This is an awesome writing unit that incorporates science. You could actually do this unit during your science time since you are working on experiments in forces and motion. This is an excellent unit for any grade level that wants to teach students how to write lab reports and science books with details and elaboration. This is based off of the work by Lucy Calkins. You could easily change the forces and motion theme to one of your current science standards themes. I was impressed by the use of experiments to drive the work of the students.