Topic: Weathering, Erosion, and Deposition

Below is a list of key ideas related to Weathering, Erosion, and Deposition. For each key idea, you will find a list of sub-ideas, a list of items, results from our field testing, and a list of student misconceptions. After clicking on a tab, click on it again to close the tab.

The surface of the earth is changed as rock material is broken, carried, and dropped in new locations.

Students are expected to know that:

  1. Wind and water (including glaciers, and water from rain, rivers, streams, and oceans) break, carry, and drop rocks as they move.
  2. The rock that is broken includes earth’s solid rock layer (bedrock) and loose rocks that range from large boulders to rocks so small that they can only be seen with a microscope (i.e., smaller than sand). These rocks are carried and dropped in new locations by wind and water, and they can hit and break other rocks as they are moved.
  3. The breaking, moving, and dropping of rock material makes mountains smaller, changes the shape of valleys and makes them deeper, and changes the shape of cliffs and coastlines and paths of rivers. The motion of wind and water causes these changes by removing rock material from one place and adding rock material in another. These changes can occur anywhere on or near earth’s surface, including under lakes, rivers, and oceans.
  4. Both slow-moving and fast-moving water can break and can move rocks, and both large volumes and small volumes of water can move and break rocks. Both slow-moving and fast-moving wind can move and break rocks.
  5. Rock can be broken when plant roots grow into cracks in the solid rock layer and cracks in loose rocks.
  6. Because water expands when it freezes, rock can be broken when water freezes in cracks in rocks.
  7. Rock can be worn away by dissolving. As water moves across and through the solid rock layer and loose rocks, it dissolves minerals that make up the rock and carries them away. The rock left behind then has less mass.
  8. Minerals that are dissolved in water can stay dissolved as the water flows over long distances, or the minerals can come out of solution and be deposited as solid minerals along the water’s path.

Boundaries:

  1. The terms “weathering” and “erosion” are not used. All processes that involve the breakdown of rock material are described as “wearing away.”
  2. Students are not expected to know the different effects of wind and water on different rock types.
  3. Students are not expected to know which minerals dissolve easily in water, how minerals are dissolved, or how dissolved minerals are deposited as solid minerals.
  4. Students are not expected to know that in addition to the breakdown processes that are mentioned specifically, rocks also break down in other ways (such as by chemical reactions that change minerals).
  5. Students are not expected to distinguish mechanical from chemical processes of wearing away rock material.
  6. This topic exclusively addresses wearing away of rock material. Students are not assessed on the wearing away, moving, and dropping of soil (as distinct from rock material) as part of this topic.
  7. At the middle school level, this topic treats wind and water themselves as the agents of erosion, and it does not specifically address the fact that rocks carried by the wind and water are the primary cause for erosion.
  8. Ideas about earth’s outer rock layer are assessed in the topic of plate tectonics and, therefore, are not assessed as part of this topic.
Percent of students answering correctly (click on the item ID number to view the item and additional data)
Item ID
Number

Knowledge Being Assessed

Grades
6–8

Grades
9–12

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WE028003

Wind and water can change the shape of a coastline and the path of a river.

60%

65%

WE007002

Both the growth of plant roots and the freezing of water can break earth's solid rock layer.

60%

64%

WE027002

Wind and water can change the earth's surface over time by wearing away mountains and making valleys deeper.

59%

61%

WE011002

Ice that freezes in the cracks of the solid rock layer, and glaciers that move against the solid rock layer, can change the surface of the earth by breaking the solid rock layer.

56%

64%

WE015003

Water can make a valley deeper by breaking the solid rock layer and carrying loose rocks away from the valley.

60%

58%

WE012003

Both a small stream and ocean waves can erode the solid rock of a cliff over time.

55%

57%

WE042002

Water can break rocks, carry them, and deposit them in new locations.

55%

57%

WE009002

Water can wear away rocks by breaking off pieces of rocks, and water can wear away rocks by dissolving minerals in rocks.

54%

55%

WE064001

A rock in a stream can get smaller by colliding with other rocks or by some of it dissolving in water.

