M. Vowles TpT

Name: _______________________

Pre-lab questions

Write the general equation for photosynthesis below.

What factors affect the rate of photosynthesis?

http://www.kscience.co.uk/animations/photolab.swf

Click this link to go to the photosynthesis experiment.

#1. Effect of Light Intensity on Photosynthesis

Directions: First, you will try changing the light intensity (you will

be using the slider above the light bulb). Remember, do not

change any other factors; this is a controlled experiment.

Make a hypothesis; how will changing light intensity change the rate of photosynthesis?

Hypothesis:

______________________________________________________________________

______________________________________________________________________

Choose 5 different light intensity levels to test. Record the number of bubbles formed

over 30 seconds.

Data Table 1. Effect of Light Intensity on Photosynthesis

Trial Light intensity # Bubbles/30 seconds

1

2

3

4

5

M. Vowles TpT

Name: _______________________

Graph your data from the table below.

Figure 1. Effect of Light intensity on Photosynthesis

Analysis Questions

1. Describe general trend(s) in the data you graphed.

______________________________________________________________________

______________________________________________________________________

______________________________________________________________________

2. Was your hypothesis supported? _______________ Explain using specific

evidence from your data table and graph.

______________________________________________________________________

______________________________________________________________________

______________________________________________________________________

M. Vowles TpT

Name: _______________________

#2. Effect of Temperature on Photosynthesis

Directions: Now, try changing temperature (with light intensity at 25). Remember, do

not change any other factors; this is a controlled experiment.

Make a hypothesis; how will changing temperature change the rate of photosynthesis?

Hypothesis:

______________________________________________________________________

______________________________________________________________________

Test the three different temperatures. Record the number of bubbles formed over 30

seconds.

Data Table 2. Effect of Temperature on Photosynthesis

Trial Temperature (⁰C) # Bubbles/30 seconds

1

2

3

Graph your data from the table below.

Figure 2. Effect of Temperature on Photosynthesis

M. Vowles TpT

Name: _______________________

Analysis Questions

1. Describe general trend(s) in the data you graphed.

______________________________________________________________________

______________________________________________________________________

______________________________________________________________________

2. Was your hypothesis supported? _______________ Explain using specific

evidence from your data table and graph.

______________________________________________________________________

______________________________________________________________________

______________________________________________________________________

#3. Effect of CO2 on Photosynthesis

Directions: Now, try changing the amount of CO2, (with light intensity

at 25, and temperature at 25). Remember, do not change any other

factors; this is a controlled experiment.

Make a hypothesis; how will changing the amount of CO2 change the

rate of photosynthesis?

Hypothesis:

______________________________________________________________________

______________________________________________________________________

Test both levels of CO2. Record the number of bubbles formed over 30 seconds.

Data Table 3. Effect of CO2 on Photosynthesis

Trial Amount of CO2 # Bubbles/30 seconds

1

2

M. Vowles TpT

Name: _______________________

Graph your data from the table below.

Figure 3. Effect of CO2 on Photosynthesis

Analysis Questions

1. Describe general trend(s) in the data you graphed.

______________________________________________________________________

______________________________________________________________________

______________________________________________________________________

2. Was your hypothesis supported? _______________ Explain using specific

evidence from your data table and graph.

______________________________________________________________________

______________________________________________________________________

______________________________________________________________________

M. Vowles TpT

Name: _______________________

#4. Effect of Light Color on Photosynthesis

Directions: Now, try changing the color of light, (with light intensity at

25, and temperature at 25, and CO2 at 50%). Remember, do not

change any other factors; this is a controlled experiment.

Make a hypothesis; how will changing the color of light change the rate

of photosynthesis?

Hypothesis:

Test all the light colors. Record the number of bubbles formed over 30 seconds.

Data Table 4. Effect of Light Color on Photosynthesis

Trial Light Color # Bubbles/30 seconds

1

2

3

4

Graph your data from the table below.

