Wednesday, October 22, 2014

Erosion experts visit 4th grade

Recently, fourth graders had a visit from Ely and Stacey from Clean Water Services. This visit built on a previous class visit and field visit to Fern Hill wetlands in our ongoing study of erosion.

Students used a Tualitin watershed model table. Ely explained it as a "3D map" to help test theories about erosion. The model allowed the students to simulate what happens when rain or other types of precipitation mix with contaminants on the ground.

The students then tested mitigation strategies such as grasses, sedges and rushes. They modelled these with felt and other materials like foam to see if erosion and runoff could be better controlled.



The second part of the visit was an erosion slide show which depicted real-life examples of the effects of erosion.

What is erosion?
The movement of rocks and soil by: 
Wind-happens in dry areas with little vegetation, farm fields and deserts
wind moves sediment around, changes the forms of rocks


Ice-snow settles and never melts away, glaciers are formed over many years and as they slowly melt they slide over land and break up rock
glaciers also form valleys

Water-river is cutting through ground as it flows. The reason for a muddy river is soil, sediment being moved by erosion

Waves- over time waves wear away rock and move sediment of landforms along the coast

Gravity-heavy weight, cliffs, slopes, avalanches, landslides, steep slopes cause land to erode









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