How can we stop plastic waste from entering and traveling through the world’s waterways? How does plastic go from me to the sea? Students engage with the “Sea to Source: Ganges” river expedition, and the journey that this team is making to track plastic from its human consumers to the world’s waterways. Generating ideas from the data-collection approaches in this mission, students brainstorm and refine methods they will use to understand the movement of plastic within their own watershed.