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The Rock Cycle:
The Story of a Rock
Download a printable version (PDF)
Overview
Grade Level: 7-9
Background Information:

One of the primary responsibilities of a geologist is to explain how a rock came to be. Using observation of the rock itself, where the rock is located, and a little geologic knowledge, a geologist can recreate a scene in a geologic story.

For example, in central Oregon there is a rock called the Goose Rock Conglomerate. The name of the rock is my first clue to the story of its origins. By calling it a conglomerate, the geologist is limiting the options. It is a sedimentary rock, not igneous or metamorphic. It is made of pebbles or small stones, formed from other rocks. It existed at the surface of the earth in a watery environment and that water had high energy. Either there was a lot of wave action or it was formed in a fast-moving river or stream or as part of a debris flow or landslide. Further investigation of the rock shows me that the pebbles are roughly 2 inches in diameter and well rounded. They are held together by a cement. This helps me to fill in the details of my story. Now I know that these were likely formed in a beach or river mouth environment because the rocks have been well sorted. In a debris flow or landslide, sand, pebbles and boulders all slide together. With a little more regional analysis, I find that I am in the Cretaceous period and that there are deeper ocean water sediments to the west. Now if I close my eyes while standing on the Goose Rock Conglomerate in central Oregon (200 miles from the current coast) I can picture myself on a rocky, wave-lapped beach akin to Pebble Beach. Dinosaurs such as Triceratops rustle through the flowery shrubs to my east, velociraptors swoop through the sky above, and ichthyosaurs and large ammonites are swimming as the sun sets to the west.

Story telling can be used to help students understand the changes a rock undergoes as it passes through the rock cycle. In this activity, students will use more creative story telling to describe the rock cycle. This activity is intended to be used at the end of a unit on rocks and minerals, and may even constitute an assessment of the unit.

Curriculum Suggestion
This lesson combines knowledge of the scientific content about the rock cycle with creative writing and art. You may want to work with language arts and art teachers to present it as an integrated lesson. For instance, if English classes are learning to write narratives, you might require their story to be in the form of a narrative. Or, they might write the story and be graded on writing style by their English teacher and on scientific content by the science teacher.

 
Content Standards
Related National Standards:

This lesson addresses the following National Content Standards found at: http://books.nap.edu/html/nses

 

Content Standard D: As a result of their activities in grades 9-12, all students should develop understanding of:

  • Structure of the earth system
    • Some changes in the solid earth can be described as the 'rock cycle.' Old rocks at the earth's surface weather, forming sediments that are buried, then compacted, heated, and often re-crystallized into new rock. Eventually, those new rocks may be brought to the surface by the forces that drive plate motions, and the rock cycle continues.

Content Standard D: As a result of their activities in grades 9-12, all students should develop understanding of:

  • Geochemical cycles
    • The earth is a system containing essentially a fixed amount of each stable chemical atom or element. Each element can exist in several different chemical reservoirs.
    • Movement of matter between reservoirs is driven by the earth's internal and external sources of energy. These movements are often accompanied by a change in the physical and chemical properties of the matter.
  • Origin and evolution of the earth system
    • Interactions among the solid earth, the oceans, the atmosphere, and organisms have resulted in the ongoing evolution of the earth system.
Extension Web Sites from PBS:

Newtons Apple - Mount Rushmore
This is an activity about weathering and erosion and how they affect different types of rocks.

Newtons Apple - Spelunking
This site includes an activity about weathering in caves.

Standard Deviants - All About Geology
Check out this site for a basic text on different types of rock formation.

Standard Deviants - All About Geology (classroom resources) This site contains activities using rocks. It is especially good for younger students.

Nova - The Curse of T. Rex
If students think they understand the rock cycle, they can go here to test their knowledge!

Activity 1: The Rock Story
Time Allotted:

One class period plus time to complete assignment as homework

 

Materials:

Student Instruction Sheet

Geologic Dictionary, textbooks, and pictures of rocks and rock specimens are helpful

 

Objectives:
  • Students will describe the changes undergone by rocks during the rock cycle.
  • Students will describe the processes that occur during the rock cycle.
  • Students will use creative writing to illustrate their understanding of the rock cycle.
  • Students will develop an understanding of the interconnectedness of the rock cycle.
Watch the AFG Video Segments:

Mountain Building in the Desert - Part 3
During the Mid-Tertiary Deformation, the mountains of southern Arizona were profoundly stretched and thinned.

 

Play This Clip
 Geology of the Gem State
Prehistoric geological forces are responsible for forming the numerous gems and stones for which Idaho is famous.

Note: Clip starts at 'in the beginning, all was igneous.' Stop clip after hearing 'and change the shape from this nice rock to this metamorphic rock'

 

From these videos, have your students discuss the transformation from one rock type to another. As a group, make a draft of the rock cycle (see example at: http://www.cnwl.igs.net/~gvss/gca2a0/website/rock.htm) using the rocks mentioned in the video. Use the following questions to help lead your discussion.

