Re: Impact of Spheroidicity

[Leigh Palmer <palmer@SFU.CA>]

> All this forth and back about weight and how it differs at various points on
> Earth's surface reminds me of a factoid from my colleague Tom Skinner:
> "Strange as
> it may seem, the Mississippi River flows uphill."

meaning, I think, that the mouth of the river is farther from Earth's
center than is some point far upstream. One could also say that the
river's flow is impelled by centrifugal force. Such statements are ones
we physicists can all understand and enjoy, but until a student develops
the ability to see as we do, such a statement looms larger in importance
than it should. The student may even reject physics as being -
unphysical!

I don't think the Mississippi flows uphill if one adopts my definition
of "down" as the local direction of the force associated with "weight".
I claim that is a point in the definition's favor. While we all love
counterintuitive factoids, we get along without this one in an
introductory physics course. Surely having a more reasonable definition
of "uphill" is pedagogically superior.

Leigh