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## coe. conning the maths

### iandol on wed 11 sep 02

Dear Rush,
Sad that we put your brain in a spin with that elementary Algebra. I =
used to have problems with that sort of expansion until I returned to =
the old Greek methods of learning using concrete examples.
With this one it is easier to think of adding a small proportion =
uniformly to three faces of a cube to create a new cube. (It will also =
work for a rectangular prism but that adds two new terms). The bits you =
add on have volume. There are three bits which are square thin sheets, =
three bits which are long narrow square section rods, and one tiny bit =
which is a new cube. When you glue these onto your original cube you =
have a new, slightly larger cube. With the mind of a Sculptor, you will =
have no difficulty visualising this in your imagination.
I have a similar but unrelated way of solving Pythagoras theorem.
Getting back to the Cubic to Linear relationship for CoE. The precision =
of the argument "Divide the Volumetric Coefficient Expansion value by =
three" as contrasted to my "Take the Cubic Root of the value of =
Volumetric Expansion Coefficient" can be tested by displacement of water =
and the application of heat to a precisely measured specimen of some =
substance with a known CoE.
You will understand that this test cannot be applied to derived =
information which is given to potters, since they are not available in =
the required form.
My best regards to you, and Gloria.
Ivor Lewis.