4-ESS2-1

Why Do Rivers Curve

Description:  A meandering river is a great example of a phenomenon of water changing the shape of land. When it is surrounded by steep rock a river rarely curves but when it open up in large valleys it will weave back and forth. Water on the outside of the river will travel faster and erode the land more quickly. Eventually it will curve too much and lose speed. A stream table can be used to model a meandering river.

Web Resource: Meander - Wikipedia

Rio-cauto-cuba

 

How Was The Grand Canyon Formed?

Description:  The Grand Canyon is a mile-deep and was carved by the Colorado River over millions of years. This phenomenon shows how consistent weathering and erosion over a long period of time can radically shape the earth. Even though the work of the Colorado took millions of years this is relatively rapid compared to the billions of years of deposition revealed by the Canyon. A trip down into the Grand Canyon is literally a trip back in time written in the rocks.

Web Resources: Grand Canyon National Park, Grand Canyon - Wikipedia, Grand Canyon: Location, Formation & Facts - LiveScience

 

Biological Weathering

Description:  The roots of certain trees are able to break rocks over time.  This is one type of biological weathering that can be seen around the world.  Rocks can also be broken down by bacteria, algae, lichen, and small animals.  Weathering of a sidewalk or the headstones in a cemetery are great places to find this phenomenon.  

Web Resources:  The Geological Society

Biological weathering, Harrison Rocks - geograph.org.uk

Biological weathering, Harrison Rocks - geograph.org.uk