A Wonderleaf question
How do waterfalls form?
a real page from the book
Waterfalls form when a river runs across rock layers that break down at different speeds. The weaker layer is scraped and dissolved sooner, while a tougher cap remains for a while. When the overhanging edge loses support, pieces fall away, and the river drops over the new cliff.
At the bottom, falling water stirs stones and sand into a drilling swirl, scooping a plunge pool. As the weak layer keeps wearing back, the lip breaks again and again, so a waterfall can creep upstream and leave a narrow gorge behind it.
Wonder words
- erosion
- caprock
- gorge
- gravity
Try it out
In the sink, let tap water run over a small pile of crumbs and watch the soft bits move first.
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