IOWA 4-9 SCIENCE PROJECT

TEACHER GUIDE for: Dead Guppies Don Knudsen, Robin Madole,
Ron Pethoud and Julie Render
edited by Steve Bartlett
Ecology.593 Grades 5-9

CONCEPT OBJECTIVE:

The student will investigate if water from an apparently
polluted pond can support fish life.


PROCESS OBJECTIVES:

The student will design an experiment and use skills which
include observing, recording and predicting.


TEACHER NOTES:

Collect samples from your suspected site of polluted water
and other sources of your choice. Possibilities include a
local river, tap water, well water, etc. If city water is
used, it will need to be dechlorinated by adding chemicals
or by allowing it to stand uncovered overnight. Each bottle
should contain only one fish and one branch of elodea.
(This is an aquatic plant which can be purchased at a
pet store.) After placing fish and elodea in the bottles,
screw the lid on. Do not place the bottles in direct
sunlight, as it may have a detrimental effect on your fish.
However, the fish and plants do need to have some light.
You may choose to add a small snail to keep the bottle
clean. This activity may be a follow-up to a litter pick-up
or a nature walk.


MATERIALS:

For each group you will need:
three clear 2-liter bottles (with lids) per water source
one branch of elodea per bottle
one guppy per bottle

Also needed per class:
one small fish net
fish food

EXPLORATION:

Scenario:
A group of students were picking up litter on the nature
trail, when they noticed a small creek which was covered
with scum. They wondered whether the water was polluted and
decided to conduct an experiment to find out whether a fish
could live in that water. They decided to test the water in
their classroom. They needed to compare the creek water
with water from other sources and decided that the simplest
way to do this was to set up several 2-liter pop bottle
aquaria. They used three bottles from each water source to
rule out the effects of chance, such as having one sick
fish. A branch of elodea was added to provide oxygen.


CONCEPT DEVELOPMENT:

Students will determine by discussion what factors support
fish life in a fresh water community.
The discussion should include city tap water being used as a
control (after dechlorination). Students will work under
the assumption that if all of the guppies in one water
source die, that indicates that the water will not support
fish life. Students will chart and graph the results of the
experiment, using the water sources as the MV (Manipulated
Variable) and the life span in days as the RV (Resultant
Variable).


APPLICATION:

Activities might be designed to answer these questions:
What would happen if you did not dechlorinate the city
water? What would happen if several guppies were put in a
single bottle? What would happen if only plant life
(elodea) were put in the bottle? What would happen if
elodea was not in the bottle? How could you purify these
water samples to make them fit for human drinking water?

Other related activities:

1. Students may examine each of the water samples with a
microscope and try to identify any organisms or substances
found. They should draw their findings in their journals.

2. Students may test the water samples for various chemicals
(chlorine, nitrates, etc.).

3. A natural follow-up for this cycle would be Foul Water
(Ecology.89#).

4. Another cycle that could be used after this is What's in
the Water (Life.67#).

5. Collect rain water in a clean bucket. Using the same
materials and procedures as above, test the life supporting
qualities of rain water.

STUDENT DATA SHEET



L
|________________________________________
I 4 |
V
|________________________________________
E 3 |

|________________________________________
F 2 |
I
|________________________________________
S 1 |
H
|________________________________________
RIVER | TAP | STREAM | OTHER |