51%

59%

WE016004

Both the growth of plant roots and the freezing of water can break off pieces of rock from earth’s solid rock layer.

48%

57%

WE060001

The shape of a valley floor changes when ice breaks rocks as it moves (as in a glacier) and also when water freezes in cracks in the rock of the valley floor.

49%

56%

WE014004

Wind, water, and the growth of plant roots can wear away the solid rock of a valley.

49%

56%

WE053001

Wind can both break and move rocks the size of a grain of sand.

50%

45%

WE029003

Wind can change earth’s solid rock layer and the loose rock material on top of the surface of the earth by breaking rocks and moving them to new locations.

47%

45%

WE052001

A very strong wind can both break and move a rock the size of a baseball.

40%

43%

WE032003

Water can dissolve rock material, move the dissolved material to a new location, and deposit the dissolved rock material as solid rock.

35%

39%

WE051001

A very strong wind can both break and move rocks the size of boulders.

24%

26%

Frequency of selecting a misconception

Misconception
ID Number

Student Misconception

Grades
6–8

Grades
9–12

WEM085

Wind cannot break grains of sand (AAAS Project 2061, n.d.).

41%

45%

WEM023

The growth of plant roots cannot break rock (AAAS Project 2061, n.d.).

45%

38%

WEM018

Wind cannot break rock (AAAS Project 2061, n.d.).

41%

41%

WEM010

Wind can carry small rocks (e.g., sand) but never carries large rocks (e.g., fist-sized) (AAAS Project 2061, n.d.).

37%

34%

WEM077

A small stream cannot wear away the solid rock of a cliff over time (AAAS Project 2061, n.d.).

36%

34%

WEM060

Water cannot deposit dissolved rock as solid rock (AAAS Project 2061, n.d.).

31%

38%

WEM089

Wind cannot break solid rock (AAAS Project 2061, n.d.).

33%

35%

WEM088

Wind cannot carry rock and deposit it in a new location (AAAS Project 2061, n.d.).

31%

32%

WEM016

Water cannot dissolve rocks (AAAS Project 2061, n.d.).

29%

24%

WEM080

Water cannot break rocks (AAAS Project 2061, n.d.).

26%

26%

WEM110

Rocks cannot break by colliding with other rocks (AAAS Project 2061, n.d.).

27%

21%

WEM040

Wind and water cannot wear away solid rock to change the path of a river (AAAS Project 2061, n.d.).

23%

22%

WEM081

Water cannot carry rocks and deposit them in a new location (AAAS Project 2061, n.d.).

23%

22%

WEM039

Wind and water cannot wear away solid rock to change the shape of a coastline (AAAS Project 2061, n.d.).

23%

19%

WEM061

Ice can only break rock when it moves (as in a glacier) (AAAS Project 2061, n.d.).

23%

18%

WEM084

Wind cannot move grains of sand (AAAS Project 2061, n.d.).

18%

16%

WEM078

Ocean waves cannot wear away the solid rock of a cliff over time (AAAS Project 2061, n.d.).

16%

18%

WEM074

Water cannot make a valley deeper (AAAS Project 2061, n.d.).

15%

15%

WEM038

Wind and water cannot wear away the solid rock of a mountain (AAAS Project 2061, n.d.).

15%

13%

WEM037

Wind and water cannot wear away solid rock to make a valley deeper or wider (AAAS Project 2061, n.d.).

14%

15%

WEM019

Glaciers cannot break rock (AAAS Project 2061, n.d.).

15%

13%

WEM065

Water that freezes in cracks in rock cannot break the rock (AAAS Project 2061, n.d.).

15%

13%

WEM017

Liquid water cannot break rock (AAAS Project 2061, n.d.).

10%

11%

WEM029

Landforms look similar today as they did many millions of years ago. For example, a river on earth today hasn’t changed over time (Dove, 1998; Trend, 1998).

8%

9%

WEM090

Water cannot wear away solid rock (AAAS Project 2061, n.d.).

