This summer (2010), I played with a Hui machine at my parents house. It is fascinating.
The very simple device is also known as the
gee-haw whammy diddle,the mystery stick, hooey stick, the idiot stick,
the magic windmill, the notched stick, the truth stick, or the stick-propeller device.
Its physics is interesting. Rubbing a round wooden stick together produces a vibration whose elliptical excitation is transformed
into rotational motion of a propeller. All the material as well as the rubbing appears to be symmetrical. Nevertheless, the
user can change the direction of the wheel. Still today, the best explanations are from the 1980'ies.
There are still many questions to be answered about the device. It is a pedagogical tool to illustrate what an
experiment is, to see the process of hypothesis building and then to build an explanation.
When does one really understand it? |
I add this to the pedagogy pages because concrete experiments and explanations illustrate a lot about what science is.
Simple tools, which can be played by kids (and adults) are especially attractive
As a first year mathematics student at the ETH, I had a nice general physics exposure.
The lectures would always feature experiments. At one point,
the Tippe top came up.
(see Pauli and Bohr playing with such a top. Source: Nahin's book
Mrs Perkins's Electric Quilt).
Our physics professor Hans Joerg Leisi mentioned that the details of the mechanics of this device is not
completely known which made me curious about it. Candel Water experiments
are other examples for entertainment.