Teacher's Guide
Effects of Water Pollution on Plants
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Overview:
Students will perform an experiment in which they will observe how water
pollution is absorbed into plants.
Background Information
Only pure water is evaporated, while other substances are left behind.
As a result these impurities become part of the water system. All water
eventually flows to the oceans. In Fremont, water flows into the San Francisco
Bay through a series of creeks and sloughs. Waters running off the west
side of the Fremont section of the Diablo Range fill creeks all along the
mountain side. These stream waters are joined by waters flowing through
city storm drains as well as water run-off from the various farmlands around
Fremont. Run-off water may drop into Tyson Lagoon or Lake Elizabeth along
the way. The streams enter the bay through the Alameda Flood Channel, Newark
Slough, Plummer Creek, Mowry Slough and Mud Slough.
Pollution anywhere along this pathway will find its way into the bay.
Plants, animals, and microorganisms are all affected by pollution found
in the creeks and ponds along the pathway to the bay.
Student Activity:
Below is information that will help you prepare and conduct the experiment
on water pollution. Read all the information before beginning the experiment
with your class. The Student
Worksheet should be printed and copied to provide each student with
their own copy of the lab.
Purpose: To see if pollution in water will affect plants.
Hypothesis:
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Explain that a hypothesis is a best guess of what they think will happen
during an experiment. A good hypothesis not only states what they think
will happen, but also why they think it will happen.
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Read through how to perform the experiment with the students.
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Ask the students to decide what they think will happen to the leaves and
veins of the celery.
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Ask them to discuss what they think will happen and then write their hypothesis
on their lab sheet.
Materials: Have these available for the students the day of the
experiment.
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Three stalks of fresh celery per group
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Three Mason jars
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Water
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Red and blue food coloring
Procedure:
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Fill each Mason jar half full with water.
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In one jar add four drops of red food coloring.
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In one jar add four drops of blue food coloring.
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In one jar do not add any food coloring. This is the control sample. You
will compare the other two celery stalks to the one left in the plain water.
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Cut about 1 inch of the end of the celery off.
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Place one stalk into each of the three jars of water.
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For one week, observe the leaves and stalk veins of the celery every day.
You are looking for a change in coloring the leaves and veins.* In order
to see the veins, you may need to break off a piece of the stem and look
at a cross-section of the stem.
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Record your results by filling in the chart.
Observations:
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Day 2 |
Day 3 |
Day 4 |
Day 5 |
Day 6 |
Day 7 |
Plain Water
Leaves |
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Plain Water
Veins |
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Red Water
Leaves |
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Red Water
Veins |
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Blue Water
Leaves |
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Blue Water
Veins |
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Conclusion:
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Ask the students to discuss what they observed.
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Did they notice any change in color of the plant's leaves or veins?
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Were all the plants equally healthy?
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You may either ask the students to write their conclusion at this point
by answering these questions, or you can have the discussion prompted by
the analysis and then have them write their conclusions.
Analysis:
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Remind the students that plants pull water up to their leaves through their
veins. If the water is polluted, the pollution will move up through the
plant with the water. As a result the plant will be polluted. Anything
eating the plant will ingest the pollution into their bodies.
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In this experiment the pollution was obvious, it had color to it. Many
forms of pollution are odorless and colorless. As a result, you cannot
tell they are polluted by looking at them. All water must be kept clean
so that pollution will not become part of the plants and animals that live
in and near the waters.
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