We are using Anna Botsford Comstock's Handbook of Nature Study this summer.

It is filled with six years worth of nature study!

I love this book!

It can be used as an indepth study or as a quick learning experience.

I just pay attention to what the kids are observe, or what happens to pop up in our daily lives.  Out comes the book!  I look over what I would like them to learn.  It only takes a few minutes.  Best of all, the kids are already interested in the subject at hand, so the information is really processed into their minds!