Sorry to hear he had this experience. Most elementary teachers, in particular, have very little grounding in science, and often are a little afraid of math and science, actually. On a related topic: back before we started homeschooling, I used to routinely find errors in answers provided by the text used at school. Initially, I would send in little corrections, but eventually, I realized that this was just confusing and upsetting the teachers, and it was probably going to be more useful to explain to the children that teachers are only human, and textbooks are the products of people who are only human, so there will be errors and misconceptions. Our job is to learn to be critical consumers of information (but in a respectful way).
It may feel a little like creating disillusioned little cynics (though I don't think it is), but there is something to be said for teaching children that even a well-intentioned person with many admirable traits can inadvertently promulgate injustice. (This is as true of ourselves as of others.)
