Photosynthesis and
Elodea
By Matthew Abolafia
Abstract

Abstract
This lab is about Elodea and photosynthesis, and how the
distance of a light source affects the rate of photosynthesis. The
lab may influence plant growers to place their plants closer to a
light source, to increase the rate of photosynthesis. The
experiment proved that if the light source was too far away,
photosynthesis would be slower and less productive.
The procedure was to place Elodea under heat lamps and count
the bubbles of photosynthesis in test tubes. A higher count of
bubbles showed a higher rate of photosynthesis. The variables
were photosynthesis and the distance of the light source. The
results were recorded for 1 trial.
When the lamp was closest to the Elodea, the amount of bubbles
of photosynthesis was 39, a fast rate of photosynthesis. As the
lamp rose in height, the number of bubbles dropped, showing
slower rates of photosynthesis This experiment could influence
botanists who produce Elodea by helping to increase their
harvest rates.
Research: Part 1: Photosynthesis

Photosynthesis is a cycle gone through by plants to convert light into chemical energy for later use.
Photosynthesis starts in chloroplasts, which are a part of the plant. The chloroplasts capture chlorophyll,
an important chemical needed for photosynthesis. Chloroplasts also capture water, carbon dioxide,
oxygen and glucose. The chlorophyll is taken to the stroma, another part of the plant. In the stroma the
carbon dioxide and water blend together to make oxygen and glucose. The oxygen keeps all species on
earth alive because animal cells need an aerobic environment, or air filled environment to survive. The
glucose produced by the chloroplasts is used in many ways by different animals. Glucose is absorbed into
the animals’ bloodstream where it is used as a nutrient. Photosynthesis does not happen all at one time,
photosynthesis is divided into two important sections. The first is light-independent reactions. These
reactions happen when light energy is captured and made into a chemical known as Adenosine
triphosphate, or ATP. ATP is an enzyme used for reproduction, in a more modern term ATP is the
molecular unit of currency for reproduction. The second step of the process occurs when ATP is used to
create glucose, this is the light dependent reaction (Rader, 1997).

Photosynthesis takes electrons from water to energy-lacking carbon dioxide molecules, forming energetic
sugar molecules. This movement of electrons is an example of an oxidation reduction process. “The water
loses electrons and becomes oxidized,” (Pearson, 2014). Then, the oxidized water is taken to a different
species. Photosynthesis uses light energy to transfer electrons from water to more energetic states in sugar
molecules, therefore changing solar energy to chemical energy (Pearson, 2014).
Research: Part 2: Elodea

Elodea is also called: American elodea, common elodea, anacharis and Canada
waterweed (Aquatic Biologists, 2014). Elodea can grow in heights between 4 inches to
3 feet, depending on the depth of the body of water. Elodea is an underwater marine
plant with oval shaped leaves grouped into clusters of 3 or 4 around the stem that
provides shelter for fish and other sea organisms, and is an excellent producer of much
needed oxygen. Elodea is a food for geese and ducks, who feed on the fruit produced by
Elodea. Elodea reproduces by growing large buds in the springtime, relying very little
on seed reproduction. Because Elodea relies on a fragmenting process of breaking off
stem particles that sink to the ground and grow a new plant. But along with its
advantages, Elodea has some disadvantages. If populations of Elodea become overly
crowded, Elodea can reduce water temperatures, which can disturb sea life and possibly
kill them. Dense growth can become a poorer habitat for fish. Elodea is a common
aquarium plant, but even though it is very common, most people don’t know its name.
Its common name is “that aquarium plant.”(Rader, 1997; Swistock 2014). Elodea grows
in pond habitats and prospers in the fine sediment at the bottom of cool, spring-fed
ponds. Elodea is one of the few pond plants that can remain green throughout the cold
winter season.” (Swistock, 2014).
Question and Hypothesis

Question

\

Hypothesis
Does the distance of a light source from an Elodea plant affect the rate of
photosynthesis?

