Science 6

Study Pack #8

Today’s Goals…

I can explain what weathering is. I can identify different causes of weathering.

Weathering or Erosion?

An old tombstone that is hard to read A mountain after a landslide Sand dunes Rocks broken into tiny pieces A crack in a sidewalk A ditch where water has once flowed

Weathering

A process that breaks rocks into smaller piecesMechanicalChemical

Mechanical Weathering

Breaks rocks into smaller pieces WITHOUT changing them chemicallySmaller pieces are identical to the original rock

Two causes are: Ice (or Frost) WedgingPlants and Animals

Ice Wedging

Water from rain or snow seeps into cracks in rocks The water freezes and expands making the cracks

open further until the rock breaks

Plants and Animals

Roots grow into cracks in rocks where water collects and force the rock apart

Some animals burrow through rocks and break them apart

Chemical Weathering

Occurs when the chemical composition of a rock changes

Causes are Natural acidsOxygen

Natural Acids

Carbonic acid (water and carbon dioxide) can dissolve certain rocks

Some plants produce acids that can affect rocks

Oxygen

When oxygen reacts with the iron in rocks it turns them orange or red

Assignment

Frayer Model for Vocabulary Weathering

Definition – In your own wordsCharacteristics – You may want to include types hereExamplesNonexamples