Lab 5: Droughts of the Past

The lab activity described here was created by Betsy Youngman of Phoenix Country Day School and LuAnn Dahlman and Sarah Hill of TERC for the EarthLabs project.

Summary and Learning Objectives

America's most famous drought resulted in an environmental disaster called the Dust Bowl. From 1931 to 1939, a five-state region of the Great Plains received little rain and experienced horrendous dust storms that stripped the land of its topsoil. The event went on to shape the demographics of the American West as thousands of people migrated out of the plains and on to western states.

In this activity, students will watch a PBS video and/or interact with the video's companion website. They will also examine maps and animations that show the distribution of drought patterns over the past 300 years; these maps were reconstructed from environmental records. Finally, students will examine the amount of time different areas spend in drought.

After completing this investigation, students will be able to:

  • Discuss whether the "Dust Bowl" of the 1930s could reoccur
  • View and analyze historical patterns of drought across the continental the United States
  • Examine and interpret maps and graphs depicting drought severity and duration
  • Describe paleoclimatology data that are collected and the methods of processing them
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Context for Use

This lesson builds on student's understanding of drought. It delves into historical drought patterns and the science of paleoclimatology. The lesson can complement student's study the 1930s in history class. Computers with Internet access and Quicktime capabilities are required.

Estimated Time Required

  • Part A: 50 minutes (more if you show the PBS video), reading can be done as homework.
  • Part B: 50 minutes
  • Part C: 30-50 minutes, begin in class and finish for homework
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Activity Overview and Teaching Materials

In Part A, students get an overview of the drought that resulted in the "Dust Bowl" of the 1930s. You may decide to show part of the PBS video "Surviving the Dust Bowl" in class. It is available for purchase from the PBS shop. It is also available in many public libraries. The most relevant segments of the video for this lesson are Chapters 3 and 4. The lab Web pages direct students to explore the video's companion website and view streaming video of personal accounts from people who lived through the experience.

Students examine droughts of the recent past in Part B. In order to gain a sense of the variability of drought events, students choose and view several maps of drought distribution from the past 10 years. Then students examine a set of graphs and maps graphs and maps (Acrobat (PDF) 903kB Oct23 18) that show notable droughts over the past century. They also use the North American Drought Atlas's online animation to examine drought patterns from the past 300 years and compare drought maps using instrument data and reconstruction data from three years NADA Historical Comparison Maps (Acrobat (PDF) 2.7MB Oct31 18). Finally, they watch a brief film about Tree Ring Analysis to learn more about the proxy data used to reconstruct the ancient maps used in the animation. In the Optional Extension for Part B, students are walked through how to find their own maps from the North American Drought Atlas to compare the different data sets.

Part C explores the frequency and severity of drought, first by consulting maps that show drought distribution during different time periods and then by river basin. This lesson concludes with students performing Internet searches to find out about evidence for medieval megadroughts of southwestern North America.

Printable Materials

You may want to provide a hard copy of the activity sheet (Acrobat (PDF) 36kB Dec18 18) on which students can record their answers. A

of the activity sheet that includes suggested answers is also available. Educators are encouraged to customize the questions and add new ones to meet specific learning goals in your location.

Teaching Notes and Tips

The American Dust Bowl is an enormous topic. As most students will have studied some of the social and historical aspects of the event in their history classes, it is presented rather briefly in this lesson. Teachers may choose to show the PBS video or use other online and library resources to investigate this topic in more depth. As possible take time to hold a discussion on the environmental and technological factors that led to the disaster: these include the invention of the mechanized plow and the disruption of the native prairie sod. Exploring contributors to this past disaster will help students identify factors that could result in a recurrence.

Part C has students using a variety of maps and graphs. Remind students to be sure to read the legends carefully. When students are examining drought frequency by basin, you may decide to split the class into 18 groups and assign each group one basin to review. The final section of the lesson on medieval megadroughts can be completed as a homework assignment.

Assessment

Compare student answers to the Stop and Think questions with the answers provided. In Part B, when students choose maps from the CPC Drought monitor site, they may want to download and save a series of maps to make their own collage or animation to show spatial or temporal patterns of drought. To assess Part C, you may assign students to select and analyze the temporal patterns of drought for one river basin and write a summary paragraph.

State and National Science Teaching Standards

Additional Resources

Background Information

Pedagogic Considerations

Students generally live day-to-day. Consequently, they have little awareness of how climate has impacted the survival of the human species. This lesson's introduction to the great droughts of the past centuries will help them to visualize the linkages between climate and life on Earth.

Content Extension

For students who are interested in the historical aspects of the American Dust Bowl, the book "The Worst Hard Time" by Timothy Egan has excellent environmental as well as social information. Read the book review from the NY Times.

After viewing the Living History video clips, students may also want to conduct an interview with a relative who remembers the 1930s.

Consider teaming up with the American History teacher(s) at your school so that students can explore the environmental causes and effects of the Dust Bowl disaster in their science course at the same time as they explore the social and economic impacts in history class. Another excellent video from the History Channel entitled "Black Blizzard" can be purchased from the History Channel online shop.