IOWA 4-9 SCIENCE PROJECT
TEACHERS GUIDE for: EFFECTS OF ACID RAIN Charmaine Fox
edited by Mike Rathe
ECOLOGY.795 Grades 7-9
CONCEPT OBJECTIVE:
The student will be able to identify effects of acid rain on living organisms
and list solutions to the problem
PROCESS OBJECTIVES:
To develop the students' observation skills.
To develop the students' inferring skills.
To develop the students' ability to control variables.
To improve the students' measuring and recording skills.
TEACHER INFORMATION:
A 10% sulfuric acid solution can be prepared by mixing 5 ml of concentrated
sulfuric acid to 90 ml of distilled water. The pond water will have to collected
ahead of time and boiled.
MATERIALS NEEDED
(for each group of two students) 4 - 250 ml beakers or containers of equal
size, masking tape, wide range pH paper, pond water that has been boiled,
organisms such as Daphnia, hand lens, grease pencil, goggles, graph paper,
and dropper bottles with 10% sulfuric acid .
STUDENT BACKGROUND:
It is assumed that the student understands how to measure the pH of a solution
with pH paper and what that value represents . The student needs to know
the correct procedure in which to handle acids. The student also needs to
have a general understanding of the dependency of predator animals on the
smaller animals of an ecosystem.
EXPLORATORY ACTIVITY:
Create a scenario of a small lake in the Adirondak Mountains in upstate
New York. The winds carry acid laden smoke from factories in Pennsylvania,
and residents from lake Watahatchee are concerned about the lakes decreasing
level of pH. Lake Watahatchee's pH has dropped by from a pH of 7 to 5 over
the last ten years. They are wondering if this pH change is going to effect
their tourism for this great fishing area. This area has produced the largest
fish caught in the state for the past four years and fishing tourism is
the largest industry in the area. Your school is in this area and you have
decided to do an experiment to see how low pH of the lake could go before
it affects the species of the lake. You will design an experiment as a group
to determine the pH which will effect the small organisms of the lake .
Your teacher has suggested that the primary animal at the base of the food
chain in lake Watahatchee is daphnia, and has brought samples to the room
for you to observe . You understand that lowering of animals at the lower
end the food chain will effect the number of surviving larger species.
Discuss the problems of acid rain and have the students discuss possible
causes and responses of the lake. Ask the students how they could determine
whether the pH change was affecting the lake and what experiment they could
do to determine when that change would take place.
Have your students develop an experiment which would address the following
problem :
How low can pH of the water of lake Watahatchee become before the Daphnia
die?
Your class' experimental design could be something like the following:
MATERIALS NEEDED
(for each group of two students) 4 - 250 ml beakers or containers of equal
size, masking tape, wide range pH paper, pond water that has been boiled,
organisms such as Daphnia, hand lens, grease pencil, goggles, graph paper,
and dropper bottles with 10% sulfuric acid .
You will make 3 different solutions of acid water, pH of about 3, 4, and
5. Use the pond water to fill all 4 containers to the same level. One container
with only pond water that has been boiled will be the control. You will
add sulfuric acid drop by drop to the other 3 beakers. Using Ph paper test
the water for the pH. Make sure you label the container with the pH level.
Add 2 ml of Daphnia to each of the four containers. After a few minutes,
take an eye dropper and mark it about halfway up the glass tube with a grease
pencil. Fill the dropper to the line with water from the control beaker
and empty it into a shallow dish. Using a hand lens, count the number of
Daphnia you find that appear to be alive. After observing the control, count
the number of organisms in the other three jars. Leave the beakers in an
undisturbed place and make observations and sample counts each day for 3
days.
CONCEPT DEVELOPMENT:
Distribute the materials, instruct the students to follow the following
directions:
To help the students understand the data collected ask them the following
questions:
"Which sample had the most organisms that were living?"
"Did the samples change over time?"
"Can you tell if a sample is acidic by looking at it?"
This is one way that the exploration activity could take place. You may
find that you would rather give the students the materials and challenge
them to create an experiment to determine the effects of acid rain on organisms.
After the students have collected their data have them graph the information,
graph the number of organisms versus the day for each pH.
After the activity a class discussion may emphasize the following points.
"What pH is the best living conditions of Daphnia?"
"What effect might the pH of lakes have on other living organisms?"
"What type of curve was produced by the graph?"
"When does the graph predict the pH of Lake Watchatchee will become
dangerous for daphnia?"
APPLICATION ACTIVITY:
1. The students may write a position paper about what they feel would be
a good solution, using the concept they developed. they must consider how
their solution is going to affect the area economically and how it will
effect the environment.
2. Divide the students into to groups and have them debate acid rain. One
group should represent the utility companies and the other group should
be environmentlists.
3. Design another experiment to investigate the effect of acid rain on plant
and animal life. Carry out the experiment, collect data, summarize the conclusions
in a written paper or a report back to the rest of the class.
STUDENT DATA SHEET
NUMBER OF SURVIVING ORGANISMS
| DAY | CONTROL |BEAKER|pH |BEAKER|pH |BEAKER|pH |
|______|________|__1___|__|__2___|_ _|__3___|___|
| 1 | | | | | | | |
| 2 | | | | | | | |
| 3 | | | | | | | |