Death of a Pond Lab

Death of a Pond

By: Tanya Sharma

09/10/15

Lab Partners: Rebecca Hill, Marcos L. Gonzales & Alex Cone

Ms. Farmer

Tuscarora High School

Purpose: The purpose of this lab was to determine which source a pond receives runoff from that causes the duckweed to grow quicker and faster.

Introduction: A large pond that once was a spot for people to swim and fish is now being invaded by duckweed. The pond receives runoff from three sources including a vegetable farm whose wastewater contains fertilizer, a bakery whose wastewater contains sugar and a factory whose wastewater contains an acidic substance. In order to determine what is causing the downfall of this pond, we must test which runoff is causing the duckweed to grow.

Hypothesis: If runoff containing sugar, acid and fertilizer go into the pond, then duckweed will grow rapidly in the pond due to the fertilizer runoff.

Materials:

• Small Plastic Cups
• Googles
• 25 mL Acidic Water
• 125 mL Pond water
• Graduated Cylinder
• Duckweed
• 25 mL Sugar Water
• 25 mL Fertilizer Water
• Light Source                                          
• Paper Towels
• Pencil
• Tape (labeling)

Procedure:

1. Setup 4 small plastics cups with same amount of water (each one with 25 mL).
2. Label each cup, according to their solutions.
3. Fill one cup with vinegar water (25 mL).
4. Fill another cup with sugar water (25 mL),
5. Fill an additional cup with pond water (50 mL)
6. Fill the last cup with liquid fertilizer (25 mL).  
7. Collect 8 duckweed plants per cup and place them inside each cup.
8. All of the cups will be receiving the same amount of light each day.
9. After placing the plants, observe and record for 4 days the duckweed growth.

10. Collect the data in the table.

Data Table:                       

Duckweed Growth

Conclusion:

In conclusion, the three runoffs of sugar, acidic and fertilizer water did not affect the deterioration of the pond. According to the data collected the duckweed in the sugar water container started to die decreasing from nine duckweed on day two, to three duckweed at the end of the experiment. The acidic water displayed almost the same results by the end of day four all the duckweed in the pond were dead. In the fertilizer water, the duckweed grew by one, on day two but after day two the amount of duckweed deteriorated to six on day four. This shows that the runoff going into the pond doesn’t have a direct correlation with the sudden growth of duckweed.