Question

For unit 7 lesson 3, 4, and 5 you will be working on a portfolio assignment about photosynthesis. You will be asked to conduct two investigations. You can choose to complete one of the investigations or both of them. Please make sure that you read the directions in each lesson carefully so you know what to do. Please also watch the videos and use the grading rubric provided within the lessons.

You are not taking any assessments or uploading anything in lesson 3 and 4 but you will upload your completed lab report and your labeled diagram of the photosynthesis process in lessons 5.

Here is a breakdown of what you will do throughout lessons 3, 4, and 5:

Create a labeled diagram of the photosynthesis process
Conduct an investigation on how carbon dioxide gas is taken in by leaves during photosynthesis and an investigation on how oxygen gas is released during photosynthesis
Or you can choose to do either the carbon dioxide or the oxygen gas investigation from number 2. Please ask your teacher for help in office hours if you are confused.
Describe the collected data
Graph your collected data
Explain why the data provides evidence for the exchange of gases during photosynthesis
Evaluate your results (you can write a 5 - 7 sentence summary of your results)
When you are finished with #1-7 above, you will upload your completed lab report with the 5 points below on page 8 of lesson 5:

1.Your labeled diagram of the photosynthesis process.

2. A complete lab report with the following details:

A 5 sentence paragraph on how you conducted your investigations
The graph of your data and a 5 sentence paragraph of what you concluded,
Evaluate your results by writing a 5 - 7 sentence summary of your knowledge of gas exchange. write it as a 6th grader

Answer 1

Below is a ready-to-use set of items you can upload on page 8 of lesson 5. I wrote everything in a clear 6th-grade voice. Copy, paste, or draw the diagram and use the sample data and graph directions to make your own graph.

1) Labeled diagram of the photosynthesis process (draw this and label the parts)
- Draw a leaf (side view) and a zoomed-in chloroplast inside a leaf cell.
- Label: Sunlight (arrow coming from above into the leaf). Stomata (tiny hole on the bottom of the leaf) with an arrow pointing in labeled "CO2 in (carbon dioxide enters here)". Roots (arrow up labeled "Water from roots"). Chloroplast (green oval inside the cell). Inside the chloroplast write: Thylakoids (stacked disks) and Stroma (fluid). Add arrows inside the chloroplast: Light + Water -> Oxygen (O2) (arrow out), and Carbon dioxide (CO2) -> Glucose (C6H12O6) (arrow to the plant). Label outputs: "O2 leaves the leaf" and "Glucose used by the plant."
- Short caption under the diagram: "Photosynthesis: Sunlight + CO2 + H2O -> Glucose + O2. CO2 enters through stomata, water comes from roots, and O2 leaves the leaf."

2) Complete lab report

A. Five-sentence paragraph on how I conducted my investigations
I did two simple investigations to study photosynthesis. First, I used Elodea (aquatic plant) in test tubes with a little baking soda solution and put the tubes under low, medium, and bright light, then counted oxygen bubbles every minute. Second, I used a small jar with a leaf in bromothymol blue (a CO2 color indicator) and watched the color change over time while the jar sat in bright light and in the dark. I kept the same temperature and used the same size plant pieces so the tests were fair. I recorded my counts and color changes every five minutes for thirty minutes.

B. Graph of your data and a five-sentence conclusion
- Oxygen-release data table (count of bubbles per minute from Elodea)
Light level: Low -> 2 bubbles/min
Light level: Medium -> 6 bubbles/min
Light level: Bright -> 12 bubbles/min

- CO2-uptake data table (bromothymol blue color shown as pH reading)
Condition: Dark -> pH 6.0 (yellowish)
Condition: Low light -> pH 6.4 (green-yellow)
Condition: Bright light -> pH 7.0 (blue-green)

How to make the graphs:
- Graph 1 (Oxygen): x-axis = Light level (Low, Medium, Bright). y-axis = Bubbles per minute. Plot points (Low,2), (Medium,6), (Bright,12). Connect points with a line or bars.
- Graph 2 (CO2): x-axis = Condition (Dark, Low, Bright). y-axis = pH (or color change scale). Plot (Dark,6.0), (Low,6.4), (Bright,7.0). Connect points or use bars.

Five-sentence conclusion (write-up):
The oxygen graph shows more bubbles when the light is brighter, so the plant made more oxygen in bright light. The CO2 indicator got less acidic (higher pH) in bright light, which means the plant used up CO2. Both sets of data show that light increases photosynthesis. This tells us that when plants get more light they take in more CO2 and release more O2. So my data supports that gas exchange happens during photosynthesis.

C. Evaluate your results (5–7 sentence summary of your knowledge of gas exchange) — written as a 6th grader (I used 6 sentences)
My results matched what I learned about photosynthesis in class. Plants use carbon dioxide from the air and water from the soil to make sugar and oxygen when light is available. The CO2 indicator becoming less acidic in the light showed that CO2 was being removed by the leaf. The Elodea making more oxygen bubbles in brighter light showed that oxygen is a product of photosynthesis. I controlled the tests so that light was the main thing changing and that helped make the evidence stronger. This means plants exchange gases (take in CO2 and give off O2) and they do it faster when they get more light.

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If you want, I can:
- Make a printable label sheet you can paste next to the diagram.
- Turn the sample data into a simple image graph (you would download it and upload in lesson 5).
- Change the investigations to only do one experiment instead of both.

Which would you like next?