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The Power of Potions

The Power of Potions - by Viki Babcock
Photo of soldiers (middle/high school science)
Students learn the science behind some traditional Zulu medicinal plants and mushrooms used by warriors. They perform a simple paper chromatography lab as an introduction to chemical separation and identification.
Estimated class time

One class period (preferably block scheduling)

Lesson Objectives

Students will:
  • Assess information about a historical battle through reading information from a website

  • Relate modern scientific analysis techniques to an understanding of traditional herbal medicine

  • Perform a simple chromatography lab

  • Analyze lab results
Materials needed

  • Internet access

  • Copies of Paper Chromatography lab handout

  • Lab equipment for each pair of students including:

    • 3 strips of chromatography (or filter) paper (approximately 2cm x 12 cm)
    • 3 beakers (250 ml)
    • 3 straws
    • tape
    • water, isopropyl alcohol, acetone
    • leaf samples (spinach leaves work well, or you might try Coleus, or have students bring in leaf samples of their own)
    • coin
    • pencil
    • colored pencils

  • Video clips are available on the SECRETS OF THE DEAD: Day of the Zulu website, but if you wish to purchase the complete program, visit PBS Shop for Teachers http://shop.pbs.org/teachers/products/SEDE204

Teaching Strategy

Photo from Day of the Zulu

Teachers!
Video clips for your students are available here.

Video Clips
  1. Describe a scenario of a battle between two armies-one armed with firearms and the other armed with stabbing spears and sticks with knobs on them. Ask students which army they think would be most likely to win the battle and why. Accept and discuss all responses

  2. Direct students to SECRETS OF THE DEAD: Day of the Zulu Web site at http://www.pbs.org/wnet/secrets/ case_zulu/index.html. Have the class work in pairs as they read through the Background and Clues and Evidence pages. Also instruct them to work through the Interactive activity, Watch the Battle, discussing responses to the questions with their partners. Each pair of students should generate a list of advantages for both the British and the Zulu armies based on the information from the site.

  3. Discuss their responses. Lead the discussion to the advantages provided by the Zulu medicine men. Explain how scientific analysis of the plants used in Zulu medicine reveals real chemicals that were responsible for the desired reactions. One type of scientific test performed on the plants was chromatography, a way to isolate and identify the different chemicals that make up a substance. Inform the class that they will be performing a very simple type of chromatography using plants. Provide each pair of students with the Paper Chromatography lab handout and the necessary equipment. While the students are waiting for their test results, they should move on to step 4.


  4. Interactive
    Watch the Battle

    After completing the interactive for this episode students should answer these questions.
    Students should watch the video clips from the Web site and record their responses to the accompanying questions.

  5. For closure, discuss as a class the lab results along with student responses to the video questions. Ask students if they know of other instances in which traditional medicines were found to have a scientific basis. To further stimulate thinking, ask about parallels between traditional Zulu medicines and modern-day usage of performance-enhancing drugs--a possible topic for more research.
Internet Resources

Assessments

  • Participation in class discussion

  • Written responses to video questions

  • Completed lab worksheets
Extensions

  • Research and debate the pros and cons of using steroids and other "performance-enhancing" drugs.

  • Find out about other plants and herbs used in traditional medicines and display the information in a guidebook.

  • Learn more about the different types of chromatography used in chemical analysis.

Correlation to National Science Standards

Standards from http://bob.nap.edu/html/nses/html/6e.html#csc912

CONTENT STANDARD A: As a result of activities in grades 9-12, all students should develop abilities necessary to do scientific inquiry and understandings about scientific inquiry:
    Designing and conducting a scientific investigation requires introduction to the major concepts in the area being investigated, proper equipment, safety precautions, assistance with methodological problems, recommendations for use of technologies, clarification of ideas that guide the inquiry, and scientific knowledge obtained from sources other than the actual investigation.

    Scientists rely on technology to enhance the gathering and manipulation of data. New techniques and tools provide new evidence to guide inquiry and new methods to gather data, thereby contributing to the advance of science. The accuracy and precision of the data, and therefore the quality of the exploration, depends on the technology used.
CONTENT STANDARD B: As a result of their activities in grades 9-12, all students should develop an understanding of structure and properties of matter:
    The physical properties of compounds reflect the nature of the interactions among its molecules. These interactions are determined by the structure of the molecule, including the constituent atoms and the distances and angles between them.
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SECRETS OF THE DEAD is a production of Thirteen/WNET New York. © 2006 Educational Broadcasting Corporation. All rights reserved.