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Re: [Phys-L] physics and potatoes


On 2015, Jan 14, , at 08:21, John Denker <jsd@av8n.com> wrote:

On 01/14/2015 07:05 AM, Folkerts, Timothy J wrote:

The solution is about SERVING potatoes, not BAKING them. If Hewitt
is answering a different question than he himself asked, then he was
DOUBLY confusing. If Anthony was mis-remembering ("I saw a question
in Hewitt about why potatoes are wrapped in foil for _BAKING_".),
then all of a sudden Hewitt seems considerably more intelligent. (I
don't have the book to check.)

Hewitt's question is:
In terms of physics, why do restaurants serve
baked potatoes wrapped in aluminum foil?

The word "serve" changes a few details ... but it does not
get Hewitt off the hook.

This is supposed to be a real-world rich-context problem.
Students are supposed to use their knowledge of the real
world in order to answer the question. This should be
obvious from the fact that the question does not specify
the thickness of the foil, the thermodynamic properties
of aluminum, or even the temperature of the potato. Cold
potatoes are perfectly edible, as in potato salad.

It is a travesty to pretend that potatoes are wrapped in
foil /after/ baking. In restaurants, wrapping potatoes
is highly atypical, and wrapping them after baking is
orders of magnitude more atypical.


If one is generous, then when the foil is wrapped is irrelevant. —it’s the serving. Since it’s not a hot potato when wrapped before and makes little difference in the cooking (except water retention).

bc does not imagine restaurants have foil wrapping machines for hot potatoes.

btw, if a patron specifies a dry potato then fork punctures will suffice while still, tho less, retaining “heat”. I suspect not much “heat” loss after baking for the forked potato due to water loss.

p.s. has anyone done the science faire and enquired of their local restauranteurs? Hewitt is a Friscan, perhaps wrapped potatoes is (are?) endemic there. I’ve eaten at many, and often there, but never order potatoes.