IOWA 4-9 SCIENCE PROJECT

TEACHER GUIDE for: Detergents and Plant Growth Charmaine Fox
Edited By Lowell Wiele
ECOLOGY.781 Grades 6-9

CONCEPT OBJECTIVE:
The concept developed examines the effects of detergents and
fertilizers on the growth of algae and its relationship to the
eutrophication process.

PROCESS OBJECTIVE:
The thinking skills developed in this cycle are observation,
inferring, experimenting, measuring, and recording.

TEACHER BACKGROUND:
Eutrophication is caused by pollution from organic matter,
detergents, and fertilizers. Eutrophication is a change in water
in which the amount of oxygen levels are lowered, causing many
fish and other animals in the water to die and algae to grow in
great numbers. The oxygen levels are lower because the
phosphates cause rapid plant growth and when these plants die and
decompose they use up the dissolved oxygen in the water.

MATERIALS:
Each group of two will need three quart jars, distilled water,
laundry detergent, lawn fertilizer, a teaspoon, pond water, and a
graduated cylinder.

EXPLORATION:
The teacher initiates the exploration by leading a class
discussion about phosphates and their affect on our water supply.
Include the idea that laundry detergents often contain
phosphates. The class discussion should lead to which detergents
are used in the student's home. The teacher should instruct the
students to design an experiment to test which detergents contain
the harmful phosphates. Students can be lead at the beginning of
the experiment to seek specific answers as to what happens if a
specific detergent does contain phosphates, and what will happen
to the water and to organisms found in the water?
The teacher should now provide each group of students with all of
the above materials except for the laundry detergent. Have one
person from each group bring a teaspoon of detergent from their
home, this way the class can also determine if different
detergents affect our environment differently.
Procedure
1. Label one jar A, another B, and the other C.
2. Fill each jar within a couple centimeters from the top.
3. Add a half teaspoon of fertilizer to jar A.
4. Add a half teaspoon of detergent to jar B.
5. Add nothing to jar C.
6. Measure 5 ml of pond water and add it to each of the
three containers.
After the two weeks have passed the students will observe the
three containers and record their observations. After allowing
some time for observation help the students by asking them the
following questions.
. Did more algae grow in some jars than in others?
. What might be the cause of some jars containing more
algae than others?
. Did different detergents have different affects on the
growth of algae than others?

CONCEPT DEVELOPMENT:
When the students have had sufficient time to record their
observations have the students share their data with the rest of
the class. During the class discussion the students should be
able to show evidence of eutrophication.

APPLICATION:
1. Students should investigate the different types of detergents
and chart their results. Show which detergents do not contain
phosphates and will not cause eutrophication and which detergents
contain high levels of phosphates.
2. Have students check labels on detergents to determine which
detergents are safe to our environment.
3. The students may call toll free phone numbers found on the
detergent boxes to find answers to any question about the
detergents they may have.
. Why do some detergents contain phosphates and others do
not?
. Why do some companies make their detergents that they sell
in Iowa contain phosphates, but when they sell it in other
states it does not contain phosphates?
4. Students may write their senators to find out what the law is
in Iowa regarding phosphates and the reason we have the law that
we do on the books.
5. Students should investigate how eutrophication affects the
environment, and see if anyone can find eutrophication taking
place in their community.
6. Conduct a student survey to indicate how many families use
phosphate based detergents.
7. Students may check the various detergents at the grocery store
to determine the percent of environment ally safe detergents being
sold. Store employees can tell the student which detergents are
their biggest sellers.

DETERGENT / PLANT GROWTH

STUDENT ACTIVITY SHEET



| | | OBSERVATIONS |
| JAR | CONTENTS | AFTER TWO WEEKS |
| | | |
| | | |
| A | | |
| | | |
| | | |
| B | | |
| | | |
| | | |
| C | | |
| | | |


1. Which jar contained the most algae growth?


2. Why might that jar contain the most algae?


3. After checking with other groups in the class do you think
that different detergents affect the growth differently? Why?


4. What ingredient is found in some detergents and not in others
that may be responsible for eutrophication?

EVALUATION:
The teacher's observations of the student toward attaining the
process and concept objectives during the learning cycle is a
valid evaluation tool.