Lesson 10 – Description:
Modeling Human Impacts on Aquatic Vegetation:
Using Duckweed, students test the effects of various pollutions on aquatic vegetation and soil.
Students will be assigned salts, fertilizer, acids, oil, or debris as a variable test. Lab analysis will
be lesson 14.
Unit Goals:
List and describe the pollution problems associated with the Bay.
Lesson Objectives:
Design an experiment to test the effects of a pollutant on aquatic ecosystems.
Collect and Interpret data to determine impacts of pollutant on aquatic ecosystems.
Setting up you Aquatic Plant Lab
•You will be responsible for setting up, designing, and
carrying out an experiment.
• You will be testing the effects of a particular pollutant on
aquatic plants and/or soil.
•You will be working in groups of _#_ to carry out this
assignment.
Setting up you Aquatic Plant Lab
•Obtain materials from the designated area. You will need:
• duckweed
• 1 - 150ml beaker
• 100 ml Freshwater
• Gloves, Goggles and Aprons (per person)
• Soil ~3oz (if needed)
•Return to your desk with this material.
Setting up you Aquatic Plant Lab
1. Add 100ml of fresh water.
2. Place your duckweed plants in the water. They are
suppose to float on or just under the surface.
You’re initial plant setup is complete.
Setting up you Aquatic Plant Lab
•You will be testing the effects of various pollutions on
aquatic vegetation and soil. Variables include:
• Salts - from industrial use and de-icing road ways
• Fertilizer - Agricultural and Residential use
• Acids – Acid Mine Drains, Acid Rain and other industrial waste products
• Oil – Crude Oil leaks and transportation disasters
• Detergents – soaps and other cleaning agents
• Insecticides and herbicides – Agriculture and residential use
• Ammonia – Food processing waste
• Thermal Pollution – rise or fall in water temp. caused by humans
• Debris – Litter and other trash
Process Requirements
•Each day the group will be responsible for collecting data on
your plant and water conditions.
•Depending on your variable being tested you will follow
different procedures. You will be responsible for designing
this procedure based on the scientific method.
•This should take approximately 5mins at the start of class.
•If a group member isn’t present the rest of the group is still
expected to collect the required data.
Group Variables
•You will now be assigned a variable.
• Salts - from industrial use and de-icing road ways
• Fertilizer - Agricultural and Residential use
• Acids – Acid Mine Drains, Acid Rain and other industrial waste products
• Oil – Crude Oil leaks and transportation disasters
• Detergents – soaps and other cleaning agents
• Insecticides and herbicides – Agriculture and residential use
• Ammonia – Food processing waste
• Thermal Pollution – rise or fall in water temp. caused by humans
• Debris – Litter and other trash
Modeling Human Impacts on Aquatic
Vegetation
•Designing your experiment.
• Use the scientific method to design your experiment.
• While designing, think through what you actions you would do to test
your variable. Keep in mind what your question is and how you can
answer it with quantitative and perhaps some qualitative data.
• You may need equipment such as:
• Graduated cylinders
• Beakers
• pH paper, probes, or other test kits
• Also consider…
Modeling Human Impacts on Aquatic
Vegetation
•Consider:
• The number of test samples or dilutions you will use.
• The number of days and type of data you will collect.
• What will be an indicator for an answer/result to your question.
•Example of procedure & considerations:
• 3 variable dilutions (10% peroxide, 5% peroxide, 1% peroxide)
• 1 control (0% peroxide:100% freshwater)
• 5 duckweed plants in each dilution/control.
• Test for 10 days, record the number of duckweed that are still living.
• An indicator that the duckweed is not longer alive is color change to
white or dark brown.
Lesson 14 – Description:
Analyzing Human Impacts on Aquatic Vegetation:
Students analyze the results from their designed experiment and make connections with those
results to the researched Bay Health Indicators.
Unit Goals:
List and describe the pollution problems associated with the Bay.
Lesson Objectives:
Analyze data to determine the effects of various pollutants on aquatic plants and soil
Infer the impacts and relationship of tested variables to researched Chesapeake Bay Health indicators.
Final data collection and Analyzing Results
•Move into groups and begin final data collection.
•DO NOT apply your variable today!
•Once you collect your data, compare you data with group members to
ensure accurate recordings and complete information.
•When finished raise your hand for permission to move on.
Final data collection and Analyzing Results
•All groups should now be finished and have received permission
to work on the “Analysis” portion of the lab handout.
•You will need to test the control in the same manner you have
your variables throughout this lab.
• Be careful not to damage or disrupt the control so that it affects
other groups data collection.
•Remember to add your results to the class data chart.
•Once you have all your data shared complete the comparison
questions.