One thing I learned from our current and past experience with Montessori work is that kids tend to be more willing to write and creative with their work when they can choose the topic. All school year, about twice per week, I'll give Nathaniel a piece of paper that is blank on top and lined on the bottom and have him draw a picture and write about it. Lately, we've been studying space, so the examples you'll see are from his space binder, I've been asking him to draw a picture about space and write about it. He has been doing all of this writing of facts from pure memory.
I love the V20 at the top, he thinks he's cool for coming up with it for "venus second planet zero moons".
We keep all the papers together in a binder with clear page covers in case anyone wants to read them or look at them.
Another thing we do is put together mini books about a topic. Here, I have stapled together about 12 small rectangles of black paper with a white cover. He has written "My constellation book" on the cover. Each day, he chooses a few constellations to draw and label. I am trying to get him to realize that the dots are more important than the lines because the dots are what you will only see in the sky. We are using cray-pas to draw on the black paper. He enjoys looking through all the books, trying to choose which constellation to put in his book.