THE EFFECTS OF ACID RAIN ON BEAN GERMINATION AND GROWTH BLOG

STUDENT PEN NAMES:  Littleperm, Evergreen7, Deadtrees, Nitro21

ASPIRE MENTORS: Matt Gilbert  

OBSERVATIONS: Our group is concerned about the health of the planet.  We talked about pollution and global warming and wanted to learn more.  In Fort Nelson we have in-days at school during lunch time because it is too cold, but in China they have in-days when the air is not safe to breathe.  Clearly there is a huge problem. Acid Rain is a problem caused by pollution from factories and vehicles.  We wanted to see the effects of acid rain on seeds and plants. Below are some of the sites we used to research Acid Rain and pH.
QUESTION: How does acid rain affect the germination and growth of green bean seeds?

HYPOTHESIS:  From our research we found out that acid rain has a pH of approximately 5.6.  Therefore we think that some of the bean seeds will be able to germinate with water at a pH level of 5, but will sprout and grow at a slower rate. We believe bean seeds watered with anything under a pH 4 rating will not germinate or grow.

EXPERIMENT:
1. Gather materials. (bean seeds, vinegar, distilled water, pH strips, beakers, ruler, plastic pipettes)
2. Mix 900 millilitres of distilled water and 300 millilitres of vinegar to make your first solution 1200 milliliteres. Use the pH strips to test the pH level (this solution should be about a 3 on the pH scale)
3. Take about 90 milliliters of your initial solution and mix it with 810 millilitres of distilled water. The solutions should all be about 1 level more then the solution before it. Make as many as you need. (This solution should be about a 4 on the pH scale)
If you need to add distilled water to your solution to raise the pH do so)
4. Now repeat step 3 to get your third solution, but remember to start by taking 1/10th of the second solution. (This solution should be about a 5 on the pH scale)
5. Have a separate solution of just distilled water to serve as your control for this experiment.
6. We also were curious to see how plants germinated in tap water since this is what most people in Fort Nelson would be using for watering purposes.  (our tap water had a pH of about 6.7)
7. Now you are ready to move on to germinating the bean seeds.

Creating our different pH solutions. Vinegar was used to lower the pH of distilled water.	Testing the pH of the solution using a pH strip.
Figure 1. Measuring vinegar using a graduated cylinder.	Figure 2. Solutions were tested and retested to determine the pH of each solution.

Set-up: Stage One

1. Count out 50 green beans, 50 Ziplock bags, and 50 paper towels / napkins.
2. Label 10 bags for each pH with the sharpie. (We chose pH 3, pH 4, pH 5, Distilled water (which had a pH of about 5.7) and tap water with a pH of 6.7.
3. Place one green bean in a paper towel  and one napkin in each ziplock bag.
4. Add the correct solution in each bag, using a clean “small” test tube for each solution. The paper towel should be mostly damp, if the solution is collecting at the bottom of the bag, then you have too much of the solution, likewise, if the napkin is too dry, then you have added to little of the solution.
5. Place all the bags in a dark, warm place.
6.  Now every three days, take them out of the bag and measure the length of growth. Record your data on your data sheets.

Set-up: Stage Two
1. Take 5 of your 10 seeds that have germinated and plant them in soil. Use a mixture of germination soil and potting soil.
2. Place the planted seeds in a window.

Experimental Design:
The constants in this study are:
We used the same kind of bean seeds and distilled water
The way we germinated the seeds (the number of paper towels, amount of water, bags, environment)
The way we planted seeds, watered the dirt and leaves, measuring techniques, environment)

The manipulated variable or independent variable was the pH concentration of the water the plants and seeds were watered with.

The responding variable or dependent variable was the root growth while germination and the height or growth of the plant once it was planted in the soil.

DATA:

 

 

 

 

 

 

 

Five of the 10  germinating bean seeds from each pH level  were planted on April 26th. They were watered with the previously prepared pH levels. Pictures taken on April 29th.

