Unit 7 Lab Report with Sample Data
Title: Investigating the Effect of Light Intensity on the Rate of Photosynthesis in Elodea
Introduction:
Photosynthesis is the process by which green plants convert light energy into chemical energy in the form of glucose. Light intensity is one of the controlling factors that affect the rate of photosynthesis. The purpose of this experiment is to investigate how varying light intensity affects the rate of photosynthesis in Elodea, an aquatic plant commonly used in experiments.
Hypothesis:
As light intensity increases, the rate of photosynthesis in Elodea will also increase.
Materials:
- Elodea plant
- Lamp
- Light meter
- Beaker
- Stopwatch
- Water
- Sodium hydrogen carbonate (to provide carbon dioxide)
Procedure:
1. Set up a workspace near a power source and place the lamp at a specific distance from the Elodea plant.
2. Measure and record the initial distance between the light source and the Elodea plant.
3. Fill a beaker with water and add a small amount of sodium hydrogen carbonate to provide carbon dioxide for photosynthesis.
4. Place the Elodea plant in the beaker, ensuring that it is fully submerged in water.
5. Turn on the lamp and allow the Elodea to acclimate to the initial light intensity for 5 minutes.
6. Use the light meter to measure the intensity of the light hitting the Elodea in lux units and record the value.
7. Start the stopwatch and measure the rate of oxygen bubbles released by the Elodea for a fixed time period, e.g., 1 minute.
8. Repeat steps 5-7 for a total of 5 different light intensities, adjusting the distance between the light source and the Elodea for each intensity.
9. Calculate the rate of photosynthesis by dividing the number of oxygen bubbles released by the time period.
10. Repeat the entire experiment two more times to ensure accuracy.
Sample Data:
Light Intensity (lux) | Oxygen Bubbles (per minute)
-------------------------------------------------
500 | 3
1000 | 5
1500 | 7
2000 | 9
2500 | 11
Results:
The data obtained from the experiment shows a positive relationship between light intensity and the rate of photosynthesis in Elodea. As the light intensity increased, the number of oxygen bubbles released by the plant per minute also increased.
Discussion:
The results obtained support the hypothesis that increasing light intensity leads to an increased rate of photosynthesis in Elodea. This demonstrates the importance of light as a limiting factor for photosynthesis. The increase in oxygen bubble production suggests that the plant was able to produce more glucose, indicating a higher rate of photosynthesis.
Possible sources of error in this experiment include variations in the distance between the light source and the Elodea, inconsistencies in the light meter measurement, and variations in ambient conditions such as temperature and carbon dioxide levels. To minimize these errors, the experiment was repeated multiple times, and the average of the results was used for analysis.
Conclusion:
In conclusion, this experiment showed that increasing light intensity positively affects the rate of photosynthesis in Elodea. Further investigations could explore the effects of other environmental factors, such as temperature and carbon dioxide concentration, on the rate of photosynthesis in different plant species. It is important to understand these factors for agricultural purposes and to gain insights into the dynamics of natural ecosystems.
You left out control
I apologize for the oversight. Here is the revised procedure including a control:
Procedure:
1. Set up a workspace near a power source and place the lamp at a specific distance from the Elodea plant.
2. Measure and record the initial distance between the light source and the Elodea plant.
3. Fill a beaker with water and add a small amount of sodium hydrogen carbonate to provide carbon dioxide for photosynthesis.
4. Place the Elodea plant in the beaker, ensuring that it is fully submerged in water.
5. Turn on the lamp and allow the Elodea to acclimate to the initial light intensity for 5 minutes.
6. Use the light meter to measure the intensity of the light hitting the Elodea in lux units and record the value. This will serve as the control light intensity.
7. Start the stopwatch and measure the rate of oxygen bubbles released by the Elodea for a fixed time period, e.g., 1 minute.
8. Repeat steps 5-7 for a total of 5 different light intensities, adjusting the distance between the light source and the Elodea for each intensity.
9. Calculate the rate of photosynthesis by dividing the number of oxygen bubbles released by the time period.
10. Repeat the entire experiment two more times to ensure accuracy.
By including the control, we can compare the rate of photosynthesis at different light intensities to the baseline rate under the control conditions. This will help to isolate the effect of light intensity on the rate of photosynthesis.