Figure 4. Effect of Light Color on Photosynthesis

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button

_______________________________________________________

_______________________________________________________

M. Vowles TpT

Name: _______________________

Analysis Questions

1. Describe general trend(s) in the data you graphed.

______________________________________________________________________

______________________________________________________________________

______________________________________________________________________

2. Was your hypothesis supported? _______________ Explain using specific

evidence from your data table and graph.

______________________________________________________________________

______________________________________________________________________

______________________________________________________________________

Conclusion Questions

Describe the conditions that produce the most bubbles.

Explain why each of the conditions had an effect on bubble formation.

Light intensity:

______________________________________________________________________

______________________________________________________________________

______________________________________________________________________

______________________________________________________________________

Temperature:

______________________________________________________________________

______________________________________________________________________

______________________________________________________________________

______________________________________________________________________

Carbon dioxide:

______________________________________________________________________

______________________________________________________________________

______________________________________________________________________

______________________________________________________________________

M. Vowles TpT

Name: _______________________

Light color:

______________________________________________________________________

______________________________________________________________________

______________________________________________________________________

______________________________________________________________________

Identify the gas that is present in the bubbles: ___________________

M. Vowles TpT

Name: __________Key____________

Pre-lab questions

Write the general equation for photosynthesis below.

CO2 + Water + Light O2 + Glucose

What factors affect the rate of photosynthesis?

CO2, water, and light all affect the rate of photosynthesis because they are needed in

the reaction.

http://www.kscience.co.uk/animations/photolab.swf

Click this link to go to the photosynthesis experiment.

#1. Effect of Light Intensity on Photosynthesis

Directions: First, you will try changing the light intensity (you will

be using the slider above the light bulb). Remember, do not

change any other factors; this is a controlled experiment.

Make a hypothesis; how will changing light intensity change the rate of photosynthesis?

Hypothesis: Student answers will vary. In general, it must be a prediction and related

to light intensity and photosynthesis.

Choose 5 different light intensity levels to test. Record the number of bubbles formed

over 30 seconds.

Data Table 1. Effect of Light Intensity on Photosynthesis

Trial Light intensity # Bubbles/30 seconds

1 5 3

2 15 6

3 25 9

4 35 10

5 50 12

M. Vowles TpT

Name: __________Key____________

Graph your data from the table below.

Figure 1. Effect of Light intensity on Photosynthesis

Analysis Questions

1. Describe general trend(s) in the data you graphed.

As light intensity increases, the number of bubbles produced by the plant

increases. Therefore, increased light intensity increases photosynthesis.

2. Was your hypothesis supported? Answers vary Explain using specific evidence

from your data table and graph.

______________________________________________________________________

______________________________________________________________________

______________________________________________________________________

0

2

4

6

8

10

12

14

0 10 20 30 40 50 60

# B

UB

BLE

S/3

0 S

EC.

LIGHT INTENSITY

Effect of Light Intensity on Photosynthesis

# Bubbles/30 sec

M. Vowles TpT

Name: __________Key____________

#2. Effect of Temperature on Photosynthesis

Directions: Now, try changing temperature (with light intensity at 25). Remember, do

not change any other factors; this is a controlled experiment.

Make a hypothesis; how will changing temperature change the rate of photosynthesis?

Hypothesis: Student answers will vary. In general, it must be a prediction and related

to temperature and photosynthesis.

Test the three different temperatures. Record the number of bubbles formed over 30

seconds.

Data Table 2. Effect of Temperature on Photosynthesis

Trial Temperature (⁰C) # Bubbles/30 seconds

1 10 10

2 25 28

3 40 22

Graph your data from the table below.

Figure 2. Effect of Temperature on Photosynthesis

0

5

10

15

20

25

30

0 10 20 30 40 50

# B

ub

ble

s/3

0 s

ec

Temperature (⁰C)

Effect of Temperature on Photosynthesis

# Bubbles/30 sec

M. Vowles TpT

Name: __________Key____________

Analysis Questions

3. Describe general trend(s) in the data you graphed.

The optimal temperature for photosynthesis is around 25⁰C. 25⁰C produces the

greatest number of bubbles, indicating a high rate of photosynthesis.

4. Was your hypothesis supported? Answers vary Explain using specific evidence

from your data table and graph.