 

Discussion Questions for Video Segment:
  • In the first video, the geologist illustrates how granite can be turned into gneiss. What are some things that might happen to gneiss?
  • Does granite have to turn into gneiss? What else might happen to it?
  • In the second video, they showed a sedimentary rock turning into a metamorphic rock. Does it have to become a metamorphic rock?
  • Is the rock cycle a one-way cycle?

 

Classroom Activity:

The purpose of this activity is for students to write a creative story about a rock as it goes through the rock cycle. This can be done in many formats. Some students have written it as a detective story, a story about someone in the witness protection program, a story about teen angst (so many forces pulling and pushing), a love story, etc. The possibilities are endless. You may want to preface this by reading part of A Rock Grows Up: The Pacific Northwest Up Close and Personal by Randi and Mike Goodrich to illustrate how one might personify a rock (search on Amazon.com to order a copy). This story tells of a young rock, coming up through a subduction zone and being exposed to different forces on the Earth's surface. It is written for fifth graders and is illustrated by a high school student. See the student directions for more specific details.

 

Watch the AFG Video Segment:
Play This Clip

Hiking in Canyon Sin Nombre
The slot canyons and rugged terrain of Canyon Sin Nombre offer many examples of how water and erosion have transformed the desert landscape.

Note: Students may watch this segment after writing their stories. Clip starts at 'So Canyon Sin Nombre translates…' Stop clip after hearing 'mere few years for a geologist.'

 

Discussion Question for Video Segment:
  • How can rocks tell a geologic story?

Curriculum Suggestion: You may wish to compare different types of conglomerates. The one in the video resulted from a flash flood. See the introduction for another type of conglomerate. One way that the Canyon Sin Nombre Conglomerate is different from the Goose Rock Conglomerate is that it has a wider variety of grain sizes. Note cobbles bigger than a fist mixed with smaller pebbles. These clues are invaluable to geologists in interpreting geologic stories.

 

Suggested Assessment:
Score each of the following categories on a scale from 0-4
4 = Very well done
3 = Generally good
2 = Needs work
1 = Poor
0 = Not enough to grade.

 

Category Points
Proper and liberal use of terminology (magma vs lava; intrusive/extrusive etc.)  
Accurate and thorough description of the processes and conditions that cause you to change  
Good physical description of what you would look like at each stage of your rock cycle and the proper name that would be given at each phase  
Creativity  
Total Points:  

 

Activity 2: Rock Around the Rock Cycle
Time Allotted:

45 minutes

 

Materials:

Paper (Butcher paper, Poster Paper, Construction paper, etc.)

Markers or crayons

Student Instruction Sheet

 

Objectives:
  • Students will show connections between different stages of the rock cycle by making a diagram.
  • Students will illustrate a particular pathway a rock can take through the rock cycle.
Classroom Activity:

Once students have written their story, they can illustrate it. Some will chose to draw a direct copy of the rock cycle diagram (see an example) and then will show their rock's pathway while others will be more creative. See the student instructions for more details.

 

Suggested Assessment:
Score each of the following categories on a scale from 0-4
4 = Very well done
3 = Generally good
2 = Needs work
1 = Poor
0 = Not enough to grade.

 

Category Points
Does it contain all the elements and processes necessary for your rock to complete its journey?  
Does it contain all the correct rock names in the right places?  
Is it neat and easy to read?  
Creativity  
Total Points:  

 
Activity 3: Identifying Rocks (optional)
Time Allotted:

15 minutes

 

Materials:

Rock samples or pictures of rocks

 

Objectives:
  • Students will identify rocks.
  • Students will match rocks with the appropriate phase of the rock cycle.
  • Students will show how certain rocks can become other rocks.
Classroom Activity:

This part of the lesson may be done in one of several ways.

 

Have students find rocks to glue onto their posters to illustrate the different phases of the rock cycle.

OR

Have students choose from a collection of rocks to insert rocks into their posters. You might request that they design places on their posters for the rocks that don't require them to glue to rocks to the poster. For instance, they might design little shelves or include plastic baggies, and then they can display your rocks and easily return them.

OR

Use this as a mini-assessment for your rock unit. Ask students to choose three rocks from your collection that illustrate their story (make one sedimentary, one igneous, and one metamorphic). You can grade them on the accuracy of their rock identification. Do they get the right names on the right rocks? Do they at least identify sedimentary, igneous, and metamorphic rocks correctly?

 

Related Web Sites:

Igneous Rock Identification Exercise
This site provides detailed information about identifying and classifying igneous rocks. It also includes similar information for metamorphic rocks and minerals.

JMU Geology Department Geologic Web Sites
A collection of web sites with a wealth of information about rocks and rock identification.