National Park Service
Breaking & Moving
Rocks in nature are constantly being worn down by the forces of weathering and erosion.
Instructions: Explore the different forces of weathering and erosion below by clicking on each image. When you are done can you come up with a definition for the words weathering and erosion? How are the forces of weathering similar and/or different from the forces of erosion below?
Forces of Weathering
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Forces of Weathering: Water
Water breaks down the glue in sandstone creating holes like these solution pits.
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Forces of Weathering: Tree Roots
Tree roots pry down, making cracks grow. This breaks the rock.
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Forces of Weathering: Ice
As water freezes it expands, breaking rocks by creating large cracks in the cliff walls.
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Forces of Weathering: Wind
The wind picks up sand grains that polish the rocks by breaking off loose grains on the surface.
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Forces of Weathering: Animal Scat
Animal scat contains acids that break down the minerals in the sandstone.
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Forces of Erosion: Gravity
Gravity pulls loose rocks off of the canyon walls, moving them downhill during rock falls.
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Forces of Erosion: Water
Flowing water during flash floods has the power to move LOTS of rocks and sand.
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Forces of Erosion: Wind
Wind can move small sediment, like sand grains and pebbles.
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Forces of Erosion: Humans
Humans move tons of rocks to build roads, trails, and buildings.
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Forces of Weathering: Lichens
The tiny threads of lichens growing on the surface pry sand grains off. The lichens also create chemicals that slowly break down minerals in rocks.
Forces of Erosion
Many canyons are carved by rivers, like the Colorado River. However, the canyons in the monument are different; they were carved by flash floods. You might wonder how floods can move that much rock. Watch the video below to learn more about flash floods in the monument.