Use the lab report below to Complete the Unit 7 portfolio. This lab report is based on the lab investigations given in Connexus and will be using the provided videos. Some parts of this lab report have already been filled in for you. Be sure to write 1-2 complete sentences when answering questions. One word answers will not provide full credit.
You may want to view this video before you begin to truly understand what this investigation would look like.
Name
Date
Assignment Title: Unit 7 Portfolio: Matter and Energy
Before beginning you MUST watch the video in Lesson 3, page 10. Then, you can complete the first part of this lab report by answering the questions, writing a hypothesis, determining your variables, describing your materials, and listing your procedures. Remember, you don’t actually have to DO this experiment, but you do have to plan as if you are.
Steps of the Scientific Method
1. State the Problem
How much carbon dioxide does the plant Elodea absorb and how much oxygen does it release?
Why are two investigations needed to show gas exchange during photosynthesis?
How will we measure the amount of carbon dioxide that Elodea has absorbed?
How will we measure the amount of oxygen Elodea has released?
2. Hypothesis
Independent Variable
____________________
IF_______________________________________________,
THEN____________________________________________
________________________________________________.
Dependent Variable
____________________
3. Experiment
Control
Materials
Procedures (list steps)
1.
6.
2.
7.
3.
8.
4.
9.
5.
10.
Watch the video in Lesson 3, page 10 before moving forward.
4. Describe the data you expect to collect in this investigation by answering the questions. You can also insert a sample data table if you wish.
How will you determine whether photosynthesis has occurred? What color does BTB make the water to begin with? What color do you expect the water to be IF photosynthesis has occurred?
Answer the following questions.
If you place an Elodea plant in the BTB + baking soda solution overnight and in the morning it is yellow. What does that mean? Do you think there would be oxygen bubbles present?
Examine the example table to the right and answer the question that follows.
Content of Test Tube
Color When Left in Light
Color when left in Dark
11
Baking Soda + BTB
Yellow
Yellow
2
Baking Soda, BTB, and Elodea
Green
Greenish Yellow
3
Baking Soda, BTB, and Elodea
Green
Yellow
Which trial performed photosynthesis when left in the light? Which trial performed photosynthesis when left in the dark?
Examine the table to the right and answer the following questions.
Time Elapsed (minutes)
Test Tube 1 – Number of bubbles
Test Tube 2 – Number of Bubbles
0
0
0
1
20
23
2
31
31
3
32
35
4
31
32
5
32
33
Make a graph of the number of oxygen bubbles that are released per minute for 5 minutes. Plot the time in minutes on the horizontal axis and the number of bubbles on the vertical access.
If you cannot make the graph directly in this document, you will need to create your graph on paper and then upload a picture. If you cannot get it into this box, add it to the end of this lab report or attach a separate submission to the drop box.
Summarize your lab report by answering the following questions.
5. Conclusion: written explanation of what you learned. This should be one paragraph explaining what you learned about photosynthesis (5-6 sentences, 250 words). Be sure to include ALL required vocab words from the list above and underline them.
Information to include:
Did your data support or refute your hypothesis?
What would you do to improve the experiment in the future?
What did you learn about this topic?
My hypothesis is that if more light is provided, then the Elodea plant will absorb more carbon dioxide and release more oxygen. The independent variable is the amount of light provided, and the dependent variable is the amount of carbon dioxide absorbed and oxygen released by the Elodea plant.
For the experiment, we would need the following materials: Elodea plant, beaker, bromothymol blue (BTB) solution, baking soda, light source, timer, test tubes, and a data table.
The procedures for the experiment are as follows:
1. Fill the beaker with the BTB solution.
2. Add baking soda to the BTB solution to provide a source of carbon dioxide.
3. Place the Elodea plant in a test tube filled with BTB solution.
4. Place the test tube with the Elodea plant in the beaker with BTB solution.
5. Place the beaker with the test tube and Elodea plant under a light source.
6. Start the timer and observe for a specific amount of time.
7. Record the color of the BTB solution in the test tube at the beginning and end of the observation period.
8. Repeat the experiment with different amounts of light provided.
In this investigation, we expect to collect data on the color change of the BTB solution in the test tubes. BTB solution is initially blue, and if photosynthesis occurs, it will turn yellow due to the release of oxygen.
If an Elodea plant placed in the BTB + baking soda solution overnight turns yellow, it means that photosynthesis has occurred. In this case, we would expect oxygen bubbles to be present as well.
Based on the data table provided, trial 2 performed photosynthesis when left in the light, and trial 3 performed photosynthesis when left in the dark.
The graph of the number of oxygen bubbles released per minute for 5 minutes would show an increase in the number of bubbles over time.
In conclusion, our data supported the hypothesis that more light would result in more carbon dioxide absorption and oxygen release by the Elodea plant. To improve the experiment in the future, we could use a more precise method of measuring the amount of oxygen released and the amount of carbon dioxide absorbed. Additionally, conducting the experiment with a larger sample size would increase the reliability of the results. Through this investigation, we learned that photosynthesis is a vital process for plants to produce oxygen and absorb carbon dioxide.