If you remember from WTM, the study of the human body and the animal kingdom is an encyclopedia-based study, and the plant kingdom is mainly hands-on plant growing. Some parents find that a little overwhelming, since there isn't a laid-out plan for each day's lesson... but I like it. I let my kids choose a body system or animal (depending on what we're studying) and then we go with it.
(Here's an example of a perfect science lesson from last year.)
If you're intimidated by so little guidance, look here for a homeschool mom's lesson plans for every WTM year of science. Also a link in the left sidebar.
Remember to gently direct your kids to not do all cute and cuddly animals, or not all fierce and scaly ones, as their gender or preference may dictate. You definitely want them to explore what they love, but stretch them a little to also check out how strange a slug, blowfish, toucan, or swordfish can be.
I created a form for my kids to fill out that uses the "big science words" like hibernate, omnivore, endangered, and camouflaged. When we fill it out together- circling choices or filling in the blanks, we can talk again about what the words mean. The entire right side of the page is blank so he can jot down more info. Sure, he could just circle "lays eggs" but why not write "1-3 eggs" or "up to 50 eggs" in the side too? This is true for most of the answers.
This form will also work for any type of resource too. It is open-ended so that pretty much any encyclopedia or reference work will have this information. I really like it.
Check out the Magic School Bus books
When we're having a rough day but I want to stay on track, we climb in my bed with a short book that usually tours the human body in less than 30 pages. The kids can do most of the experiments with things we have on hand. The Human Body: A First Discovery Book
I really, really like the e.Encyclopedia Animal (DK)
The "Life of Plants series
If you are enjoying Elemental Science's WTM-based lesson plans for the Grammar stage, here is her book list. Many of the books are duplicated from above. (it is, after all, WTM-based!)
I'm so pleased you are utilizing Classical Curriculum!
Teresa (Tracy) Dear