Acid Rain and Daphnia Science Fair Projects

PROCEDURES

I. Setting Up
1) Label each side of two petri dishes, “pH 7. 5. ” This is your control group.
2) Label each side of two more petri dishes, “pH 6. 5. ”
3) Label each side of two petri dishes, “pH 5. 5. ”
4) Label each side of the last two petri dishes, “pH 4. 5. ”
5) Add 8 daphnia to each petri dish by using an eyedropper.

II. Conducting the Experiment
1) Pour 5 ml of the 7. 5 PH solution into each side of the two petri dishes labeled, “pH 7. 5. ”
2) Using a jeweler’s loupe, check the daphnia’s heartbeat. Count the number of living daphnia and record that number on your data sheet.
3) Pour 5 ml of the 6. 5 PH solution into each side of the two petri dishes labeled, “pH 6. 5” using a graduated cylinder.
4) Repeat step 2.
5) Pour 5 ml of the 5. 5 PH solution into each side of the two petri dishes labeled, “pH 5. 5” using a graduated cylinder.
6) Repeat step 2.
7) Pour 5 ml of the 4. 5 PH solution into each side of the two petri dishes labeled, “pH 5. 0” using a graduated cylinder.
8) Repeat step 2.
9) Wait 15 minutes.
10) Repeat step 2 for each petri dish.
11) Repeat steps 9 and 10 until it has been an hour since the first time you checked.
12) Wait an hour and repeat steps 9 and 10.
13) Wait two more hours.
14) Repeat steps 9 and 10.
15) Wait 4 more hours.
16) Repeat steps 9 and 10.

RESULTS

The first original purpose of this experiment was to determine the effect of acid rain exposure time on the survival rate of daphnia.

The second original purpose of this experiment was to determine the effect of different levels of pH on the survival rate of daphnia.

The results of the experiment were that the survival rate of the daphnia decreased as the exposure time increased, but only in the group that was the most acidic. The 7. 5, 6. 5, and 5. 5 acids did not decrease the survival rate of the daphnia exposed to them. After the total 8 hours, out of eight, the average number of surviving daphnia in the 7. 5 (control) group was 8, 8 in the 6. 5 group, 8 in the 5. 5 group, and 6 in the 4. 5 group.

CONCLUSION

My first hypothesis was that the daphnia survival rate would decrease as exposure time to acid rain increased.

My second hypothesis was that the survival rate would decrease as the pH levels got more acidic.

The results indicate that these hypotheses should be accepted. After one hour, one of the daphnia was dead and more died as time passed. More of the daphnia died in the pH 4. 5 group, which was the most acidic.

Because of the results of this experiment, I wonder if other pollutants such as antifreeze or oil would affect daphnia. Also, I wonder if the temperature of the liquid would affect the results.

If I were to conduct this project again I would use more daphnia and check the number of surviving daphnia over 24 hours instead of eight. 3rd party contributor