Model-based inquiry (MBI) is an instructional framework designed around the construction, revision, and testing of models by students to make sense of and explain a phenomenon (Windschitl et al. 2008). Focusing on explaining natural phenomena provides a specific context for students to learn and apply scientific understandings to and can help engage students in scientific practices (Passmore et al. 2013). The Earth's systems MBI unit is connected with the "Next Generation Science Standards" (NGSS Lead States 2013) and incorporates elements of ambitious science teaching. This article provides an example model-based inquiry unit in which students collaborate to construct, revise, and test models as they seek to explain a natural phenomenon, Arctic amplification, a phenomenon where the Artic is warming twice as fast as the global average.