Download Weathering and soil formation

Wilson 
Found in a
streamCracksfrost
Surfacesediment
WEATHERING AND SOIL
FORMATION
PRE- NOTES QUESTIONS
1. How do water and air cause rocks to crumble?
2. Why is soil one of our most important resources?
3. How are weathering and soil formation related?
MINI LAB- WHAT’S THE DIFFERENCE?
1.
2.
3.
4.
2 small cups filled with water
Put 1 sugar cube in one cup
Put 1 tsp granulated sugar in one cup
Using 2 separate spoons stir the cups at the same
rate
5. Observe which type of sugar dissolves more
quickly
• Did the sugar dissolve at the same rate?
• Which do you think would wear away faster a large
or small rock? Explain.
WEATHERING
• Weathering- the breakdown of rock into
smaller and smaller pieces
• 2 TYPES:
1. Mechanical Weathering- the breakdown of rock
into smaller pieces by physical means (changing
appearance, not composition)
2. Chemical Weathering- the chemical breakdown
of rocks and minerals into smaller pieces
TYPES OF MECHANICAL WEATHERING
1. Ice – Water expands when it freezes.
• Ice Wedging- when water forces a rock open
wider over time
2. Wind- When wind blows against rock, it wears
away at the surface of the rock.
TYPES OF MECHANICAL WEATHERING
• Abrasion- the action of
rocks and sediment
grinding against each
other and wearing away
exposed surfaces
3. Water- When rocks get
carried in rivers, they bump
into each other becoming
river rocks.
4. Gravity- When one rock
falls on another, as they
tumble down a mountain
TYPES OF MECHANICAL WEATHERING
5. Plants- Plants can
easily break rocks.
• Ex: Tree roots can
crack sidewalks.
6. Animals- Animals
burrow through soil and
move particles around.
• Ex: Earthworms,
groundhogs
TYPES OF CHEMICAL WEATHERING
• Chemical weathering breaks down rocks and
minerals into new substances.
1. Water- Rock is broken down by water.
• Ex: Sugar cube, chalk, granite
2. Acid Precipitation- (Acid Rain)
• Contains acid due to pollution
• Ex: Sulfuric, nitric, and carbonic acid
TYPES OF CHEMICAL WEATHERING
3. Acid in Groundwater- Water underground can
contain acid, which reacts with rocks and minerals.
• Ex: Limestone
4. Acid in Living Things- Some organisms produce
acid, which can break down rock.
• Ex: Lichens
5. Air- Rocks and elements react with oxygen to form
rust.
• Oxidation- chemical reaction in which an element like iron
reacts with oxygen to form an oxide
CHEMICAL OR
MECHANICAL???
VIDEO- IDENTIFYING THE TYPE OF
WEATHERING!