Name:_____________________________________
Class:___Earth Science_______
Period/Block:________________________________
Date:______________________________________
Class Notes: S6E5h: Describe soil as consisting of weathered rocks and decomposed organic
material.

What is weathering?
What are the types of weathering?
Weathering breaks rock into smaller
and smaller pieces, such as sand, silt,
and clay. These smaller, loose pieces
are called sediment.
Two types of weathering:
Mechanical- occurs when rocks are broken
apart by physical processes. This means
that the overall chemical makeup of the
rock stays the same.
Example: Ice and plant roots pry rocks
apart changing the size of the rock.
Chemical- occurs when chemical
reactions dissolve the minerals in rocks or
change them into different minerals
Example: Natural acids, such as carbonic acid,
and acids from dying plants dissolve minerals
in rock.
Effects of weathering
What is soil? How is it made?


•
•
•
•
It reshapes the Earth’s surface by:
Wearing mountains down to hills
Forming caves
Soil is a mixture of weathered rock,
decayed organic matters, mineral
fragments, water, and air.
Weathering breaks down rocks or minerals
on our surface, it creates a layer of rock
sediments.
Over time, the sediments break down even
more creating very fine (small) particles.
Plants and animals add organic matter, the
wastes and dead plant material, to the rock
fragments.
What is soil composed of?
Soil Profile
Soil is made of rock and mineral fragments,
organic matter, air and water.
The layers of different soil are called
__horizons_____.
Horizon A is also called _topsoil___________.
On the top of horizon A are leaves, twigs and other
organic matter called _litter_____.
Horizon _A_ has the darkest soil because of the
decayed organic matter.
B Horizon has soil that is lighter in color because
less __ORGANIC_____ matter.
B Horizon gets materials from the A horizon by the
process of _LEACHING________.
C Horizon is the lightest and __THICKEST_____
soil layer.
The C Horizon contains partially weathered
_ROCK____ and very little organic matter.
What is found beneath the horizons?
_BEDROCK_________: a layer of solid rock that
contributes/adds to soil; also called
__PARENT____ rock.
List in order from largest to smallest.
SAND, SILT, CLAY
Sediment (weathered rock/mineral) sizes in soil
4 factors that affect soil formation
Words to know:
Mechanical weathering
Chemical weathering
Soil, humus, litter, horizon, soil profile, and
leaching
1.
2.
3.
4.
5.
Climate
Slope
Vegetation
Types of rock
Amount of time rock has been weathering
Directions: Vocabulary Flip book