______________________________________________________________________

______________________________________________________________________

______________________________________________________________________

#3. Effect of CO2 on Photosynthesis

Directions: Now, try changing the amount of CO2, (with light intensity

at 25, and temperature at 25). Remember, do not change any other

factors; this is a controlled experiment.

Make a hypothesis; how will changing the amount of CO2 change the

rate of photosynthesis?

Hypothesis: Student answers will vary. In general, it must be a prediction and related

to carbon dioxide concentration and photosynthesis.

Test both levels of CO2. Record the number of bubbles formed over 30 seconds.

Data Table 3. Effect of CO2 on Photosynthesis

Trial Amount of CO2 # Bubbles/30 seconds

1 50% 28

2 100% 18

M. Vowles TpT

Name: __________Key____________

Graph your data from the table below.

Figure 3. Effect of CO2 on Photosynthesis

Analysis Questions

3. Describe general trend(s) in the data you graphed.

As CO2 concentration increased, the number of bubbles formed by the plant decreased.

4. Was your hypothesis supported? Answers vary Explain using specific evidence

from your data table and graph.

______________________________________________________________________

______________________________________________________________________

______________________________________________________________________

0

5

10

15

20

25

30

0% 20% 40% 60% 80% 100% 120%

# B

ub

ble

s/3

0 s

ec

Carbon Dioxide Concentration

Effect of Carbon Dioxide on Photosynthesis

# Bubbles/30 sec

M. Vowles TpT

Name: __________Key____________

#4. Effect of Light Color on Photosynthesis

Directions: Now, try changing the color of light, (with light intensity at

25, and temperature at 25, and CO2 at 50%). Remember, do not

change any other factors; this is a controlled experiment.

Make a hypothesis; how will changing the color of light change the rate

of photosynthesis?

Hypothesis:

Test all the light colors. Record the number of bubbles formed over 30 seconds.

Data Table 4. Effect of Light Color on Photosynthesis

Trial Light Color # Bubbles/30 seconds

1 White 28

2 Red 21

3 Green 8

4 Blue 24

Graph your data from the table below.

Figure 4. Effect of Light Color on Photosynthesis

0

5

10

15

20

25

30

Light Color

# B

ub

ble

s/3

0 s

ec

The Effect of Light Color on Photosynthesis

White

Red

Green

Blue

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button

Student answers will vary. In general, it must be a prediction and

related to light color and photosynthesis.

M. Vowles TpT

Name: __________Key____________

Analysis Questions

3. Describe general trend(s) in the data you graphed.

White light had the highest number of bubbles. Blue had the second highest number of

bubbles, while red was next. Green had the least number of bubbles and thus the

lowest rate of photosynthesis.

4. Was your hypothesis supported? Answers vary Explain using specific evidence

from your data table and graph.

______________________________________________________________________

______________________________________________________________________

______________________________________________________________________

Conclusion Questions

Describe the conditions that produce the most bubbles.

White light with 50% CO2, 50 light intensity and 25⁰C.

Explain why each of the conditions had an effect on bubble formation.

Light intensity:

Sunlight is required for photosynthesis. Sunlight excites electrons used to ultimately

generate sugar. The greater the intensity of the sun, the more electrons that are excited

and the greater the rate of photosynthesis.

Temperature:

Since there are many enzymes that control photosynthesis, temperature impacts the

rate at which enzymes act. Too high of a temperature can start to denature enzymes

and will slow reactions such as photosynthesis. Maximum photosynthetic rate occurs at

the enzymes optimum working conditions.

Carbon dioxide:

Carbon dioxide is fixed by the enzyme rubisco to form sugar during photosynthesis. We

would expect that as carbon dioxide levels increase, the rate of photosynthesis would

plateau because there are only so many active sites CO2 can bind to on the enzyme.

The results of this lab are unusual and may be due to lab error.

M. Vowles TpT

Name: __________Key____________

Light color:

White light contains all wavelengths of light including blue and red. Green light has the

lowest rate of photosynthesis because green plants reflect green light.

Identify the gas that is present in the bubbles: Oxygen