SBI4U Photosynthesis Lab Gizmo

Name: ______________________________________ Date: ________________________

Photosynthesis Lab

Gizmo website: www.explorelearning.com Class code: EFVNHTVRGY

Gizmo Warm-up
During photosynthesis, plants use the energy of light to produce glucose (C6H12O6) from carbon dioxide (CO2), and water (H2O). Glucose is a simple sugar that plants use for energy and as a building block for larger molecules.

A by-product of photosynthesis is oxygen. Plants use some of the oxygen they produce, but most of it is released. In the Photosynthesis Lab Gizmo™, you can monitor the rate of photosynthesis by measuring oxygen production.

1. Observe the left pane closely. What do you think the bubbles are? __________________[1]
2. Select the BAR CHART tab. On the graph, notice the Oxygen production bar. Move the Light intensity slider back and forth. How does light intensity affect oxygen production? _______________________________________________________________________[1]

3. Experiment with the vertical Temperature slider (upper left) and the CO2 level slider.

A. How does temperature affect oxygen production? ___________________________

________________________________________________________________ [1]

B. How does CO2 level affect oxygen production? ______________________________

_________________________________________________________________[1]

C. How does oxygen production relate to the rate of photosynthesis? ______________

_________________________________________________________________[1]

Question: In the Gizmo, what are the ideal conditions for photosynthesis?

1. Form hypothesis: During photosynthesis, light energy is used to synthesize carbon dioxide (CO2) and water (H2O) into glucose (C6H12O6) and oxygen (O2). The complex series of chemical reactions is summarized by the following formula:

6CO2 + 6H2O + light energy  C6H12O6 + 6O2

In the Gizmo, what light intensity and CO2 level do you think will maximize the rate of photosynthesis? __________________________________________________________[1]
2. Experiment: Use the Gizmo to find the ideal conditions for photosynthesis. Use any method you like. When you think you have the answer, list the conditions below. [2]

Temperature
Light intensity
CO2 level
Oxygen production

3. Revise and repeat: One way to test if you’ve found the ideal conditions is to change each variable slightly from the value that you recorded above. If the oxygen production decreases with each change that you make, it is likely you have found the ideal conditions. If a small change causes oxygen production to increase, continue to experiment.

If necessary, revise your numbers in the table above.

4. Think and discuss: Think about the process of finding the ideal conditions.

A. Why would it be hard to find the ideal light intensity if the temperature were very hot or cold? ____________________________________________________________
_________________________________________________________________[1]

B. Why would it be hard to find the ideal CO2 level if the light intensity were very low? ___________________________________________________________________
_________________________________________________________________[1]

Introduction: Plants use a green pigment called chlorophyll to absorb light and convert its energy into a form that the plant can use. Chlorophyll gives plants their green color.

Question: What color of light is the best for photosynthesis?

1. Form hypothesis: Which color of light do you think will maximize the rate of photosynthesis?

_______________________________________________________________________[1]

2. Observe: The color of a light wave is determined by its wavelength. On the COLOR tab, slowly drag the Light wavelength slider back and forth and observe the effect on oxygen production. How does the color of light affect the rate of photosynthesis?
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_________________________________________________________________________

_______________________________________________________________________[1]
3. Gather data: Set the Light wavelength to 400 nm. (The symbol “nm” stands for nanometers. A nanometer is a billionth of a meter.) Visible light ranges from 400 to 700 nm.

On the TABLE tab, click Record data. Then set the Light wavelength to 420 nm, and repeat. Continue recording data in the Gizmo every 20 nm until the wavelength is 700 nm.

4. Make a graph: Select the GRAPH tab and select Wavelength. Sketch the graph in the space at right.
[1]

A. Which colors were absorbed best by the plant? ___________________________[1]
B. Which colors were absorbed worst?

_________________________________[1]

5. Think and discuss: When we look at a leaf, we see the colors of light that are reflected off its surface. How does this explain the relatively low flow of oxygen in green light?

_________________________________________________________________________

_______________________________________________________________________[1]

Introduction: Photosynthesis requires light, water, and CO2 to work. When one of these factors is in short supply, it is called a limiting factor. Temperature can also be a limiting factor when it is too hot or too cold for photosynthesis to work well.

Question: What is the effect of limiting factors on photosynthesis?

1. Observe: Set Temperature to 24°C, Light intensity to 50%, and CO2 level to 200 ppm.
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A. Move the Temperature slider up and down. Were you able to increase oxygen production? _____________________[1] (Return the slider to 24°C when finished.)
B. Move the Light intensity slider back and forth. Were you able to increase oxygen production? _____________________[1] (Return the slider to 50% when finished.)
C. Move the CO2 level slider back and forth. Were you able to increase oxygen production? _____________________[1] (Return the slider to 200 ppm when finished.)
2. Analyze: In this situation, what was the limiting factor? _____________________________ [1]

How do you know? __________________________________________________________[1]

3. Challenge: In each of the situations below, use the Gizmo to find the limiting factor. [3]

Temperature
Light intensity
CO2 level
Limiting factor
25°C
60%
700 ppm

15°C
20%
200 ppm

30°C
50%
400 ppm

4. Think and discuss: Suppose you were a farmer trying to grow plants in a greenhouse. Why would it be important to know what the limiting factor is?

_________________________________________________________________________

_______________________________________________________________________ [1]

Photosynthesis Lab Evaluation Scheme:

Part 1: Correct answers to the above investigation questions TI : /25

Part 2: Discussion and Conclusion Com: /25

Requirements
Level 1(50-59%)
Level 2 (60-69%)
Level 3 (70-79%)
Level 4 (80-100%)
Cover page, Title, Name, Date, Course Code, Teacher’s Name
Headings, Proper paragraphing, 11-12 font in arial or times new roman /2
Few requirements present.
Some requirements present.
Most requirements present.
All requirements present.
Clarity, flow, grammar & spelling

/8
Writing has limited clarity and flow. Many spelling and grammatical errors. Third-person voice, past tense are not kept consistent.
Writing has some clarity and flow. Some spelling and grammatical errors. Third-person voice, past tense are kept somewhat consistent.
Writing has considerable clarity and flow. Few spelling and grammatical errors. Third-person voice, past tense are mostly kept consistent.
Writing has excellent clarity and flow. Very few or no spelling and grammatical errors. Third-person voice, past tense are kept consistent.
Contents
-discussion of results and analysis questions
-relation to 2 resrouces

/10
Some results are not discussed. Some analysis and thinking questions are not related to the results and previous studies (2 references)
Results are discussed with little details for all three activities. Analysis and thinking questions are answered with some relation to the results and previous studies (2 references)
Results are discussed in some details for all three activities. Most analysis and thinking questions are answered relating to the results and previous studies (2 references)
Results are discussed in details for all three activities. Analysis and thinking questions are answered relating to the results and previous studies (2 references)
Conclusion
-compare hypothesis to the results
-suggest 1 area of future study

/3
Hypothesis for the activities are not restated or not compared to the results. One area of future investigation is not suggested.
Hypothesis for the activities are not fully restated or not fully compared to the results. One area of future investigation is not suggested.
Hypothesis for the activities are not fully restated but compared to the results. One area of future investigation is suggested without a reason given.
Hypothesis for the activities are restated and compared to the results. One area of future investigation is suggested with a reason.
Back up the results and discussion with at least 2 resources /2
Reference list is in APA format with many errors.
No in-text citations.
Reference list is in APA format with some errors.
Reference list is in APA format with few errors.
Reference list is in APA format with no errors. Proper in-text citations.