Dear Dad: science courses aren't just about the concrete content. They're also about learning the so-called "scientific method", doing experiments to see what happens and then discussing ways to explain the results. Studying how atoms are structured, how and why they connect, gives insights into many kinds of simple structures with complex side effects. Learning to balance chemical equations exercises math skills as well as teaching the use of explanatory logic.
Professional educators study teaching for a reason: there are many many angles to consider (true for both subject content and students individual differences). A great deal is learned in the process of teaching others, much of it can't be conveyed in words.
I can understand parents who object to mandatory education and slovenly teachers. And I despise curriculums rigged to serve some bone-headed purpose like standardized testing. But when it comes to the values served by caring professionals doing their best under trying and underpaid circumstances to maximize the benefits realized by students? Then parents need to SHUT THE FUCK UP. They wouldn't like it much if someone told them how to do the job they've invested years in either.
Most of what's wrong with education has nothing to do with the kids or the teachers. It's primarily the home environment that decides how well kids do, and the school environment that decides how well teachers do. Keep the parents and administrators out of the classrooms and leave the kids and teachers alone.