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Vn68.1 Continuous Quantity 8/18/77

As is the case with many who have a few fine things, we hardly
ever use them. Our silver and china are in some dark corner, our
Venetian glassware sits empty, hardly touched. At dinner our common
wine goes into common wine glasses. Through accidents at table and
sink, the usable collection has become one made of odds and ends.

This evening a guest joined us at a picnic supper on the patio
behind the house. Unloading supplies from the basket, I found (beside
the dinner meats) one jug of wine and three glasses of roughly these
shapes:

the figures are on Addendum 68-1, original text of the vignette.

I placed the empty glasses on the picnic table in the order shown and
posed a problem abstractly to the children: “How can I be sure nobody
gets gypped when I pour the wine?” No response was forthcoming.

As I poured wine into the first glass, Robby cried out: “I got it.
Pour the same amount at both ends. Empty one into the center glass,
then refill the one you just emptied.” It was clear he meant refilling
the glass would result in its matching the first. Miriam concurred in
this solution.

Because the middle glass had a non-standard shape, as I followed
Robby’s procedure I arrived at a wine distribution whose appearance was
deceptive. There appeared to be a greater volume in the center glass
because its top circumference was greater than that of the two matching
glasses and its height was greater than both (since its cross-section
was more nearly conical than cylindrical).

the figures are on Addendum 68-1, original text of the vignette.

When finished pouring, I exclaimed, “You’re wrong, Rob. Look. The
center one’s got more in it. I’ll take that one.” (My overacting was
supported by a few gleeful chortles). When I then disbursed the
matched glasses to Gretchen and our guest, Miriam censured me: “Daddy,
you’re just being silly.”

Relevance
Consider this anecdote as an informal post-test of Miriam’s
conservation of quantity. I do. I intend to introduce such ‘experiments’
into our everyday life as this project draws to a close. My purpose
is to reduce the testing burden Miriam will face by performing informally
those post-tests whose conclusions should be beyond question, without
rendering the evaluation sequence subject to the criticism of
incompleteness.

Addendum 68-1

Vn 68-1 Original Fair Text of Vignette 68

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