Lab: The Effect of Simulated Acid Rain on Plant Growth and Development
Background: Available on the Wiki.
Pre-lab questions:
1. What is 'acid rain' (acid deposition)?
2. What conditions lead to acid deposition?
3. Explain some of the man-made causes of acid deposition.
4.Discuss some natural causes of acid deposition.
5. What are some affects of acid deposition on local ecosystems (plant-life, animal-life, etc.)?
6. How much stronger would rain with a pH of 2 be stronger than rain with a pH of 4?
7. What are some essential materials that plants need to grow?
8. How might the acid in the water you are using affect your soil quality?
9. You will have one plant that you will water with tap water. Why?
10. Identify your controls, independent, and dependent variables in this experiment.
Introduction: In this experiment, you will be using simulated acid rain made from sulfuric acid
to test the effect on seed growth and development. You will be growing radish seeds, because
they are easy to grow and develop quickly. The beans were soaked in water for 72 hours to
promote germination. You will have three plants. You will water one with a strong acid (pH 23), one with a weak acid (pH 4-5) and one with tap water. Over the next few weeks, you will
track and measure growth in all three plants, as well as any physical changes (changing color,
wilting, etc). At the end of this experiment, you will write a lab report to display your findings.
Materials:
Goggles
gloves
Styrofoam cups (3)
Potting soil
Radish seeds (15)
Dissecting probe
Graduated cylinder
NOVA datalogger and pH meter
sharpie
tap water
weak acid rain solution
strong acid rain solution
ruler
paper towels
Procedure:
1. Put on your gloves and eyewear.
2. Label your cups 'tap water', 'weak acid', and 'strong acid' along with your names and block
with the sharpie.
3. With the dissecting probe, poke three holes in the bottom of each of your Styrofoam cups
for drainage. Don't make the holes too big. Be careful! The edge of the probe is sharp!
4. Add soil to your cup, about a half inch below the rim.
5. Place five seeds in each cup, and cover them with a THIN layer of soil.
6. Obtain 50 ml of TAP water in your graduated cylinder. Measure the pH.
7. Over the sink, add the tap water to the cup marked 'tap water' allow to drain. After it
drains, place the cup on a folded paper towel.
8. Obtain 50 ml of WEAK ACID in your graduated cylinder. Measure the pH. It should be
between 4 and 5. If not, contact me. Careful! This sulfuric acid is 'weak' but still strong
enough to damage skin and clothes, and irritate eyes and nose. Do not inhale, wear
your gloves and eyewear!
9. Over the sink, add the weak acid solution to the cup marked 'weak acid' allow to drain.
After it drains, place the cup on a folded paper towel.
10. Obtain 50 ml of the STRONG acid solution. Measure the pH. It should be between 2 and 3.
If not, contact me. Careful! This sulfuric acid is very strong!!! IT can damage your skin,
eyes, and clothes. Wear your eyewear and gloves!
11. Over the sink, add the strong acid solution to your cup labeled 'strong acid'. Allow to
drain. Sit on a paper towel.
12. Place the cups in a designated area that receives plenty of sunshine designated by the
teacher.
13. Wash your glassware and clean up your station. Rinse off your pH probe and place in fresh
tap water.
Important notes:
 The acid rain flasks are marked 'A' and 'B'. Always get your solution from the same flask.
 Order is important. Always water the tap water, then the weak acid, then the strong
acid to avoid mixing acid in your tap water or bringing down the pH of your weak acid.
 Always wear gloves and eyewear when handling the acid rain solution or the plants
that have been watered with acid rain.
 You will be creating a line graph of the heights of the plants over the next few weeks.
 One person from your group will handle the acid plants, to cut down on your gloves
 Measure your plants every day that you are in class.
 Water your plants at least three times a week.
Data
Ph of tap water: __________ pH of weak acid: __________ pH of strong acid: _________
Day & Date
1
_____
_____
______
Tap water
# plants
Height (mm)
General
appearance
# plants
Height (mm)
General
appearance
# plants
Height (mm)
General
appearance
# plants
Height (mm)
General
appearance
# plants
Height (mm)
General
appearance
# plants
Height (mm)
General
appearance
# plants
Height (mm)
General
appearance
# plants
Height (mm)
General
appearance
# plants
Height (mm)
General
appearance
Weak acid
Strong acid
Watered? y/n