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Disappearing Rocks
How Erosion Creates Ventifacts

data | hook | main | background & resources | student

Author Contact Information

Elissa Elliott, TEA 1998/1999, bruingirl91@hotmail.com

Overview
Various types of erosion have formed our Earth as it is today. Students will learn what things cause erosion--in this parcticular case, water--and how different surfaces erode differently.

  • The students will predict the outcomes of erosion on different materials.
  • The students will describe ways of preventing erosion.
  • The students will recognize erosion and will predict what type of erosion caused it.

    • Ventifact research, pictures, lesson, resource compilations are by Elissa Elliott.

    Activity idea adapted from Windows to the Universe web site.

    Grade Level/Discipline
    Grades 4 - 6, but may be adapted for older students

    National Standards

  • Structure of the Earth System, Content Standard D
  • Earth’s History, Content Standard D
  • Abilities Necessary to Do Scientific Inquiry, Content Standard A
  • Natural and Human-Induced Hazards, Content Standard F
  • Science and Technology in Local, National, and Global Challenges, Content Standard F

    • Pre-activity set-up

  • Gather materials
  • Make copies of student handout
  • Set up work areas

    • Materials

  • Rock and mineral samples--5 for each group (variety of hardnesses, such as shale, limestone, quartz, and
  • two sizes of salt pellets, see http://www.rockhounds.com/rockshop/hardness1.html)
  • Student Lab Sheet
  • Plastic jar with lid
  • water
  • clock or timer
  • scale
  • paper towels

    • Time Frame
    One 45-minute class period to do activity, part of another for discussion...more class periods if extensions are done

    Engagement and Exploration (Student Inquiry Activity)
    Show pictures included in this lesson plan to students. Explain what a ventifact is. Ask for other evidences of erosions (mountains, valleys, sand dunes, cracks in sidewalks--temperature erosion, sand on the shore, etc.). What things cause erosion? [Chemicals (acid rain), Wind, Ice (glaciers), Water (rivers), Temperature (sidewalks, roads)]

    Hand out the Student Lab Sheet. Explain the procedure to the students. Encourage them to predict what will happen to each rock (or mineral) and the extent to which something will happen. Surfaces react differently to forces.

    After students are done with the activity, ask a spokesperson to record the results on a class overhead or on a class chart on the board. Have the remaining lab partners answer the analysis questions.

    Explanation (Discussing)
    Once the students have filled in the classroom chart, briefly discuss any anomalies. You may have to wait until the next day to discuss, given the time taken with the lab.

    Go over the answers to the questions.

    1) This will be your hardest rock/mineral (whatever that is).

    2) This will be your softest rock/mineral (whatever that is).

    3) The softer the rock, the more "washable" it is. The water can tear it apart easier.

    4) The shaking in water represented a rainstorm (or pounding under ocean waves)

    5) Whenever it rains, the rain causes the soil to move or wash away. The looser the soil, the more it moves. Maybe little streams are formed through the grass; maybe the soil is washed away in certain areas to leave little mounds in your backyard.

    6) We used 2 salt pellets to show there is a difference in erosion when the object sizes are different. The larger the surface area, the more erosion. Think of it this way, there’s more area to erode.

    7) The rock used to be sitting on the top of a sheet of ice. The wind blew, causing the area around the rock to slowly disappear, leaving the ice under the rock intact and forming a pinnacle.


    (Picture of ice table ventifact)

    Elaboration (Polar Applications)
    Antarctic scientists working in the Dry Valleys see the effects of erosion all of the time. Glaciers cause erosion. Ventifacts are stones that have been eroded. Douglas Quin, one such scientist on his way to study Taylor Glacier, sees the "Singing Rocks" known as ventifacts. The students would enjoy the audio with this (http://www.home.pon.net/quin/antarctica/journal5/nov28.html).

    Another great visual and auditory resource is the Erosion Channel at the Exploratorium (http://www.exploratorium.edu/complexity/exhibit/erosion.html)

    Most Dry Valley research centering on some form of erosion makes a study of how the glaciers erode and cause erosion (http://quest.arc.nasa.gov/antarctica/background/NSF/valleys.html).

    Extensions: For a more comprehensive unit, focusing on all types of erosion, I would strongly suggest the following unit plan at http://www.lessonplanspage.com/ScienceSSMDUnitOnErosion46.htm . For other lesson plan ideas, please see the compiled web sites under Resources

    Exchange (Students Draw Conclusions)

    Evaluation (Assessing Student Performance)
    Compile pictures of other erosions. See web sites in Resources for available pictures. Ask students what happened. How might the problem be corrected?

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