What are anchoring phenomena (anchors)?
An anchor is essentially a puzzling thing — could be an event, could be a process — that requires the coordination of a bunch of different science ideas to fully explain. It is not something you can easily Google an explanation for. It is something that students work toward understanding throughout the entire unit. For that reason, it could also be the basis for your end-of-unit three-dimensional assessment. (Doesn’t have to be! But that’s an option.)
Why should we use anchors?
Teachers and classrooms that use anchors tend to teach for conceptual understanding — meaning that students are not just spitting back isolated facts without truly understanding “how it works”, but rather have developed a full, accurate understanding of the concept at hand. Students who have a conceptual understanding of phenomena are not only more likely to retain that information, but can also use that information to make predictions, draw conclusions, and understand new but similar ideas.
Using anchors naturally encourages teachers and students to focus on big-picture understanding, the connections between ideas, less breadth but greater depth, and a rationale for all learning. And because anchors are designed to drive instruction based on student thinking, teachers that use them tend to be more responsive to students’ developing understandings and interests. They naturally differentiate to a greater extent.
On the flip side, teachers who do not use anchors (those puzzling big ideas or events) to frame their instruction tend to focus more on the factual information without making connections, have more difficulty providing a rationale for learning and tend to overload students with more ideas than they can process in a class period. These teachers also tend to simply plow through the curriculum without making the necessary adaptations to truly guide their students from where they are to where they need to be.