I don't think this problem is confined to science, or to middle
school. A book by James W. Loewen called Lies My Teacher Told Me
discusses problems with high school history books. Evolution is
missing or downplayed in many biology textbooks, and in Alabama,
biology books have to carry a disclaimer saying that
evolution is "just a theory," and can't be proved because
"nobody was there to see it happen." I wrote a fascinating ;-)
article on why textbooks are so bad: http://www.lightandmatter.com/article/article.html
In 25 words or less, I think it has to do with perverse
economic incentives.
IMHO, the vicious cycle of bad K-12 science education can't be
broken simply by creating new curricula for preservice teachers,
or working with your school board (although those things couldn't
hurt). I think the U.S. needs to:
1. Increase K-12 teachers' pay by about 50%.
2. Stop expecting K-6 teachers to be generalists. Have
different teachers for humanities and math/science.
This would instantly change the supply-to-demand
ratio of qualified teachers by a factor of 2.
The best texts in the world won't help until measures like
these are taken to get competent teachers in the classroom.
Conversely, competent teachers wouldn't put up with substandard
texts.