Approaches To Bundling
The NGSS has identified two approaches to bundling the standards — a topic model and a phenomenon model. The topic model is designed to group standards by topic. For schools and districts that are looking to quickly implement some degree of NGSS instruction without entirely overhauling the curriculum, this approach may be the better option — for now. This model also works well for disciplinary-based courses — versus those that operate on an integrated curriculum. For teachers brand new to the NGSS with little experience working with standards, this approach may be easier. It would allow you to build upon the curriculum you are currently working with.
That said, the phenomena model is the recommended model. In the phenomenon model, standards are bundled in an instructional unit designed to explain a particular phenomenon. For example, students may observe that glaciers (large sheets/rivers of ice) often have dark bands. What explains this? A phenomenon like this could tie together several Earth and Space Science standards with MS-PS3-1 that addresses the relationship of kinetic energy to the mass of an object. As students learn about the cycling of Earth’s materials and flow of energy, changes in Earth’s surface over its long history, and the cycling of water, they would apply these understandings to the glacier phenomenon to develop a more complete understanding of the interrelatedness of these concepts.
While the phenomenon model is the best aligned to the intent of the NGSS, it may require greater changes to the curriculum at both the course level and across grades. However, if you are working with an integrated set of PEs and have already been tasked with developing a new course outline, this approach may not be any more difficult to implement than the topics model.