The authors of NGSS suggests starting each unit with a phenomenon—a real-life example that engages students and encourages them to ask questions. They encourage phenomena that matter to students and connect to their lives.
While this unit is not framed around specific phenomena, it is designed to be used flexibly. The lessons can be used individually or together, and they can support student learning around any number of phenomena.
Below are are some ideas to get you thinking about phenomena for framing these lessons in your classroom.