Earth is a complex, evolving body characterized by ceaseless change. To understand Earth on a global scale means using a scientific approach to consider how Earth's component parts and their interactions have evolved, how they function, and how they may be expected to further evolve over time. This video points out the complex interactions between Earth's atmosphere, oceans, and land, and helps explain why understanding Earth as an integrated system of components and processes is essential to science education. The segment is five minutes thirty-one seconds in length. A background essay and discussion questions are included. Educational levels: Middle school, High school