutch).

A general article by Roelof Oosterhuis on the Chaos theory (in Dutch).

The Lorenz Attractor page from the Fractal website of the Royal University of Leuven, Belgium.

The index contains a broad overview of all things fractal (in Dutch).

The Virtual Water Wheel Laboratory of Fritz Grassmann in Switserland.

This site contains an exellent applet, which can also be downloaded.

The Lorenz Attractor page of Paul Bourke.

Chaos and Fractals by Larry Bradley of Johns Hopkins University.

A search on the internet can reveal lots of interesting things.