This often results in public school teachers being less willing to answer advanced questions, which are beyond the prescribed curriculum.
This is what I do not understand - if the lesson plans do not include a particular topic (let us say, a 2nd grader wanting to know a single extra detail about tectonic plate movements which is out of the teacher's scope and knowledge - after the teacher talks about tectonic plates in the class), what effect does answering this question have on the "achievement gap" between students in a public school classroom? If the teacher took 2 minutes to answer that question, the whole class would have learned something new and the topic is guaranteed to never appear in a 2nd grade standardized test and hence has zero effect on capping the growth of top students or widening any gaps in knowledge between students. So, why shut a genuine question down? The student obviously thought a lot about a concept and wishes to understand some thing.
