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The Mystery of the Disappearing Lake

(Impact of Invasive Phragmites on Wetland Hydrology)

Grade Level: 6-8

Time Frame: 40-45 minutes

Introduction to Lesson: 

This lesson provides students with the opportunity to use what they’ve learned about transpiration to solve a mystery about why wetlands often go dry when the invasive form of Phragmites starts to grow there.  The teacher will guide students through a PowerPoint in order to have them solve this mystery by relating it to the high transpiration rates in invasive Phragmites.

New Jersey Core Curriculum Content Standards 

STANDARD 5.1 (Scientific Processes) All students will develop problem-solving, decision-making and inquiry skills, reflected by formulating usable questions and hypotheses, planning experiments, conducting systematic observations, interpreting and analyzing data, drawing conclusions, and communicating results.

A. Habits of Mind

  1. Evaluate the strengths and weaknesses of data, claims, and arguments.
  2. Communicate experimental findings to others.
  3. Recognize that the results of scientific investigations are seldom exactly the same and that replication is often necessary.
  4. Recognize that curiosity, skepticism, open-mindedness, and honesty are attributes of scientists.

B. Inquiry and Problem Solving

  1. Identify questions and make predictions that can be addressed by conducting investigations.
  2. Design and conduct investigations incorporating the use of a control.
  3. Collect, organize, and interpret the data that result from experiments.

C. Safety

  1. Know when and how to use appropriate safety equipment with all classroom materials.
  2. Understand and practice safety procedures for conducting science investigations.

STANDARD 5.8 (Earth Science) All students will gain an understanding of the structure, dynamics, and geophysical systems of the earth.

Atmosphere and Water

·          Describe and illustrate the water cycle.

STANDARD 5.10 (Environmental Studies) All students will develop an understanding of the environment as a system of interdependent components affected by human activity and natural phenomena.

Human Interactions and Impact                                                                                        


Describe the effect of human activities on various ecosystems


Evaluate the impact of personal activities on the local environment.

STANDARD 9.2 (Consumer, Family, and Life Skills) All students will demonstrate critical life skills in order to be functional members of society.

Critical Thinking

bulletCommunicate, analyze data, apply technology, and problem solve.

ObjectivesAfter completing this activity students will be able to


Describe transpiration and some of the factors that affect the rates of this process


Students will be able to describe how transpiration from Phragmites affects a wetland


Students will be able to explain some of the reasons why invasive Phragmites has a particularly strong effect on the hydrology of a wetland

Materials and Resources:


PowerPoint  ("The Mystery of the Disappearing Lake") (pdf format)


Teacher's Guide to PowerPoint  ("The Mystery of the Disappearing Lake")


Student worksheet (to help keep students on task during presentation).

Anticipatory Set:

Complete the day 2 portion of the transpiration lab and discuss the questions posed at the end of that exercise.

Sequence Instruction:

Teacher will guide the students through the “Mystery of the Disappearing Lake” PowerPoint. Students will discuss why Phragmites dries up the wetlands.

Accommodations and Modification:

[None should be needed]


Have students write 3 things they found interesting about today's class, 2 new things that they learned and one thing they still have a question about.

Homework / Extension Activity

Have students write a brief story entitled "The Mystery of the Disappearing Lake".  They can be as creative as they like, but their story should answer the following questions. 

bullet What was the mystery? 
bullet What changes were seen as the mystery unfolded?
bullet What clues were there as to what caused the observed changes? 
bullet What were the characters of the “villain” that caused that “villain” to have the effect that it did?
bullet What if anything do you think could have been done to prevent this mystery from having taken place in the first place?


TEACHER FEEDBACK REQUEST:  We are always to working to improve these lesson plans. If you use this lesson plan, we'd love to hear from you with your thoughts, comments and suggestions for future improvements.  Please take the time to fill in our survey at .  Thanks!


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© 2009.  Jodi Sisk (Author), Louise Wootton and Claire Gallagher (Editors)

 Although the information in this document has been funded wholly or in part by the United States Environmental Protection Agency under assistance agreement NE97262206  to Georgian Court   University, it has not gone through the Agency's publications review process and, therefore, may not necessarily reflect the views of the Agency and no official endorsement should be inferred.

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