Everyone lives downstream
Water flows downhill, from higher ground to lower ground. The place the water comes from is upstream, and the places it flows towards are downstream. Anything that goes into the water upstream, such as litter, soap or oil, is carried along and can reach everyone downstream. In Egypt the Nile flows north, so towns, farms and animals downstream receive the water that passed upstream. That is why we say we all live downstream. This unit asks three big questions. How do the spheres of the Earth interact? How much water is there on Earth? How can we protect Earth’s resources? In the unit project you will build a model of a watershed to see how pollution in one place can travel to others. Good scientists begin with questions: Who lives downstream? How far can pollution spread? What happens to the animals and plants?
| Big question | A smaller question |
|---|---|
| How do Earth’s spheres interact? | How does rain change the land? |
| How much water is there? | How much of it is fresh? |
| How do we protect our resources? | How can a school save water? |
| Downstream | What could happen |
|---|---|
| fish | less clean water to live in |
| farmers | dirty water for the fields |
| families | the treatment plant must clean the water more |
Downhill stream model (a grown-up helps, outdoors, not near canals). Tilt a tray, build a small hill of damp sand at the high end and pour a little water on top. Watch which way the water flows. Drop a few bits of paper at the top and see where they go. Then write three questions about what would happen to places at the bottom. Clean up afterwards.