<p>The reason most kids cannot take high school physics in 9th grade is that high school physics requires at a minimum, concurrent enrollment in algebra2, and it’s really best to have completed algebra2. Since many school systems don’t offer geometry to 8th graders, their 9th graders aren’t even minimally prepared to take physics. But I don’t see what the hurry is to take physics. I think it will be better understood the more math the kids have, and the usual sequence of earth science, biology, chemistry, physics, is the best approach. </p>
<p>Also, accelerating the math instruction isn’t really feasible. Our middle school does offer geometry (and algebra1 in 7th grade), to “honor” students. It’s great for the students who can handle it, but quite a few of the students in this track later struggle in high school. The real problem is that by the end of elementary school, there is a huge spread of algebra-readiness, by about 4 years in a reasonably good public school. The schools aren’t well-equipped to deal with these disparities. They don’t have enough really advanced kids to offer them their own class. Acceleration to a higher grade presents its own problems. Those kids often end up bored and not learning nearly what they could be (and they are the ones who are most likely to need those math skills later on in life). Meanwhile, you have unhappy parents whose kids weren’t selected for the highest grouping pushing to get their kids in. Consequently, you have “honors” students who could barely get a B or C even when coddled with generous middle school “extra credit” and “exam retake” opportunities arriving in high school and floundering.</p>