- Take a notes packet from book shelf by chalk board.

- Take out hwk - What is weathering?

Don’t copy the words typed in this color.

ObjectivesObjectives::•You will learn about weathering and its You will learn about weathering and its

effects.effects.•You will learn to explain what You will learn to explain what mechanical mechanical

weatheringweathering is and how it occurs. is and how it occurs.•You will learn to explain what You will learn to explain what chemical chemical

weatheringweathering is and how it occurs. is and how it occurs.•You will learn how You will learn how climateclimate affects affects

weathering.weathering.

Surface processes that work to break Surface processes that work to break down rock are called __________.down rock are called __________.

• _________ breaks rock into smaller and smaller pieces, such as ____, ____, and _____. These smaller, loose pieces of rock are called _________.

• The terms The terms ____, , ____, and , and _____ are are used to describe specific sizes of used to describe specific sizes of sediment.sediment.

• ______ grains are largest______ grains are largest• ______ grains are medium sized______ grains are medium sized• ______ grains are smallest______ grains are smallest

weathering

Weathering

sandsiltclay

sedimentsclay silt sand

sand

claysilt

• __________ wears mountains down to hills

• Rocks at the top of mountains are broken down by weathering, and the sediment is moved downhill by _______, ______, ____, and _____.

• 2 types of weathering:

____________

____________

Weathering

gravity waterice wind

___________________ occurs when ___________________ occurs when rocks are broken apart by physical rocks are broken apart by physical

processes. This means that the processes. This means that the overall chemical makeup of the rock overall chemical makeup of the rock

stays the same.stays the same.

Mechanical weathering

_____________, _______________, and _____________, _______________, and ___________ are some of the things ___________ are some of the things

that can mechanically weather rock. that can mechanically weather rock.

Growing plants burrowing animalsexpanding ice

• ____________________ occurs in occurs in temperate temperate and cold and cold climates climates where water where water enters enters cracks in cracks in rocks and rocks and freezesfreezes. .

Ice wedging

• When water enters cracks in road pavement and freezes, it forces the pavement apart. This causes ________ to form in roads.potholes

• This cycle of freezing and

thawing not only breaks up rocks,

but also can break up roads and highways.

• As rock is broken apart by mechanical weathering, the amount of rock surface exposed to _______ and ______ increases. oxygen water

_________________ occurs when _________________ occurs when chemical reactions dissolve the chemical reactions dissolve the

minerals in rocks or change minerals in rocks or change them into different minerals. them into different minerals.

This type of weathering This type of weathering changeschanges the the chemical compositionchemical composition of the rock, of the rock,

which can weaken the rock. which can weaken the rock.

Chemical weatheringChemical weathering

Carbon dioxide + Carbon dioxide + Water = ____________Water = ____________

____________ reacts ____________ reacts with minerals such with minerals such as calcite, which is as calcite, which is the main mineral the main mineral

that makes up that makes up limestone.limestone.

Over many Over many thousands of years, thousands of years, carbonic acid has carbonic acid has

weathered so much weathered so much limestone that limestone that

caves have formed.caves have formed.

Carbonic acidCarbonic acid

Carbonic acidCarbonic acid

Chemical Chemical weathering also weathering also

occurs when occurs when naturally naturally

formed _____ formed _____ come in contact come in contact

with other with other rocks. rocks.

For example:For example:Feldspar + Feldspar +

Natural acids = Natural acids = KaoliniteKaolinite

acidsacids

Some _____ and Some _____ and ______________ give ______________ give off _____ that also off _____ that also

dissolve minerals in dissolve minerals in rock. rock. When these When these minerals dissolve, minerals dissolve,

the rock is the rock is weakened.weakened.

Eventually, the rock Eventually, the rock will break into will break into smaller pieces.smaller pieces.

rootsrootsdecaying plantsdecaying plants

acidsacids

Material + Water + Material + Water + Oxygen = __________Oxygen = __________

Rust is caused byRust is caused by __________ when the __________ when the material exposed to material exposed to water and oxygen water and oxygen

contains iron.contains iron.

OxidationOxidation

oxidationoxidation

One common One common example of this type example of this type of weathering is the of weathering is the

alteration of the alteration of the iron-bearing mineral iron-bearing mineral

magnetite to a magnetite to a rustlike material rustlike material called limonitecalled limonite.

Oxidation of Oxidation of minerals gives some minerals gives some

rock layers a red rock layers a red color. color.

______ is the pattern of weather ______ is the pattern of weather that occurs in a particular area that occurs in a particular area over many years. over many years.

In _________ and ____ In _________ and ____ climates, where climates, where

freezing and thawing freezing and thawing are frequent, are frequent,

__________ weathering __________ weathering rapidly breaks down rapidly breaks down

rock through the rock through the process of ice process of ice

wedging.wedging.

ClimateClimate

temperate temperate cold cold

mechanical mechanical

________ weathering is more ________ weathering is more rapid in _____, ____ climates. rapid in _____, ____ climates.

Lack of moisture in deserts and low Lack of moisture in deserts and low temperatures in polar regions slow temperatures in polar regions slow

down chemical weathering. down chemical weathering.

Chemical Chemical wetwetwarm warm

__________ also can affect the rate of weathering in a particular climate.

In wet climates, for example, marble weathers more rapidly than granite.

Rock typeRock type

1. ___________ includes processes that break down rock.

2. ___________ affects Earth’s landforms.3. During ___________ weathering, rock is

broken apart, but it’s not changed chemically.4. Plant roots, burrowing animals, and expanding

ice all ________ rock.5. During ________ weathering, minerals in rock

dissolve or change to other minerals.6. Agents of ________ weathering include

natural acids and oxygen.

Weathering

Weatheringmechanical

weatherchemical

chemical

We are going to go for a walk around the school!!! See how

many real life examples of mechanical

weathering you can find!!! Be ready to

share them when we return!