Lesson Plan #:AELP-BIO0014
An AskERIC Lesson Plan
Submitted by: Jess Lang
Endorsed by: Dr. Don Descy
Date: February 1997
Students will construct an aquatic ecosystem in
a two-liter pop bottle. The stock organisms will be: water plants, snails,
and fish. Students will record data concerning the observations they make
over a four-week period.
Grade Level: Intermediate
Students will exercise important early scientific skills,
like observing, measuring, classifying, communicating data, inferring,
- Students will, in groups of four, construct aquatic habitats in pop
- Students will create charts to record data from observations.
- Students will observe the habitats over a period of four weeks, and
record what they see—changes in population, plant growth, water
quality, and animal growth.
- At the end of the observation period, students will graph their data.
- Students will write explanations for what they observe. Also, questions
will be posed with specific questions, such as: “What would happen
to your plant population if you added more snails?” or “What
environmental factors do you think influenced the growth of your
fish/snails/plants?” or “What do you think would happen
if the fish population doubled? Quadrupled?”
- 2 two-liter pop bottles for each group
- water source
- light source
- water snails
- graph paper
- Cut The top off one bottle, at the shoulder (where it tapers). Cut
the base off another bottle and score it with holes. This is the cover.
- Fill bottom of bottle with sand, two inches deep.
- Add water—slowly, to minimize sand displacement—and then
root three ten-centimeter elodea stalks firmly in the sand. Sprinkle
a small amount of duckweed onto the water's surface.
- Let the aquaria stand overnight to let the sand settle and to allow
chlorine from water to dissipate (if tapwater is used).
- Add two guppies and two snails.
Over a four-week period, have the students record daily observations
in journals. Suggest certain things for them to be watching for, like plant
growth or population changes. Ask for quantitative measurements (exactly
how many? exactly what size? how many days?) as well as qualitative (what
color? what shape? slow or quick movement?).
During the observation period, have students research pond ecology and
the organisms involved in the project.
At the end of the observation period, have the students graph the
information they’ve obtained through observation. At this time,
they should write hypotheses to explain some of the things they’ve
Are the aquaria appropriately stocked? Have they been well-maintained?
Are observations recorded at regular intervals? Are graphs drawn correctly?
Are hypotheses based in fact?
Information about bottle aquaria taken from Bottle
Biology, copyright 1993,
by the Bottle Biology Project, University
of Wisconsin, Madison.
Let us know what you think! E-mail our webmaster