Key Idea: When continental plate material from one plate presses against another plate, the continental plate material is forced upward, forming mountains.

Students are expected to know that:

  1. Continental plate material makes up continents, oceanic plate material makes up ocean basins, and the top part of any plate can be made of either oceanic or continental plate material or continental plate material in some places and oceanic plate material in other places.
  2. Continental plate material is made of rock that is less dense and much thicker than oceanic plate material.
  3. When two plates press together, if one plate has plate material at its edge that is less dense than the edge of the other plate, the less dense plate material will crumple upward, creating a bend or fold in the plate material but not causing the plate to break into smaller pieces of rock. If the plate material is approximately the same density on both edges, the edges of both will crumple upward.
  4. When continental plate material from one plate presses against oceanic plate material from another plate, the continental plate material crumples up over the oceanic plate material.
  5. As continental plate material from one plate presses against continental plate material from another plate, the edges of both plates crumple up, creating a bend or fold in the plate material but not causing the plate to break into smaller pieces of rock.
  6. The result of a plate crumpling up is mountains, which are composed of the continental plate material that has been folded upward.
  7. The crumpling up of plate material reduces the area of the earth’s surface covered by a plate.
  8. New mountains have formed throughout earth’s history, and mountains continue to develop as plates move and press together.

Boundaries:

  1. Students are not expected to know that continental plate material from one plate can sink under other continental plate material from another plate.
  2. Students are not expected to know that when two plates press together, plate material breaks (e.g., faults occur) as well as bends.
Frequency of selecting a misconception

Misconception
ID Number

Student Misconception

Grades
6–8

Grades
9–12

PTM146

Earth's plates cannot bend (AAAS Project 2061, n.d.).

50%

45%

PTM039

Mountains form by the piling up of pieces of rock (AAAS Project 2061, n.d.).

50%

45%

PTM140

Continental plate material is only pushed upward when it pushes into continental plate material on another plate (AAAS Project 2061, n.d.).

37%

35%

PTM129

Continental plate material is pushed beneath oceanic plate material when two plates push together (AAAS Project 2061, n.d.).

25%

22%

PTM133

When two plates push together and continental plate material is at the edge of both plates, one plate will stop moving and the edge of the other plate will be pushed upward (AAAS Project 2061, n.d.).

22%

23%

PTM142

When a plate with continental plate material at its edge pushes into another plate, the continental plate material is always pushed downward (AAAS Project 2061, n.d.).

15%

18%

PTM131

When two plates push together, the edges of the plates break into small pieces (AAAS Project 2061, n.d.).

16%

15%

PTM132

When two plates push together and continental plate material makes up the edge of both plates, both plates will be pushed downward (AAAS Project 2061, n.d.).

15%

13%

PTM130

When two plates push into each other, both plates will stop moving (AAAS Project 2061, n.d.).

12%

13%

PTM144

New mountains developed in the past, but no new mountains are developing today (AAAS Project 2061, n.d.).

13%

12%

PTM145

There have been times when mountains have developed in the past, but only occasionally (i.e., not continuously) (AAAS Project 2061, n.d.).

14%

10%

PTM143

All mountains that exist today formed when the earth first formed (AAAS Project 2061, n.d.).

10%

7%

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.