2) Actually, for social studies and science, I can't say I disagree there. At lower grade levels, these topics are covered superficially at best, and I see a lot of value in going deeper rather than faster.
I agree in principle, but the thing is that elementary level science books all teach pretty much the same thing at every grade level. In much of what I've seen, the primary differences are that 1) the vocabulary words change and 2) each grade level presents more detail (hence the change in vocabulary terms). IMO, this structure argues in favor of acceleration. Grade-school science isn't structured like, for example, college-level chemistry, where you really
must understand general chemistry in order to get through O chem.
I became aware of the structure of US K-6 science six or so years ago. At the time, DS14 was doing fourth grade science in a school where fifth and sixth graders were in the same room for science. He overheard their lessons, and he wanted to skip ahead to at least the fifth grade stuff because it was more detailed, and to him, more interesting. The teacher wouldn't allow it. She honestly believed that a student wouldn't understand the fifth grade stuff without having gone through the fourth grade book. She didn't have a background in science, and I think she didn't see that the 4th-, 5th-, and 6th-grade books were all teaching the same stuff at different levels of detail.
