This teacher's guide attempts to answer questions such as: What causes ocean currents? What impact do they have on Earth's environment? and How have they influenced human history? Seven innovative activities are provided in which students can gain fascinating insights into the earth as the ocean planet. Activities focus on how wind, temperature, salinity, and density set water into motion. An "in-depth" investigation of the key physical science concept of density in which students model how pollution dumped in one location can spread throughout the ocean is also included. Learning is placed in a real-world context as students predict and analyze routes taken by shipwrecked sailors, the 1990 Nike shoe spill, the raft Kon Tiki, and other voyages. In the seventh activity, "Message in a Bottle," students create stories to show what they have learned over the course of the unit. (ASK)