Science journals are becoming increasingly common in K-12 classrooms. Teachers are using them to access student thinking, to encourage reading and writing across the curriculum, and to make assessments more authentic. Journals can also be fairly easy to adapt for different learners. Some (or all) students can journal collaboratively, for instance. Other students can use technology like iPads to create e-journals if a writing accommodation is needed.
For tips on what a science journal is and how to involve your students, check out this short article on eHow.