George, I thank you for your candid reply. I share my reflections online like this precisely so that I can engage with and learn from others'. It sounds like our teaching experiences have been different: I have generally had a huge amount of autonomy and respect in developing my physics curricula; I have not been forced to engage students in activities that I don't believe in. (And I completely agree that many projects invented in the name of engineering don't actually empower students to discover fundamental truths about the universe, marble runs being a canonical example.) I'm saddened to hear from you that there are places where fads get pushed onto good physics teachers who would give their students more meaningful experiences if only the teachers' expertise were respected. I wouldn't want to remain a physics teacher in an environment like that.

Regarding physics first, I'm actually a huge fan. I do enjoy 9th graders' personalities, which I know not every physics teacher does. But I also believe 9th graders can uncover fundamental laws of the universe through multiple representations even when - for example - we restrict ourselves to using only whole numbers because the students don't yet understand fractions and decimals. I don't see upper level math as a prerequisite for students to make meaning of slopes and areas of graphs. The equations 9th graders can solve are simpler than the equations 11th graders can solve, but the truths they uncover can be just as profound. (If you're interested, I wrote more about physics first here: https://medium.com/educate-pub/why-dont-more-high-schools-teach-physics-first-1ed8d228ed92)