Ron Smith closes out Yale's Atmosphere, the Ocean and Environmental Change course with a synthesis lecture pulling together the semester's core ideas. He revisits the physical properties of air and water, then works through hydrostatic and geostrophic balance as they apply across the atmosphere, ocean, and solid earth. Several equilibrium states and static stability are reviewed before he turns to how heat and mass move through the earth system via winds, ocean currents, and rivers. A section on mixing, dilution, and concentration connects to pollutants and ocean salinity, and the lecture ends by examining the asymmetry between the northern and southern hemispheres, tracing it to differences in land mass distribution, Coriolis force, and seasonal patterns. Recorded in Fall 2011 as part of Open Yale Courses, this is a compact recap lecture useful as either a course capstone or a standalone survey of physical earth-system dynamics.