Bean Plants - April 29	Bean Plants - April 29 Distilled Water - pH 3	Bean Plants - April 29 Distilled Water - pH 4
Figure 6. All Plants	Figure 7. No Growth - pH 3	Figure 8. No Growth - pH 4

Bean Plants - April 29 Distilled Water - pH 5	Bean Plants - April 29 Distilled Water - pH 5.7	Bean Plants - April 29 Distilled Water - pH 6.5
Figure 9. Signs of two plants growing	Figure 10. Signs of three plants growing	Figure11. Signs of two plants growing

Bean Plants - May 2 Distilled Water - pH 3	Bean Plants - May 2 Distilled Water - pH 4	Bean Plants - May 2 Distilled Water - pH 5
Figure 12. No Growth	Figure 13. Four Plants showed Growth	Figure 14. Four Plants showed Growth

Bean Plants - May 2 Distilled Water - pH 5.7 Germinated Seeds	Bean Plants - May 2 Tap Water - pH 6.5 Germinated Seeds	Bean Plants - May 2 Tap Water - pH 6.5 New Seeds
Figure 15. Four Plants showed Growth	Figure 16. Four Plants showed Growth	Figure 17. No Measurable Growth

[table “7” not found /]

Seeds Germinating With pH3 Water	Seeds Germinating With pH4 Water	Seeds Germinating With pH5 Water
Table 1. Data showing growth of seedling.	Table 2. Data showing growth of seedling.	Table 3. Data showing growth of seedling.

Seeds Germinating With pH5.7 Water	Seeds Germinating With pH6.5 Water	Watering seedlings wrapped in paper towels.
Table 4. Data showing Growth of seedling.	Table 5. Data showing Growth of seedling.	Figure 18. Extreme care was taken to not break roots.

pH 3 Plant Growth Data	pH 4 Plant Growth Data	pH 5 Plant Growth Data
Table 6. Growth from April 26- May 17	Table 7. Growth from April 26- May 17	Table 8. Growth from April 26- May 17

pH5.7 Plant Growth Data	pH6.5-Plant Growth Data	pH6.5 Plant Growth Data with New Seeds
Table 9. Growth from April 26- May 17	Table 10. Growth from April 26- May 17	Table 11. Growth from April 26- May 17

RESULTS:

Bean Germination Average Growth
Table 12. This table shows the average growth of bean seeds germinating in moist paper towels at different pH levels.

Bean Germination Average Growth Graph
Figure 19. This line graph shows the average growth of bean seeds germinating in moist paper towels at different pH levels.

AVERAGE Plant Growth
Table13. Data reflects the average Plant Growth of bean Plants watered with different pH concentrations.

AVERAGE Plant Growth
Figure 20. This graph shows the average Plant Growth of bean Plants watered with different pH concentrations.

CONCLUSION:  

The purpose of our investigation was to determine the effect of acid rain on the germination and growth of green bean seeds.  We hypothesized that  some of the bean seeds would be able to germinate with water at a pH level of 5, but would germinate at a slower rate and would grow at a slower rate. We believe bean seeds watered with anything under pH 4 concentration would not germinate or grow.

GERMINATION:  Our data partially supported our hypothesis.  Although the bean seeds watered with pH 4 and 5 concentration were able to germinate the root growth was at a slightly slower rate. When watered with pH 3 the seeds did not germinate and therefore showed no growth. The seeds watered with a pH of 6.5 had the greatest measured growth. Our graph showed that the seeds watered with pH 4 had the least growth, but the difference in growth for the seeds watered with pH 4, 5, and 5.7  was not significant.
Our data indicates that a highest pH (6.5) produced the greatest growth and the lowest pH (3.0) cause no growth.

PLANT GROWTH:
 In terms of plant growth, once again our data partially supported our hypothesis. The seeds that were watered with pH3 during the germination experiment did not show any growth when planted in soil and watered (with pH3 water).  We were surprised to see that the pH 4,5 and 5.7 grew at a similar rate.  We were also surprised to see that the newly planted seeds caught up with the other already germinated bean seeds. From our research we now realize that the reason that the plants with a low pH grew so well was because the soil they were planted in neutralized the acid affect. Because the soil was new and fresh it probably had a high buffering capacity.

Future Investigations:

If we were to do this investigation again we would make it into two separate experiments:
Experiment 1: Effects of Acid Rain on Seed Germination and, Experiment 2: Effects of Acid Rain on Plant Growth.

We were curious to see how well the germinated seeds would grow in soil…but we should have been more careful in choosing the seeds because, as Matthew mentioned we ended up removing some of the best growing individuals from the germination groups (see table 4) which may have influenced our results.

The plant watered with pH 4 appeared sick.  Notice the leaves are brown and full of small holes.  We would like to suggest that this would be a good investigation for future researchers to  look at more closely.  You could design an experiment to determine the Effects of Acid Rain on healthly plants using a spray bottle to simulate an acid rainfall.

 

 

 

 

GREAT RESOURCES
Acid Rain – National Geographic
This is a great resource. Both Matt and Evergreen7 gives it two thumbs up!
Acid Rain: Chemistry for all.  The Fuse School-Youtube
Learn the basics about Acid Rain by watching this Youtube video.