I would like to question the instructional qualities of analemmatic
sundials.
Unlike Tony Moss' 'Multi-dial', it is my view that there is only one
relationship easily illustrated - the projection of a polar dial on to a
horizontal surface is an ellipse with corresponding hour points. It is
extremely difficult why (or how) a vertical person or staff casts a
shadow to these points.
I am afraid that the instruction falls into rote learning of procedure
like so many sundial kits (and much of pedagogy). I do not know what
the underlying motivation was for "that part of the UK National
Curriculum". I assume it was to understand something of the natural
world and not to acquire the skill of making a sundial. Under that
assumption I think the analemmatic falls short and could produce
confusion for inquiring minds.
With that said I certainly would NOT join any ban on such dials as
"dangerous for children"! Indeed, both children and adults interact
with them quite well and they can make a beautiful asset in a school.
However, expect difficulty with a persistent inquiring person seeking
explanations.
Perhaps someone on this list can show me a way to explain that to anyone
lacking much geometric skill such as a 10 year old (or me).
Claude Hartman
(retired science teacher basking in the sunshine of 35 N, 120 W)
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