Experiment 1 Contents of Test Tube Original Color Observed Color After 24 Hours Test Tube 1: BTB solution, blown into using a straw Yellow Yellow Test Tube 2: BTB solution, blown into using a straw, and Elodea Sprigs. Yellow Blue Test Tube 3: BTB solution, blown into using a straw, Elodea Sprigs and covered in foil. Yellow Yellow The above data is based on three trials. One being the control with only BTB solution that has been blown into with a straw. Another containing the BTB that has been blown into with a straw, and Elodea. The last containing the BTB that has been blown into with a straw, the Elodea, and covered in foil to block the light. Investigation 2 Experiment 2 Time Elapsed Test Tube 1 (In the Light) - Number of Bubbles Test Tube 2 (In the Dark) - Number of Bubbles 0 minutes 0 0 1 minute 20 1 2 minutes 31 0 3 minutes 32 0 4 minutes 31 2 5 minutes 32 1 The above data is based on two test tubes containing the same contents. Test tube one is in the light and test tube 2 is in the dark.
17 answers
In experiment 1, three test tubes were used. Test tube 1 contained BTB solution and was blown into using a straw. This served as the control. Test tube 2 contained BTB solution, Elodea sprigs, and was blown into using a straw. Test tube 3 contained BTB solution, Elodea sprigs, and was covered in foil to block the light.
After 24 hours, the observed colors of the solutions were recorded. Test tube 1 remained yellow, indicating that blowing into the BTB solution does not change its color. Test tube 2 turned blue, indicating that the Elodea plants produced oxygen, which reacted with the BTB solution. Test tube 3 remained yellow, indicating that the presence of foil blocked the light and inhibited the reaction.
In experiment 2, two test tubes were used. Both test tubes contained the same contents: BTB solution and Elodea sprigs. Test tube 1 was placed in the light and test tube 2 was placed in the dark.
The number of bubbles produced by the Elodea plants was recorded at different time intervals. In test tube 1 (in the light), there were 0 bubbles at the start, but the number increased to 32 bubbles after 5 minutes. In test tube 2 (in the dark), there were 0 bubbles at the start, and the number remained low throughout the experiment, with only 2 bubbles observed at 4 minutes.
This data suggests that Elodea plants produce more bubbles (indicating more oxygen production) in the presence of light compared to when they are in the dark.
- Test tube 1: BTB solution
- Test tube 2: BTB solution, Elodea sprigs
- Test tube 3: BTB solution, Elodea sprigs, foil
- Straw for blowing into the test tubes
- Foil for covering test tube 3 (if applicable)
Experiment 2:
- Test tube 1: BTB solution, Elodea sprigs (placed in the light)
- Test tube 2: BTB solution, Elodea sprigs (placed in the dark)
- Timer or stopwatch to measure time intervals
Experiment 1:
- Test tube 1: BTB solution
- Test tube 2: BTB solution, Elodea sprigs
- Test tube 3: BTB solution, Elodea sprigs, foil
- Straw for blowing into the test tubes
- Foil for covering test tube 3 (if applicable)
Experiment 2:
- Test tube 1: BTB solution, Elodea sprigs (placed in the light)
- Test tube 2: BTB solution, Elodea sprigs (placed in the dark)
- Timer or stopwatch to measure time intervals
Please note that this list assumes that no other equipment or materials were mentioned or used in the experiments.
Your procedure should be written so that anyone else could repeat the experiment.
1. Gather the following materials: test tubes, BTB solution (bromothymol blue), Elodea sprigs, straw, foil (optional).
2. Label test tubes 1, 2, and 3 accordingly.
3. Fill test tube 1 with BTB solution.
4. Fill test tube 2 with BTB solution and add Elodea sprigs.
5. Fill test tube 3 with BTB solution, add Elodea sprigs, and cover it with foil to block light (optional).
6. Use a straw to blow into each test tube for a few seconds to introduce carbon dioxide into the solutions.
7. Let the test tubes sit undisturbed for 24 hours.
8. After 24 hours, observe and record the color of each test tube. Test tube 1 should remain yellow, indicating no change. Test tube 2 should turn blue, indicating oxygen production through photosynthesis. Test tube 3, if covered in foil, should remain yellow due to the absence of light.
Experiment 2: Assessing Oxygen Production in the Presence and Absence of Light
1. Collect the necessary supplies: test tubes, BTB solution, Elodea sprigs, timer or stopwatch.
2. Label test tubes 1 and 2 accordingly.
3. Fill both test tubes with BTB solution.
4. Add Elodea sprigs to both test tubes.
5. Place test tube 1 in a well-lit area and test tube 2 in a dark or shaded area.
6. Start the timer and record the number of bubbles produced by the plants at specific time intervals (e.g., 1 minute, 2 minutes, etc.).
