5 minute checkNovember 6, 2013

What is the difference between a constructive and a destructive force?

4.3 - The student will describe how landforms are the result of a combination of constructive and destructive processes.

Two Types of Forces Destructive Forces: processes that

destroy landforms.◦ 2 types: Slow (weathering) and Fast (Erosion)◦ Ex. landslides, volcanic eruptions, earthquakes,

floods

Constructive forces: forces that build up an existing landform or create a new one. ◦ Caused by: water, gravity, wind and glaciers.◦ Ex: deposition, landslides, volcanic eruptions,

floods

Destructive forces – destroy and wear away landmasses through processes like weathering and erosion.

◦ Weathering – wearing by wind, precipitation, freezing/thawing◦ Erosion – wearing down & carrying away of land by natural

forces

Destructive forces are those that are recycling the Earth, like Earthquakes and plate movement.

One example is when wind erodes or takes away some of the sand on a sand dune or beach.

Farming is a destructive process, because the soil has to be dug up and moved around in order to grow plants. Mining is another destructive process, because we dig holes into the earth or blow up parts of the earth and/or caves in order to get what we want.

Constructive and Destructive processes

Weathering Weathering: a slow, destructive force that

breaks rocks into smaller pieces called sediments. Can be by a physical (mechanical) or chemical process.

Weathering Pictures

Mechanical weathering: the breaking of rock into smaller pieces by forces due to gravity, ice, plant roots, or other physical forces.

Chemical Weathering: the changing of materials in a rock by chemical processes.

Erosion Erosion: the destructive movement of

materials away from one place by wind, water, ice and gravity.

Wave Erosion- caused by waterWind Erosion (Dust Storm)

Grand Canyon Video

Landslides

Landslides: occur when gravity quickly pulls rock and dirt downhill.

Floods Floods: a great flow of water over an area

that is usually dry land.

Volcanic Eruptions

Volcano: an opening in the Earth’s crust through which steam, lava and ashes erupt.

Cause both destructive and constructive changes to landforms.

Mount St. Helens

Saint Helen’s Before

Saint Helen’s After

Mount St. Helens Video

Volcanoes can be constructive, but also destructive…

Earthquakes

Earthquakes: the shaking of Earth’s surface caused by the release of energy along a fault.

San Andreas Fault, California

Constructive forces – shape earth’s surface by building up mountains, volcanoes and other landmasses caused by plate movements. It makes positive changes!

One example of a constructive process is when sand is deposited onto a river bank by the running water. This builds up the river bank, making it higher.

Another example of a constructive process is a volcano erupting. This builds up the land around the volcano, making it higher.

Constructive and Destructive processes

Constructive Process Any type of geological event where land is

uplifted.

Uplift- the movement of fault block (normal fault)

Mountain Building- the convergence of two plates

Constructive forces built up the Himalayas

Erosion & Deposition

Deposition: the placing of materials in a new place (constructive force).

Ex. Sandbars

Water Erosion & Deposition River Delta-

Deposits of sediment at the mouth of the Mississippi River creating new land called a delta.

Wind Erosion & Deposition Sand Dunes- sand is moved by wind

Desert Sand Dunes Ocean Sand Dunes

The Bernard Glacier in Alaska's Saint Elias Mountains

Grand Canyon – sandstone rock

New York – lichen on granite; secrete chemicals that break down rock

Is it a Constructive & Destructive Force?

5 minute checkNovember 7, 2013

Give an example of a Constructive and a Destructive force?

4.3 - The student will describe how landforms are the result of a combination of constructive and destructive processes.

Two Types of Forces Destructive Forces: processes that

destroy landforms.◦ 2 types: Slow (weathering) and Fast (Erosion)◦ Ex. landslides, volcanic eruptions, earthquakes,

floods

Constructive forces: forces that build up an existing landform or create a new one. ◦ Caused by: water, gravity, wind and glaciers.◦ Ex: deposition, landslides, volcanic eruptions,

floods

Destructive Process Any type of geological process that destroys or moves land

Weathering- the process of breaking down rock into smaller pieces ◦ Chemical- acid rain breaks down rocks

Example: Granite gravestones and statues

◦ Mechanical- the use of mechanical force to break apart rocksExample: plant growing in sidewalk

Destructive Process Any type of geological process that destroys or moves land

Erosion- the process of moving sediment◦ Glacial Erosion- glaciers push rocks and move them downhill

Example: Alaska glaciers and alpine glaciers

◦ Wind Erosion- wind picks up and carries sedimentExample: moving sand dunes

◦ Gravity Erosion- gravity forces rocks and large landmasses downhillExample: landslides

Constructive forces: forces that build up an existing landform or create a new one. ◦ Caused by: water, gravity, wind and glaciers.◦ Ex: deposition, landslides, volcanic eruptions,

floods

Constructive Forces

Today we are going to look at images from Nevada and discuss whether or not they are constructive or destructive forces

Is it a Constructive & Destructive Force?Let’s look at examples here in Nevada

pine tree eroded by wind

Nevada’s Great Basin National ParkA- Constructive B-Destructive

Is it a Constructive & Destructive Force?Let’s look at examples here in Nevada

pine tree eroded by wind

Nevada’s Great Basin National ParkA- Constructive B-Destructive

Is it a Constructive & Destructive Force?Let’s look at examples here in NevadaLake Tahoe – created by a normal faultA- Constructive B-Destructive

Is it a Constructive & Destructive Force?Let’s look at examples here in NevadaLake Tahoe – created by a normal faultA- Constructive B-Destructive

Is it a Constructive & Destructive Force?Let’s look at examples here in NevadaSierra Nevada MountainsA- Constructive B-Destructive

Is it a Constructive & Destructive Force?Let’s look at examples here in NevadaSierra Nevada MountainsA- Constructive B-Destructive

Is it a Constructive & Destructive Force?Let’s look at examples here in NevadaSpring Mountain Range (Mt. Charleston)A- Constructive B-Destructive

Is it a Constructive & Destructive Force?Let’s look at examples here in NevadaSpring Mountain Range (Mt. Charleston)A- Constructive B-Destructive

Is it a Constructive & Destructive Force?Let’s look at examples here in NevadaRed Rock Canyon A- Constructive B-Destructive

Is it a Constructive & Destructive Force?Let’s look at examples here in NevadaRed Rock Canyon A- Constructive B-Destructive

Is it a Constructive & Destructive Force?Let’s look at examples here in NevadaValley of FireA- Constructive B-Destructive

Is it a Constructive & Destructive Force?Let’s look at examples here in NevadaValley of FireA- Constructive B-Destructive

Is it a Constructive & Destructive Force?Let’s look at examples other than NVGrand CanyonA- Constructive B-Destructive

Is it a Constructive & Destructive Force?Let’s look at examples other than NVGrand CanyonA- Constructive B-Destructive

5 minute checkNovember 8, 2013

What are all the names for the hot stuff that comes out of volcanos?

4.3 - The student will describe how landforms are the result of a combination of constructive and destructive processes.