A
what is weathering?
it is the breaking down of rocks
what is physical weathering?
when things such as wind or rain break rocks down
what is chemical weathering?
when a rock breaks down when minerals in the rock are changed chemically.
what are horizons?
they are layers of soil
What is exfoliation?
when outer layers of rocks peel off
what does the word thaw mean?
to melt
Explain how plants can cause physical weathering?
A plant's roots can force their way through small cracks in a rock, as the roots grow, the cracks get wider, causing the rock to break into pieces
True or False:
Soil Horizons are different from place to place
true
what does the word expand mean?
to take more space/ stretch
What is wind abrasion?
it is the wearing away of rocks by blowing sand
Explain what happens in Freezing and Thawing?
water from melted rock or rain enters small cracks of rocks and when it freezes it expands which causes the crack to widen, breaking the rocks into smaller pieces
How does Abrasion cause physical weathering?
winds can carry bits of sand and it can break down the softer parts of rocks or even wear away rock by using the sharp edges of the sand (think of sand paper)
Each horizon has its own what?
properties
what are 4 causes of physical weathering?
Freezing and Thawing
Plants
Exfoliation
Abrasion
How does iron become rusty over time?
How does carbonic acid form?
when carbon dioxide combines with rainwater.
Decaying plant and animal matter puts what into the soil.
carbon dioxide
what is humus?
it is decayed plant or animal material
Most water in rivers and soil contain what?
Acids
Oxygen, acids, and carbon dioxide can react with the minerals in rocks and cause what?
Chemical Weathering