The whole subject of teaching by any means is endlessly fascinating,
and particularly so in science museums.  Exhibit designers have
to decide what they want to convey and what they need to do engage
the audience, which inevitably has members coming with a variety of
preexisting knowledge.  The parents and the kids must be interested
and entertained and educated, and you have to evaluate whether the
designers succeeded in order to improve their art.

I've had delightful arguments about the issue with a friend who is
a very skilled museum curator.  (I much preferred the old Franklin
Institute when it was stuffed to the rafters with stuff!  The style
today is more a playroom for kids with interactive displays and
precious little stuff.)

I think such a player piano model should be completely physical;
no LEDs, etc. -- you can't see electrons.  I think the model should
have physical gauges tubed to the various parts of the action and those
gauges should be transparent, too.  The hands-on part could be arranged
with rubber bulbs of the sort used for basting or bicycle horns, as
well as finger holes to atmosphere to operate the model.

Acrylic plastic is easy to work with, machine, glue, cast to shape,
polished to clarity, etc., when you have the correct tools.  Basically,
the tool tip, cutting speed, lubrication and cooling need to be
correct.  The rest is simply time and money.

Douglas Heckrotte
Philadelphia, Pennsylvania