7%

8%

Frequency of selecting a misconception was calculated by dividing the total number of times a misconception was chosen by the number of times it could have been chosen, averaged over the number of students answering the questions within this particular idea.

The loose rock material on the surface of the earth broke off from the solid rock layer (bedrock) that makes up the outer portion of the earth.

Students are expected to know that:

  1. Broken rocks form a relatively thin layer of loose rock material on the surface of the earth.
  2. Most of the loose rocks on the surface of the earth originally came from the breaking of the solid rock layer (bedrock) that makes up the outer portion of the earth. These rocks continue to break, such that large loose rocks (e.g., boulders), are broken down to even smaller rocks (e.g., sand).
Percent of students answering correctly (click on the item ID number to view the item and additional data)
Item ID
Number

Knowledge Being Assessed

Grades
6–8

Grades
9–12

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WE037004

All loose rock material came from earth's solid rock layer

62%

66%

WE022004

Very large rocks the size of boulders can come from breaking off from earth's solid rock layer and from breaking off from larger rocks.

55%

60%

WE021002

Both large and small loose rocks on the surface of the earth were once part of earth's solid rock layer.

35%

40%

Small changes to the surface of the earth caused by wind and water can add up to large changes over long periods of time (i.e., over thousands to millions of years).

Students are expected to know that:

  1. Wind and water continuously wears away, moves, and drops rock material, even if it is by such small amounts that the changes cannot be seen without the help of instruments.
  2. Changes to the earth’s surface by wind and water that occur over relatively short time periods can add up to very large changes over long time periods. Because mountains and valleys are so large, and because even changes that occur over a year are relatively small compared to the size of the mountain or valley, it often takes many millions of years for wind and water to cause large changes to their shape and size.
  3. As a result of the continuous action of wind and water, all places on earth look different today from how they looked in the past and from how they will look in the future.
Percent of students answering correctly (click on the item ID number to view the item and additional data)
Item ID
Number

Knowledge Being Assessed

Grades
6–8

Grades
9–12

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WE038002

The continuous movement of wind and water changes the size of mountains over many millions of years

58%

64%

Frequency of selecting a misconception

Misconception
ID Number

Student Misconception

Grades
6–8

Grades
9–12

WEM038

Wind and water cannot wear away the solid rock of a mountain (AAAS Project 2061, n.d.).

12%

11%

WEM029

Landforms look similar today as they did many millions of years ago. For example, a river on earth today hasn’t changed over time (Dove, 1998; Trend, 1998).

12%

11%

WEM051

Landforms can change in size, but not by the motion of wind and water (AAAS Project 2061, n.d.).

11%

9%

Frequency of selecting a misconception was calculated by dividing the total number of times a misconception was chosen by the number of times it could have been chosen, averaged over the number of students answering the questions within this particular idea.

The surface of the earth is changed as rock material is broken, carried, and dropped in new locations.
-and-
Small changes to the surface of the earth caused by wind and water can add up to large changes over long periods of time (i.e., over thousands to millions of years).

These items have been aligned to more than one key idea. To view the sub-ideas click on a key idea below.

  • The surface of the earth is changed as rock material is broken, carried, and dropped in new locations.

    Students are expected to know that:

    1. Wind and water (including glaciers, and water from rain, rivers, streams, and oceans) break, carry, and drop rocks as they move.
    2. The rock that is broken includes earth’s solid rock layer (bedrock) and loose rocks that range from large boulders to rocks so small that they can only be seen with a microscope (i.e., smaller than sand). These rocks are carried and dropped in new locations by wind and water, and they can hit and break other rocks as they are moved.
    3. The breaking, moving, and dropping of rock material makes mountains smaller, changes the shape of valleys and makes them deeper, and changes the shape of cliffs and coastlines and paths of rivers. The motion of wind and water causes these changes by removing rock material from one place and adding rock material in another. These changes can occur anywhere on or near earth’s surface, including under lakes, rivers, and oceans.
    4. Both slow-moving and fast-moving water can break and can move rocks, and both large volumes and small volumes of water can move and break rocks. Both slow-moving and fast-moving wind can move and break rocks.
    5. Rock can be broken when plant roots grow into cracks in the solid rock layer and cracks in loose rocks.
    6. Because water expands when it freezes, rock can be broken when water freezes in cracks in rocks.
    7. Rock can be worn away by dissolving. As water moves across and through the solid rock layer and loose rocks, it dissolves minerals that make up the rock and carries them away. The rock left behind then has less mass.
    8. Minerals that are dissolved in water can stay dissolved as the water flows over long distances, or the minerals can come out of solution and be deposited as solid minerals along the water’s path.

