IOWA 4-9 SCIENCE PROJECT

Teacher Guide for: Pollution of an Aquatic Ecosystem Steve Bartlett
ECOLOGY.792 Grades 7-9

CONCEPT OBJECTIVE:

This learning cycle should be used with the Guppies,
Cycles, and Ecosystems learning cycle but it could be used
independently in another unit. In this cycle, students are
asked to design an experiment to investigate the pollution
of an aquatic ecosystem like a pond or lake.


PROCESS OBJECTIVE:

Thinking skills developed in this cycle are predicting,
investigating, designing, recording and reporting.


TEACHER BACKGROUND:

This cycle was written to supplement the Guppies, Cycles,
and Ecosystems learning cycle. A pollutant can be any
material such as a gas, a solid, or a liquid that is somehow
released into the environment by way of air or water. The
quality of the air we breathe and the water we drink and use
is directly affected by pollutants. Animals and plants may
be directly or indirectly affected by pollutants. Some
living things may show an immediate reaction to a pollutant
or they may not show any ill effects until days, weeks,
months or years later. Basically the students set up an
aquatic ecosystem similar to the one they used for their
guppy/cycles/ecosystem experiment. They then decide on a
type of pollutant to introduce to the system and design an
experiment to test the effect of this pollutant on the
aquatic system. They should have their plan approved by
their instructor and then carry out the investigation
collecting and recording data. At the end of the
investigation, a conclusion should be made based on their
results and they may present their findings to the rest of
the class.


EXPLORATION:

As a class, have the students discuss what they feel the
definition of a pollutant is. These may be listed on the
board and a class definition of a pollutant may be decided
upon.
Have the students in small groups or as a class brainstorm a
list of pollutants that might affect an aquatic ecosystem
like a freshwater pond or lake. After the list has been
compiled, have
the students individually or in groups list on paper what
they believe would be the effects of each individual
pollutant on plant and animal life in the water. Some
possible things to try are pesticides (insect spray),
fertilizer (liquid plant fertilizer), garbage, metals, acid
rain ( mix mild concentrations of sulfuric acid), thermal
(add different temperatures of hot water), etc.


CONCEPT DEVELOPMENT:

The students should design an experiment to test the effects
of their pollutant on their ecosystem. The plan should be
submitted to the teacher for final approval. The following
guidelines may be useful to help the students plan their
investigation:
TITLE OR PURPOSE OF INVESTIGATION ( write a brief summary of
what you plan to investigate). State your problem in the
form of a researchable question. Include the name of the
pollutant you will use. What do you think its effect will
be?

MATERIALS: Make a list of all the materials that you will
need.

PROCEDURE:

List step by step what you will do to set up and carry out
your investigation.

DATA AND OBSERVATIONS: What data will you keep track of? How
will you do it? How often? Make a data table to keep track
of the information.


APPLICATION:

The students should construct their aquatic ecosystems or
they may use their previous aquatic ecosystem if it is still
functioning. They should carry out their pollution
experiment for a period of time to be determined, collect
data and be able to give a presentation explaining the
results of their work.
QUESTIONS:
1. Did the results of your experiment turn out the way you
thought?

2. If you did this experiment again what would you change in
the experiment?

3. Do you think the results of your experiment were
realistic comparing it to a real pond or lake ecosystem?