Wind, water and weather: what do we know?
Now let us gather what we know. Weathering, erosion and deposition work together as a chain. Rock weathers into pieces, the pieces erode, and then they are deposited as sediment. Scientists decide which process they see by looking for clues. A cracked rock with crumbs at its foot points to weathering. A muddy stream and a bare slope with channels point to erosion, because material is on the move. A pile of sand at the bottom of a hill or a river bank of mud points to deposition. A good scientist writes a claim, which answers a question in one sentence, and supports it with evidence. Wind, water and weather change the surface in many ways, so our claim can be: wind, water and weather break rock and move it to new places.
| Process | What it does | A clue to look for |
|---|---|---|
| weathering | breaks rock into pieces | cracks, crumbs at the foot of a rock |
| erosion | moves the pieces | muddy water, bare slope with channels |
| deposition | sets the pieces down | piles of sand, mud on a river bank |
| Claim | Evidence | Reasoning |
|---|---|---|
| waves remove sand | castle went flat when water was poured | moving water carries grains |
My claim. Look at a picture of sand dunes, a cracked rock or a muddy river. Write one claim about what changed the land. Add one piece of evidence that you can see in the picture, and one sentence of reasoning that joins the claim to the evidence. Read it to a friend and ask: is my evidence something you can see?