    Boundaries:

    1. The terms “weathering” and “erosion” are not used. All processes that involve the breakdown of rock material are described as “wearing away.”
    2. Students are not expected to know the different effects of wind and water on different rock types.
    3. Students are not expected to know which minerals dissolve easily in water, how minerals are dissolved, or how dissolved minerals are deposited as solid minerals.
    4. Students are not expected to know that in addition to the breakdown processes that are mentioned specifically, rocks also break down in other ways (such as by chemical reactions that change minerals).
    5. Students are not expected to distinguish mechanical from chemical processes of wearing away rock material.
    6. This topic exclusively addresses wearing away of rock material. Students are not assessed on the wearing away, moving, and dropping of soil (as distinct from rock material) as part of this topic.
    7. At the middle school level, this topic treats wind and water themselves as the agents of erosion, and it does not specifically address the fact that rocks carried by the wind and water are the primary cause for erosion.
    8. Ideas about earth’s outer rock layer are assessed in the topic of plate tectonics and, therefore, are not assessed as part of this topic.
  • Small changes to the surface of the earth caused by wind and water can add up to large changes over long periods of time (i.e., over thousands to millions of years).

    Students are expected to know that:

    1. Wind and water continuously wears away, moves, and drops rock material, even if it is by such small amounts that the changes cannot be seen without the help of instruments.
    2. Changes to the earth’s surface by wind and water that occur over relatively short time periods can add up to very large changes over long time periods. Because mountains and valleys are so large, and because even changes that occur over a year are relatively small compared to the size of the mountain or valley, it often takes many millions of years for wind and water to cause large changes to their shape and size.
    3. As a result of the continuous action of wind and water, all places on earth look different today from how they looked in the past and from how they will look in the future.
Percent of students answering correctly (click on the item ID number to view the item and additional data)
Item ID
Number

Knowledge Being Assessed

Grades
6–8

Grades
9–12

Select This Item for My Item Bank

WE056001

The solid rock of mountains was being worn down by wind and water millions of years ago, and it is being worn down by wind and water today.

68%

70%

WE026004

Moving water continuously wears down earth's solid rock layer, which changes the shape of a valley even if you cannot see it happening.

63%

69%

WE063001

Wind wore away the solid rock of valleys millions of years ago and continues to wear away the solid rock of valleys today.

59%

66%

WE031002

It takes many millions of years to wear away a mountain until it is almost flat.

59%

66%

WE062002

The solid rock of valleys was being worn away by wind millions of years ago, and it is being worn away by wind today.

61%

60%

WE025005

Wind and water can wear away the solid rock of a mountain over many millions of years.

58%

61%

WE018003

Moving water continuously wears down earth's solid rock layer whenever water is moving over the rock, even if you cannot see it happening.

45%

52%

WE019003

Whenever wind moves against the solid rock of a mountain, a little bit of the rock is worn away, even if you cannot see it.

42%

43%

WE048001

Water can gradually wear away the solid rock of mountains as much as thousands of feet over many millions of years.

36%

42%

WE039002

Water can gradually wear away the solid rock of river valleys as much as thousands of feet over millions of years.

36%

40%

WE059001

Rain wears away very small amounts of the rock of a cliff whenever the rain falls.

37%

37%

WE050001

Wind can gradually wear away the solid rock of river valleys as much as thousands of feet over millions of years.

35%

37%

WE049001

Wind can gradually wear away the solid rock of mountains as much as thousands of feet over many millions of years.

