Whether or Not It’s Weathering! An Introduction to and Interactive Assessment About Weathering and Erosion.

Whether or Not It’s Weathering!An Introduction to and Interactive Assessment About Weathering and Erosion.

Weathering

• Weathering is the action of rock being broken down by elements such as rain and wind.• There are 3 types of weathering processes:• Mechanical – the physical breakdown of rock where the rock’s chemical

composition does not change.• Chemical – the breakdown of rock where the chemical and/or mineralogical

composition is changed.• Biological – the breakdown of rocks due to living organisms.

Mechanical Weathering

The physical breakdown of rock where the rock’s chemical composition does not change.Elements of Mechanical Weathering include water (rain or rivers), ice, wind, temperature, and pressure.• In rivers, rocks are moved by water and

hit each other, causing them to break off pieces.

• The Twin Arches in Tennessee, South Arch shown right, show how wind has eroded the weakest sediments to leave behind stronger rock.

Chemical Weathering

The breakdown of rock where the chemical and/or mineralogical composition is changed.• Hydration is the addition of

hydrogen. Water is added to a rock and reacts with the minerals, causing a change in the composition of the rock.

• Oxidation is the addition of oxygen. A change of color is often noted. An example would be rusting!

Biological Weathering

The breakdown of rocks due to living organisms.• Organisms can cause mechanical

and chemical weathering.

• Roots of trees that wedge into cracks can cause enough pressure to break the rock apart (mechanical).

• Organisms like moss can grow on rock. They create a weak acid that can weather down the rock chemically.

Erosion

Erosion is the transportation of

sediments.• When rocks are weathered, the

loose sediment is “eroded,” or transported, and is deposited somewhere else.

• Rivers that turn several times are formed that way because of eroded sediment that builds up on the sides of the river, forcing the flow in a different direction.

• Over long periods of time, structures like hills or dunes can form due to a build up of eroded sediment.

Review

• Weathering is the process by which rocks are broken down.• Mechanical is the physical break down of rocks without changing their

chemical composition.• Chemical is the break down of rocks where their chemical and mineralogical

composition is changed.• Biological is the break down of rocks aided by organisms like tress and moss.

• Erosion is the transportation of sediment.• Deposition is when sediment settles down in a new area.

Quiz Time!!

• Everyone get into your group and use one clicker per group!

• Once I ask the question out loud, you have one minute to discuss your answer choice with you group. Once you have made a decision, click the letter on your clicker that matches your answer choice on the screen.

• Make sure to keep your voices low so other groups cannot hear you! The group with the most points at the end will earn 5 extra credit points on their next quiz!

What is Weathering?

A) The transport of sediment from once place to another.

B) The breakdown of rock by processes such as rain, wind, and animals.

C) The word used to decide if something is one thing or another.

What is Erosion?

A) The transport of sediment from once place to another.

B) The breakdown of rock by processes such as rain, wind, and animals.

C) The breakdown of rock by living organisms.

What is the difference between mechanical and chemical

weathering?A) Chemical weathering is the breakdown of sediment whereas mechanical weathering is the breakdown of rock by machines.

B) Mechanical weathering is the breakdown of rock by processes like wind whereas chemical weathering is the breakdown of rock that changes its chemical or mineralogical composition.

C) Chemical weathering is where acids are introduced by humans to an area to remove rock whereas mechanical weathering is when rock is broken down by process such as wind.

Which weathering process is about living organisms and their effect on

rocks.A) Erosion

B) Mechanical Weathering

C) Deposition

D) Chemical Weathering

E) Biological Weathering

What process would “rusting” fall under?

A) Mechanical Weathering

B) Erosion

C) Biological Weathering

D) Deposition

E) Chemical Weathering

Sorry. Try Again!

You Are CORRECT!

How Did You Do?

• If you answered 0-2 correctly, make sure to review the material again. Making flash cards can help you remember the difference between each term!• If you answered 3-4 correctly, you did very well. Make sure to review

the material, especially the material you answered incorrectly!• If you answered all 5 correctly, you did a fantastic job! Make sure to

review the material so you do not forget!