Beacon High School
Name________________________________________
Class__________
Date_____________
Photosynthesis Lab
Problem: How does increasing light impact the rate (speed) of photosynthesis?
Hypothesis: (If...then…because…)
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Procedure
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Take an Elodea Plant. Cut a tiny tiny tiny piece off the bottom of the stem.
Put a small binder clip on the top of the elodea plant and put it in a glass beaker.
Fill up the beaker with 500 mL of water.
The part of the plant stem you cut should be facing upwards but still submerged in water.
Add 1 tablespoon of Baking Soda. *Baking Soda when added to water becomes a source of Carbon Dioxide*
Observe the Elodea Plant for 5 minutes using a timer. Count the number of bubbles that come out of the stem
(the part you cut) and record the number in the data table below.
7. Turn on the flashlight on your cell phone and shine the light directly on the Elodea Plant.
8. Observe the Elodea Plant for 5 minutes using a timer. Count the number of bubbles that come out of the stem
and record it in the data table below in the column that says “Increased amount of light using a lamp/or cell
phone”
9. Create a bar graph on the attached graph grid.
a. Write an appropriate title (check your graphing notes).
b. Label the x and y axis with the appropriate title.
c. The y-axis needs an appropriate scale.
d. Create two bars for the class average.
Results/Data Table
Regular Light of a classroom
Bubbles released in
5 minutes
Class Average
Increased Light using a Lamp/or cell phone
Answer in complete sentences
What is the chemical formula for photosynthesis?
Which setup had a faster rate of photosynthesis (without the lamp or with the lamp)? How do you know?
Why did you add baking soda to the beaker?
What was the product of photosynthesis that was creating the bubbles?
Identify the independent variable in this experiment.
Identify the dependent variable in this experiment. How was the dependent variable measure?
What are three constants in this experiment?
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Discussion/Summary Section (Answer in complete sentences)
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What impact does increasing the amount of light have on the rate of photosynthesis?
What data supports your previous statement? (reference the numbers in your data table)
If you observe more bubbles emerging from the plant, what can you infer about the amount of glucose being
produced?
How would you increase the validity of the experiment?
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Analysis Question (Answer in complete sentences)
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What would happen to the rate of photosynthesis if you decrease the amount of baking soda in the beaker?
Why?
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What would happen if the water in the beaker ran out? What impact would this have on the homeostasis?