| Title | Comment | Keywords |
|---|---|---|
| Powering the Hydrologic Cycle | 03:38 - 04:37 (00:59) / 2.3 MB | "hydrologic cycle", "water cycle", weathering, erosion, "external heat engine" |
| Hydropower | 19:19 - 20:19 (01:00) / 1.5 MB | "fossil fuel", hydropower, dam, power, "wind power", "solar power", energy, "photo-voltaic cell", "external heat engine" |