The Story of Stuff Project's The Story of Plastic (2019) is the best systems-level film for 15–18s: it follows plastic from oil well to landfill and into the politics of waste exports. The 2021 animated short (about four minutes) is embeddable and suits 9–14s. Supporting materials include a virtual screening guide, a research guide, an action guide, a myths-and-FAQs page and a standards-aligned study guide (in-person and remote versions), plus shorts on bottled water and microfibres.
Who made and funded this: the Story of Stuff Project, a US non-profit, funded by donations and foundations. The shorts are CC BY-NC-ND (screen freely, no edits, non-commercial); the feature needs a screening licence, free for classrooms on request. How to use it: the animated short as a starter for 12–14s; the feature plus study guide as a full 15–18 unit.