The Copper Basin Problem: Student Section Investigation 4

How Does Acid Rain Affect the Germination of Seeds?
(Coordinates with Teacher Lesson 5)

Acid rain is a big problem in the Copper Basin area. The local residents reported damage to the leaves of trees after periods of rainfall or fog. In this investigation, we will determine the effects of acidic conditions on plants. Because of the need for a controlled environment in the lab, we will examine the effect of pH on the germination of seeds.

Problem:

How does pH affect the germination of seeds?

Materials:

• petri dishes
• wax pencil
• paper towel disks
• scissors
• ruler
• water solutions: pH 2, 3, 4, 5, 6, & 7 (simulated rainwater)
• seeds

Procedure:

1. Construct a table on which to record your observations.
2. Predict what will happen to seeds grown in solutions of differing pH. Record your predictions.
3. Cut disks of paper towel to fit the bottom of a petri dish. Place 4 paper towel disks in the bottom of each petri dish.
4. Dampen the disks with one of the pH solutions. Label the lid of the petri dish with this pH. Measure the lengths of the 5 seeds that are to be placed in this dish and record these measurements. Place the seeds in the petri dish and cover.
5. Repeat this procedure using the other pH solutions. There will be a total of 6 dishes.
6. Each day, remove the lids of the dishes. Measure the seeds and record your observations on a data table. If necessary, add appropriate solutions to keep the seeds moist.
7. On the last day share your results with other groups.
8. Construct a line graph of the averaged results.