When I was in middle school I had a year of "Earth science," which I actually remember as one of the more interesting science classes -- I mean hey, it beat weeks and weeks of binomial taxonomy a couple of years later. Still, what I remember from the class boils down to the definitions of the following terms:
- igneous, metamorphic, sedimentary
- plate tectonics
- magma vs. lava
- core, mantle, crust
Hmm, yep, that's about it. I may be forgetting some terms, but then, I may already have known most of the above terms prior to the class, since we always had fairly nerdy dinner conversations. I definitely knew about erosion and the water cycle before taking the class, but I imagine that was also covered.
In lieu of schooly earth science, lately we've been watching episodes of How the Earth Was Made, a History Channel program (instant playable on Netflix) that actually manages to make geology interesting. I mean, geology is interesting, but given the extremely long time frames it can be tough to get people too excited about it.
I figure that watching all 24 episodes of this show is far superior to my own middle school earth science class, and it's not a criticism of the teacher or even the textbook necessarily, it's just... computer animations and video footage are so much more informative than those textbooks. And the information is up to date to within the past 1-2 years. And the same vocabulary terms are introduced, only in context, at a point in the show where you actually need to know that term. And you get to hear real scientists talking about hypotheses and data and their field experiences; science is not presented as dead facts, but rather, as an ongoing investigation.
Anyway, I highly recommend the series to homeschoolers. But note that some episodes involve natural disasters (Krakatoa killed 40,000) and a few may cause kids to worry (the San Andreas fault or the Yellowstone supervolcano). So choose the episodes accordingly.