Student Exploration: Photosynthesis Lab
Vocabulary: carbon dioxide, chlorophyll, glucose, limiting factor, nanometer, photosynthesis,
wavelength
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
• To survive, what gas do we need to breathe in?
o Oxygen
• Where is this gas produced?
o This gas is produced from plants during photosynthesis
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?
A. In my opinion, the bubbles are the oxygen that the plant is giving off
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?
A. The greater the light intensity is, the oxygen production is also greater. The
oxygen production begins to decrease at a light intensity of 37%.
3. Experiment with the vertical Temperature slider (upper left) and the CO2 level slider.
A. How does temperature affect oxygen production?
i. Temperatures between 17 and 31 degrees do not have an affect on
oxygen production. When the temperature exceeds 31 degrees the
production of oxygen decreases.
B. How does CO2 level affect oxygen production?
i. A CO2 level of a ppm of 230 and above has no impact on the oxygen
production. When lower than 230ppm oxygen production along with CO2
levels decrease.
C. How does oxygen production relate to the rate of photosynthesis?
, Get the Gizmo ready:
Activity A:
• Be sure that the BAR CHART tab is selected.
Ideal conditions • Turn on Show numerical values.
i. Oxygen production relates to the rate of photosynthesis because oxygen is
product that occurs during photosynthesis. If more oxygen is being
produced more reactions are taking place at a higher rate.
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?
- I think that the highest light intensity and CO2 available will maximize the rate of
photosynthesis.
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.
Temperature Light intensity CO2 level Oxygen production
88 25 890 51.8
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?
Vocabulary: carbon dioxide, chlorophyll, glucose, limiting factor, nanometer, photosynthesis,
wavelength
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
• To survive, what gas do we need to breathe in?
o Oxygen
• Where is this gas produced?
o This gas is produced from plants during photosynthesis
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?
A. In my opinion, the bubbles are the oxygen that the plant is giving off
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?
A. The greater the light intensity is, the oxygen production is also greater. The
oxygen production begins to decrease at a light intensity of 37%.
3. Experiment with the vertical Temperature slider (upper left) and the CO2 level slider.
A. How does temperature affect oxygen production?
i. Temperatures between 17 and 31 degrees do not have an affect on
oxygen production. When the temperature exceeds 31 degrees the
production of oxygen decreases.
B. How does CO2 level affect oxygen production?
i. A CO2 level of a ppm of 230 and above has no impact on the oxygen
production. When lower than 230ppm oxygen production along with CO2
levels decrease.
C. How does oxygen production relate to the rate of photosynthesis?
, Get the Gizmo ready:
Activity A:
• Be sure that the BAR CHART tab is selected.
Ideal conditions • Turn on Show numerical values.
i. Oxygen production relates to the rate of photosynthesis because oxygen is
product that occurs during photosynthesis. If more oxygen is being
produced more reactions are taking place at a higher rate.
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?
- I think that the highest light intensity and CO2 available will maximize the rate of
photosynthesis.
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.
Temperature Light intensity CO2 level Oxygen production
88 25 890 51.8
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?
