The beauty of these foldables is that there is no pasting or stapling of papers into the journals. You simply use the pages that are already in the journal. The following example really requires only 1 page from the notebook, but I used the page behind to pose a question "What happens in..."

The purple lines indicate a cut. The blue paper is inserted to help differentiate between different pages. 

When you flip each tab, there's a written explanation and a diagram. 

Here's a foldable for density that uses 2 consecutive pages. Density is written in graffiti style letters on the back page. The front page is folded over in half and there's a cut down the middle. You can easily have students write down examples of things that float or sink under the appropriate flaps. 

When you completely flip over the first page, under the graffiti letters is a definition of density and diagrams that represent different densities. Note that the least dense is still on the left and the most dense is on the right. 

This book is good for organizing information occurring in 4. You can make the tabs all the same size, or you can customize the flaps to fit the information. Just simply fold the paper hot dog style and cut the top flap into as many tabs as you need. 

This book is also good for showing a short sequence. Ex: Life cycles. 

Students can also use this to collect data for an experiment that may last several days. One one flap they draw what they see, on the flap underneath, write their observations. 

This can easily be made into a 4 tab foldable. This is great for vocabulary. Students are able to represent the information in different ways. 

In one box, have the students write the vocab word.
The one box, have the students draw a representation of the word.
In one box, have the students write the "official definition"
In one box, have the students write the definition in their own words.

If you want, you can even have students write the definition in another language, or draw non-examples. 

You can teach the students to create this foldable, or just print out templates for them to cut out. You can download a template that I created below.