This post is inspired by recent tutoring sessions with two high school students. One student is taking a conceptual physics class, and the other is taking a physics class designed to prepare a student for the SAT II physics test. Both students go to excellent schools in a wealthy community. Both are also pretty intelligent. Why do they need tutoring?
They both have absolutely HORRIBLE textbooks. As I was trying to teach torque to my student last night, I got completely confused by the explanation in her book. It was completely incoherent. The diagrams of the example problems were even worse. I finally just closed her book and explained torque to her in the simple and straightfoward manner in which it should be taught.
But the most annoying things about these books is that they just make up laws as they go. Of course they have important laws, like conservation of momentum and energy. However, these stupid books will just make up a law for anything else. Later in the energy chapter, they came up a new law to explain why machines can put out more energy than they take in. They used a simple derivation from conservation of energy, but then they called it "The Law of Machine Energy Output" or some bullshit like that. There are many other stupid made up laws in that book. I honestly don't know how anyone can learn science with these crappy textbooks.