I’ve used the astronomy with my 2nd grader and am now using the botany with him as a 4th grader. We both really like (love) this series.
It keeps our attention by keeping it interesting, using great photos, and ties it all in with everyday examples. The author gives the right amount of info and then asks relevant questions to help retain the information. The experiments and activities and very helpful and instructional, no busy work at all.
I also use the journals and lap books (Journey Through Learning).