I stuggled with doing this as well, but in my science methods class we recently created two seperate lessons for science and social studies from one book! I agree with the comment below by Sierra - you can't force it! Our professor suggested that we don't have to have lesson that encompasses the book, it's story or even it's subject. If you've read a book to your class before pick a picture or situation to explain a science concept.
Here's what I did with the book "Stellaluna" by Janell Cannon for a second grade class. This one might be obvious, but for my science lesson I did "Physical Characteristics and Behaviors of Animals" and I reffered to the book to compare and contrast birds and bats. I extended the lesson - without the book - to talk about animals familiar to the children and we researched those. In the end students created their own animal with explanations of their physical characteristics and behaviors and how those things help the animal survive.
For my social studies lesson I connected how the bats in the book live in trees and how bats in Austin, TX live under many bridges. The concept was "Human Impact on the Environment". I only reffered to the pictures in the book.
So look at the books you're using during your ELA and readaloud time - see if you can pick out a tiny moment to explain a science concept.
Hope that helps!