Physical and Chemical and Weathering

Physical and Chemical and Weathering

Name three causes of physical weathering.

* Wind

* Water

a. Flowing

b. Glacier

c. Ice

* Plants

Wind causes Weathering

• Have you ever been outside on a windy day? Have you ever felt the sting of sand or other particles on your face on those windy days? Well, imagine what that wind and those particles are doing to the land around you or around the world over vast amounts of time. Let’s view and discuss some pictures taken of wind weathered earth materials.

Wind

Flowing Water weathers the earth by moving

materials and wearing away earth materials

“V” shaped valleys are made by fast flowing water.

GlaciersGlaciers are slow moving frozen

rivers that grind and wear away the earth in the path they travel.

“U” shaped valleys are made by glaciers.

IceIce weathers by the process

called “frost-wedging.” Water fills cracks in earth materials and then when it freezes, it

expands, cracking the material that held it.

Then when the temperature warms up, the water fills the new formed cracks and then freezes when temps lower and cracks the materials even more. Can you see how this process can wreak havoc on the environment? Notice how large potholes will grow this winter in the street near your house. This is due to frost-wedging.

PlantsRoots grow into rocks, causing

them to crack.

                                      Lichen on boulder, Cartersville, GA

                                      Close-up of lichen, Stone Mountain GA

Wind, Water, Ice

Name two causes of chemical weathering.

• Rusting

• Acid Precipitation

Rusting

• As iron in rock, etc. rusts, it flakes off. Over great amounts of time, the earth material can flake off in great amounts, thus weathering rocks and even mountains.

Weathering Rind, Wilhite Formation, eastern Tennessee

Acid Precipitation

The Taj Mahal used to be sparkly white, but acid rain has given it its

yellowish-brown hue.

Just as acid precipitation has weathered the Taj Mahal and the gargoyle in the previous slide, acid precipitation eats away at natural rock, mountains, etc. and over time can wear mountains away.

Think about all the ways the earth is weathered.

Think about all the ways that weathering can and has changed the “face” of the earth.

Make a Venn Diagram that compares/contrasts physical and chemical weathering. Do your best. Your Venn Diagram will be graded. The next slide will show you how to set up your diagram.

ChemicalPhysical

List differences in the circles where they don’t overlap. List similarities inside the area where the circles do

overlap.