Stratigraphy – Layers of Time in the Earth
Subjects: Science, Social Studies
Grade level: 11-12
Rationale: This lesson introduces students to the concept of stratification as a historical and geological process.
Lesson Duration: 45 minutes
Students will read about the Richard Beene archeological site, which lies near San Antonio, Texas on the Medina River, and watch a short video about stratification. They will then color code the different strata present at the site and answer questions from the reading.
Texas Essential Knowledge and Skills (TEKS):7th Grade
Step 1: Ask Students how we gain information about peoples and cultures from thousands of years ago. Explain that archeologists dig in the earth for artifacts, (objects made or used by man) that help us understand how people of long ago lived.
Step 2: Distribute pages 1 & 2 of the activity, Stratigraphy – Layers of Time in the Earth. Read the text of page 1 aloud with students. Ask students for examples of artifacts they sometimes see on the ground and that future archeologists may find (for example, gum wrappers, marbles, buttons, etc.)
Step 3: Explain that students will view an action video illustrating the stratification process. Before viewing the video, display the following questions (omitting answers) on the board or overhead and read them aloud with students:
Have students go to the Texas Beyond History Digging Through Layers of Time website at http://www.texasbeyondhistory.net/beene/digging/index.phpand click on the See Stratification in Action activity. As they view the video, have them write down the answers to the above questions. After viewing the activity, call for volunteers to read their answers to the questions and discuss.
Step 4: Distribute the stratigraphy diagram handout and colored pencils. Have students complete the worksheet.
Step 5: Have students write their answers to the four questions on the diagram handout.
Modification for Special Learning Needs: Have students color only the sky and trees, and color code only the wide bands on the diagram. The four questions on the handout may be answered aloud.
Student Product: Completed color-coded stratigraphy diagram
Closure: Ask students what one artifact from their lives they would NOT want found by future archeologists and have them explain their answers.
Assessment: Ask students why the deepest layer in an archeological site is usually the oldest.
Extension Activity: Have students read aloud and explain their answers to question #4 (Why do you think people camped at this site over and over again during different time periods?) on the diagram handout.
Texas Beyond History
University of Texas Archeological Research Laboratory
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