weathering Flashcards
what is weathering
The break down of large rocks, into smaller pieces of sediment, which is left in the same area that the
rock use to be in
name there three types of weathering
Mechanical weathering
Chemical weathering
Biological weathering
what is Mechanical weathering
Mechanical weathering is the physical breakdown of a material without altering its its chemical composition
what are the three types of Mechanical weathering
Freeze- thaw action
Rocks peel (Exfoliation)
Expansion and contraction
explain the Freeze- thaw action
water collects in the rock crack
water freezes and expands , forcing crack to widen
ice thaws , contracts and water goes deeper into the cracks again
repeat expansion and contraction causes further cracks until the rock breaks
explain the Rocks peel (Exfoliation
rock surface heats up and expands
rock surface cools and contracts
joints form around the outer part of rock
these rocks break eventually
explain the Expansion and contraction
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what is Chemical weathering
Chemical weathering is the breakdown of rock though chemical process, like acid rain
what kind of environment does Chemical weathering mostly occur
chemical weathering happens most in humid, tropical regions where there is a lot of moisture in the air.
how is acid rain formed anyhow does it affect plants
Rainwater absorbs carbon dioxide and Sulphur dioxide from the atmosphere and from plant roots and it forms a weak carbonic or sulphuric rain
or
when fossils fuels burn an give off gases , the gases combine with water in the atmosphere and it falls back to earth as acid rain or snow
when this rain seeps through permeable rock ,it corrodes the rock
what type of rock does chemical weathering affect the most Why?
what does corroded lime stone form
lime stone
because lime stone is very permeable.
(has large pores to allow water
to sink in.)
When lime stone
dissolves underground it can
form amazing caves like the
Cango caves.
what is Biological weathering
biological weathering involves weathering caused by animals , plants and people
what causes Biological weathering
1 )when decomposing plant material makes rain water more acidic, this acid reacts
with the chemicals in the rock and breaks it down.
2)PLANT ROOTS
Trees and plant roots grow into
cracks of rocks as they grow, they break up
the rock.
3) BACTERIA AND LICHEN
Moss and lichen on rocks also absorb moisture from rain, and keep the water on the surface of the rocks for longer.
4) ANIMALS
Animals burrowing through the earth and
weakening the soil and rock particles.
What is Stalagmites and stalagtites
Stalagmites are when calcium carbonate is deposited on the floors of caves
stalactites are when calcium carbonate is deposited on the roofs of caves