7. Repeat the measurements for the desired duration of the experiment (e.g., 5 minutes, 10 minutes).
8. Observe and record the number of bubbles produced in each test tube. Test tube 1 should show an increase in the number of bubbles over time, indicating oxygen production due to photosynthesis in the presence of light. Test tube 2 should show minimal or no increase in the number of bubbles, indicating limited or no oxygen production in the absence of light.
Include a summary of what you learned from each investigation about photosynthesis and gas exchange.
Discuss possible errors that could have occurred in the collection of data.
Helpful format for writing a conclusion (length of blank lines does NOT indicate the length of your entries – additional sentences are encouraged)
This lab (experiment) investigated _________. In order to study the problem we ________. My results showed ________________.
I believe the results are (accurate/inaccurate) because ________________. In order to further investigate this problem, next time I would __________.
This lab investigated the effects of light on photosynthesis in Elodea plants by comparing the color changes in BTB solution when Elodea was present, with and without exposure to light. The results indicated that in the presence of light, Elodea plants produced oxygen through photosynthesis, as evidenced by the color change of the BTB solution from yellow to blue. When the solution was covered in foil to block light, there was no color change, indicating that the absence of light significantly reduced or inhibited photosynthesis.
Possible errors in data collection could include inaccurate observations of color changes or variations in the amount of Elodea sprigs used. Additionally, if the experiment was conducted in an area with inconsistent lighting conditions, it could have influenced the results. To further investigate this problem, in future experiments, more trials could be conducted, and light intensity could be controlled more precisely.
Investigation 2: Oxygen Production in the Presence and Absence of Light
This experiment aimed to assess the rate of oxygen production in Elodea plants when exposed to light versus being kept in the dark. The results demonstrated that in the presence of light, the number of bubbles produced by Elodea plants increased over time, indicating higher rates of oxygen production through photosynthesis. In contrast, in the dark, the number of bubbles remained low throughout the experiment, indicating limited or no oxygen production.
Potential errors in data collection include inaccuracies in counting the bubbles, variations in Elodea plant health or size, and potential inconsistencies in light conditions within the experiment. To further investigate this problem, it could be useful to use a more precise method for measuring oxygen production, such as a dissolved oxygen probe. Additionally, conducting the experiment in a controlled environment with consistent lighting conditions would help eliminate potential sources of error.
In summary, these investigations demonstrated the importance of light in photosynthesis and its direct impact on the production of oxygen in Elodea plants. The results were consistent with the known principles of photosynthesis and gas exchange. However, to ensure accuracy and precision, future experiments could incorporate more controls, increase the number of trials, and use more refined measurement techniques.
This section should include any data tables, observations, or additional notes you make during the lab.
You may attach a separate sheet(s) if necessary.
All tables, graphs and charts should be labeled appropriately.
Investigation 1: Effects of Light on Photosynthesis
In this investigation, the color changes in the BTB solution with different test tube contents and exposure to light were observed after 24 hours. The following observations were recorded:
Test Tube 1 (Control: BTB solution blown into with a straw):
- Original color: Yellow
- Observed color after 24 hours: Yellow
Test Tube 2 (BTB solution blown into with a straw, and Elodea sprigs):
- Original color: Yellow
- Observed color after 24 hours: Blue
Test Tube 3 (BTB solution blown into with a straw, Elodea sprigs, and covered in foil):
- Original color: Yellow
- Observed color after 24 hours: Yellow
These observations indicate that the presence of Elodea sprigs in the BTB solution resulted in a color change from yellow to blue, suggesting the production of carbon dioxide (CO2) from the plant through photosynthesis. Test Tube 3, which was covered in foil to block light, remained yellow, indicating the absence of photosynthesis and limited gas exchange.
Investigation 2: Rate of Gas Exchange in the Presence and Absence of Light
This investigation aimed to compare the rate of gas exchange, specifically the release of carbon dioxide (CO2), in the presence and absence of light. The number of bubbles released by the Elodea plants in test tubes placed in light and dark conditions were recorded at specific time intervals. The following data was collected:
Test Tube 1 (In the Light) - Number of Bubbles:
- 0 minutes: 0 bubbles
- 1 minute: 20 bubbles
- 2 minutes: 31 bubbles
- 3 minutes: 32 bubbles
- 4 minutes: 31 bubbles
- 5 minutes: 32 bubbles
Test Tube 2 (In the Dark) - Number of Bubbles:
- 0 minutes: 0 bubbles
- 1 minute: 1 bubble
- 2 minutes: 0 bubbles
- 3 minutes: 0 bubbles
- 4 minutes: 2 bubbles
- 5 minutes: 1 bubble
These results indicate that the Elodea plants released a higher number of bubbles, indicating the production of carbon dioxide (CO2), when exposed to light compared to being kept in the dark. The rate of gas exchange and CO2 release was significantly lower in the dark condition.
Please note that the data provided herein is based solely on the information you have given, and actual data may vary based on the specific details and measurements collected in the lab.