Natural Weathering

By Nina BergoldBy Nina Bergold

What is Natural Weathering? Natural weathering, or physical weathering, is the term used to Natural weathering, or physical weathering, is the term used to

describe the process of the shaping of specific elements by the means describe the process of the shaping of specific elements by the means of natural forces.of natural forces.

Natural weathering, like many other forces, comes in many different Natural weathering, like many other forces, comes in many different forms, such as erosion, oxidation, the freeze-thaw process, and many forms, such as erosion, oxidation, the freeze-thaw process, and many more.more.

Some famous examples of the results of natural weathering are the Some famous examples of the results of natural weathering are the Grand Canyon, Bryce Canyon, and Monument Valley.Grand Canyon, Bryce Canyon, and Monument Valley.

Natural weathering, like all forces in nature, doesn’t happen overnight. Natural weathering, like all forces in nature, doesn’t happen overnight. It takes millennia of constant exposure to the elements for a landscape It takes millennia of constant exposure to the elements for a landscape to change. to change.

Wind Erosion Wind erosion happens when a rock Wind erosion happens when a rock

is exposed to constant wind for is exposed to constant wind for long periods of time. Over many long periods of time. Over many years, particles that are exposed to years, particles that are exposed to the wind are blown away, gradually the wind are blown away, gradually sculpting the beautiful rock sculpting the beautiful rock formations that make places like formations that make places like Monument Valley so famous.Monument Valley so famous.

The results of wind erosion are The results of wind erosion are commonly seen in places with little commonly seen in places with little or no vegetation.or no vegetation.

Another example of this kind of Another example of this kind of erosion are sand dunes, both on the erosion are sand dunes, both on the beach and the desert.beach and the desert.

Water Erosion Water erosion happens when a Water erosion happens when a

landscape is exposed to water, from landscape is exposed to water, from melting snow to rivers, for long melting snow to rivers, for long periods of time. As time passes, the periods of time. As time passes, the water acts like a natural knife; it water acts like a natural knife; it cuts through the landscape, making cuts through the landscape, making itself a little path.itself a little path.

The Grand Canyon, the world’s The Grand Canyon, the world’s deepest canyon, would never be the deepest canyon, would never be the same without centuries of being same without centuries of being exposed to the Colorado River exposed to the Colorado River cutting through it. cutting through it.

Of course, water erosion doesn’t Of course, water erosion doesn’t always result in iconic canyons. It’s always result in iconic canyons. It’s a farmer’s worst enemy, as it can a farmer’s worst enemy, as it can destroy soil and crops, as the destroy soil and crops, as the picture below illustrates.picture below illustrates.

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are needed to see this picture.

Oxidation Oxidation is the reaction between the Oxidation is the reaction between the

molecules in metal and oxygen, hence molecules in metal and oxygen, hence the name. the name.

Tarnishing and rusting, which are two Tarnishing and rusting, which are two forms of oxidation, are a huge problem forms of oxidation, are a huge problem not only for people who work with not only for people who work with silver and iron, but also for car owners. silver and iron, but also for car owners.

Since the paint is always exposed to the Since the paint is always exposed to the elements, the paint, without proper care, elements, the paint, without proper care, will eventually peel and fall off, which will eventually peel and fall off, which exposes the other layers of the car, exposes the other layers of the car, which will rust and cause major which will rust and cause major problems.problems.

Another good example of oxidation is Another good example of oxidation is the exposure of a bitten apple to the air. the exposure of a bitten apple to the air. After a few minutes, the inside of the After a few minutes, the inside of the apple turns brown, which is why they apple turns brown, which is why they should be eaten right away.should be eaten right away.

The Decaying Process Since objects like the tombstones Since objects like the tombstones

shown here, are constantly exposed to shown here, are constantly exposed to the elements, they eventually become the elements, they eventually become weathered and they start to decay.weathered and they start to decay.

In fact, the building we’re in is In fact, the building we’re in is decaying as I speak, but it may not decaying as I speak, but it may not seem like it because it’s constantly seem like it because it’s constantly maintained. maintained.

The tombstones, however, are The tombstones, however, are replaced very infrequently. They are replaced very infrequently. They are only replaced after they decay so only replaced after they decay so much that the words are illegible and much that the words are illegible and when they’re very crumbly and when they’re very crumbly and fragile. fragile.

The decaying process varies from The decaying process varies from place to place. If someone were place to place. If someone were buried in a very wet place with lots of buried in a very wet place with lots of humidity, they and their gravestone humidity, they and their gravestone would decay faster than if one were would decay faster than if one were to be buried in a drier environment.to be buried in a drier environment.

Discussion Questions

Based on what you now know, what conclusions can you draw from what I just taught you?

When you look at something that has rust or tarnish on it, what process did it go through?

What do you think our world would be like with no natural weathering? Explain what would happen in detail.

You don’t have to go to a national park or even a graveyard to see natural weathering in action. What examples of natural weathering can one find in his/her everyday life?

What would decay faster, a gravestone that’s constantly exposed to rain or one that is in the middle of the desert?

Links and Resources

http://www.http://www.stonecaretechniquesstonecaretechniques.com/8_m..com/8_m.htmhtm http://www.weathering.org/weathering/natural.http://www.weathering.org/weathering/natural.htmhtm http://en.http://en.wikipediawikipedia.org/.org/wikiwiki/Weathering/Weathering http://library.http://library.thinkquestthinkquest.org/20035/physical..org/20035/physical.htmhtm http://www.http://www.tulanetulane..eduedu/~/~sanelsonsanelson/geol111/weathering./geol111/weathering.htmhtm

Pictures are from Google.Pictures are from Google.