36%

35%

Frequency of selecting a misconception

Misconception
ID Number

Student Misconception

Grades
6–8

Grades
9–12

WEM107

Wind can wear away the solid rock of mountains only a small amount (feet or inches) over millions of years, not thousands of feet (AAAS Project 2061, n.d.).

55%

55%

WEM095

Wind can make a valley deeper by only a small amount (feet or inches) over millions of years (AAAS Project 2061, n.d.).

55%

55%

WEM094

Water can wear away only a small amount of a mountain's height (feet or inches) over millions of years (AAAS Project 2061, n.d.).

55%

53%

WEM091

It takes rain a long time to wear away solid rock, even very small amounts that you cannot see (AAAS Project 2061, n.d.).

54%

53%

WEM096

Water can wear down the solid rock of a river valley only a small amount (feet or inches) over millions of years (AAAS Project 2061, n.d.).

54%

52%

WEM030

Wind can only wear down solid rock over long time periods. Changes are not happening over short time periods (i.e., a day or a year) (AAAS Project 2061, n.d.).

50%

48%

WEM086

Moving water can only wear down solid rock over long time periods. Changes are not happening over short time periods (i.e., a day or a year) (AAAS Project 2061, n.d.).

47%

42%

WEM067

Moving water can only change the surface of the earth over long time periods. Changes are not happening over short time periods (i.e., a day or a year) (AAAS Project 2061, n.d.).

33%

27%

WEM105

Wind is wearing away the solid rock of valleys today but did not wear away the solid rock of valleys in the past (AAAS Project 2061, n.d.).

27%

21%

WEM104

Wind wore away the solid rock of valleys in the past but is not wearing away the solid rock of valleys today (AAAS Project 2061, n.d.).

25%

20%

WEM022

Wind and water only change the surface of the earth during rare events, such as huge storms (AAAS Project 2061, n.d.).

20%

20%

WEM050

It only takes hundreds of years for wind and water to wear away the solid rock of a mountain (bedrock) so that the mountain is almost flat (AAAS Project 2061, n.d.).

18%

17%

WEM070

Solid rock was being worn away by wind many years ago, but it is no longer being worn away by wind today (AAAS Project 2061, n.d.).

16%

16%

WEM062

Wind and water changed the surface of the earth in the past but are no longer changing the surface of the earth (AAAS Project 2061, n.d.).

16%

12%

WEM071

Solid rock is currently being worn away by wind, but it was not being worn away by wind many years ago (AAAS Project 2061, n.d.).

13%

13%

WEM051

Landforms can change in size, but not by the motion of wind and water (AAAS Project 2061, n.d.).

12%

10%

WEM063

Wind and water are changing the surface of the earth today but did not change the surface of the earth in the past (AAAS Project 2061, n.d.).

10%

13%

WEM028

Erosion can wear away solid rock a little bit but could never have a big effect on the surface of the earth such as leveling mountains or carving valleys (AAAS Project 2061, n.d.).

11%

10%

WEM106

It takes only a short time (tens of years) for wind and water to wear down the solid rock of a mountain so that the mountain is almost flat (AAAS Project 2061, n.d.).

11%

8%

WEM092

Rain cannot wear away solid rock (AAAS Project 2061, n.d.).

9%

9%

WEM072

Wind cannot wear away solid rock (AAAS Project 2061, n.d.).

9%

10%

WEM090

Water cannot wear away solid rock (AAAS Project 2061, n.d.).

9%

7%

WEM087

Moving water cannot wear down solid rock (AAAS Project 2061, n.d.).

8%

7%

WEM038

Wind and water cannot wear away the solid rock of a mountain (AAAS Project 2061, n.d.).

7%

11%

WEM068

Moving water cannot wear away solid rock to change the shape of a valley (AAAS Project 2061, n.d.).

4%

8%

Frequency of selecting a misconception was calculated by dividing the total number of times a misconception was chosen by the number of times it could have been chosen, averaged over the number of students answering the questions within this particular idea.