The recent interchange about the lunar eclipse is a good example of how to
deal with the breadth issue. One person observed something, and asked a
question about the model...why aren't there eclipses each month? The
teacher wisely said I don't know but perhaps we can find out. An
additional tack might have been..since we know there aren't eclipses every
month, what about our model might have to be modified...that assumes of
course that the model has been constructed. Then you do what he did, you
look for new information.
I think some concerns about breadth are the result of assumptions about
the nature of science as a set of facts to be known rather than a way of
coming to know. The eclipse interchange was a good example of dealing
with the sorts of How do we know, why do we believe questions that Arnold
Arons has suggested are so important.
I believe that if an elementary teacher has a good although limited
substratum of understanding, that teacher will be able to creatively
address question raised by students...not I didn't say answer the students
questions...why would one do that, as opposed to stimulating their own
inquiry.