Earth Science has been a huge struggle for us for the 1st - 5th grade crowd. I just couldn't find curriculum that was complete enough, or interesting enough, or not too challenging, or explained things well enough....those things all seemed to compete in every book I opened. As a last ditch effort, I borrowed Geology Rocks!: 50 Hands-On Activities to Explore the Earth by Cindy Blobaum from the library.
This was a FANTASTIC find!! It had everything I needed. I will definately buy this book for the next time through Earth Science. It covers minerals, gems, rocks, crystalization, Mohs' scale, streak test, meteorites, Earth's make up, plate tectonics, volcanos, earthquates, water table, weatherization, glaciers, fossils, caves...there's a lot you could pull out of this book -- plus a few historical scientists tossed in for good measure.
In addition, I borrowed Rainbow Resource's Classroom Collection of Rocks and Minerals (Item #: 002263 Retail: $41.25 Rainbow Price: $33.75) from a friend *Thanks, Tina!* This turned out to be just what we needed. The elementary kids REALLY enjoyed their work and they learned ALOT in a REALLY short time!
In addition to the above work, I also had some weather books that I'd picked up used (weather books were super easy to come by and we found some great websites, too!)
For my middle school girl, we used Prentice Hall's Dynamic Earth, Exploring Earth's Weather, & Exploring Planet Earth. I had a lot of reservations about it and it was a compromise -- it came as close as I could find to what I wanted, but I didn't really find ANYTHING that I thought would be great for that age. It wasn't as bad as I had feared, but not as interesting as I'd hoped. She can handle material that's not as interesting, so it worked out...but I can't exactly recommend it. Just wanted to let you know about our experiences!!