If the light source is closer to the plant, then the rate of
photosynthesis will be faster, because the light is closer and
more intense.
Variables and Materials

Variables

Materials
The independent variable was the distance of the light source
from the plant. The dependent variable was the rate of
photosynthesis of the Elodea plant.
Elodea (15.24 cm stem)
3 stems
Distilled Water
50 ml
500 ml Beaker
1
Heat Lamp
3
Test Tubes and Rack
1 Rack, 3 Test Tubes
Tape and Marker
1 of each
Goggles
1
Ruler (30.44 cm)
1
Scissors
1
Procedures
1. Put on necessary safety items (apron and goggles)
2. Obtain materials and label test tubes T1, T2, T3, and Ctrl

Procedures
3. Pour 50 ml of water in a single test tube
4. Place 15.24 cm Elodea in a single test tube and place test tube
on rack
5. Adjust heat lamps to heights of 25 cm, 31 cm, and 45 cm.
6. Place test tube rack under heat lamp of height indicated for
that trial
7. Turn lamp on and carefully count bubbles on Elodea stem for
5 minutes
8. Repeat steps 3-8 for trials 2 and 3
9. For Ctrl, time for five minutes outdoors in the sun
10. Record results in journal
Results
50
45
40
Lamp Height (cm) Bubbles counted
35
25
39
30
31
21
25
45
19
20
15
10
5
0
1
2
Lamp Height (cm)
3
Bubbles counted
Conclusion: Part 1

The purpose of this lab was to find how the distance of a light source from a plant
would affect the rate of photosynthesis. In the lab, the independent variable, or the
distance of the light source, affected the dependent variable, or the rate of
photosynthesis; when the light source was farther, the photosynthesis would decrease
due to the decreased intensity of heat and light. Whereas if the light source was closer,
the intensity would increase, thus increasing photosynthesis (refer to graph for
reference).

The hypothesis of the lab was if the Elodea is placed farther from the light source, then
it would lower the rate of photosynthesis. The hypothesis was supported because when
the light was closest (25 cm above the plant), the bubble count was 39. When the light
source was raised to 31 cm from the plant, the rate went down to 21. When the lamp
was raised to 45 cm, a count of 19 bubbles was recorded.
Conclusion: Part 2

The control recorded outside in the sun offered a count of 28 bubbles. The bubble count
indicated the rate of photosynthesis; if there was a higher count that meant that there
was a higher rate of photosynthesis. As the results showed, when the light source was
the closest the count was the highest. That proved the hypothesis correct.

In the experiment, there were some procedural errors that may have affected the data.
One of those errors was the possibility of recounting the same bubble. In the 3rd run of
the first trial, the lamp was crooked and may have not focused the full beam intensity. If
the lamp had not been crooked, the results may have changed. The largest error was the
fact that not all of the trials were finished. Only trial 1 was recorded due to the fact that
there wasn’t enough time to do a total of 15 minutes of counting for 3 trials.
Conclusion: Part 3

This lab may change if the light source is more natural, like the sun at different times of
day. It would most likely extend to only 1 trial a day, as you would have to count at
sunrise, noon and sunset. But the results may be more reliable. This lab would affect the
real world for plant growers and harvesters. If farmers put their plants closer to the
light, photosynthesis would increase, as the experiment results show.
Bibliography

Aquatic Biologists (2014) Weed Info-Elodea (Canadian Water Weed)


Rader, Andrew (2014) Photosynthesis


Retrieved from http://www.biology4kids.com/files/plants_photosynthesis.html
Pearson (2014) An Overview of Photosynthesis


Retrieved from https://www.aquaticbiologists.com/algae--weed-id-guide/submergedweeds/elodea-(canadian-water-weed)
Retrieved from
http://www.phschool.com/science/biology_place/biocoach/photosynth/overview.html
Swistock, Bryan (2014) Elodea (Common Waterweed)

Retrieved from http://extension.psu.edu/natural-resources/water/ponds/pondmanagement/aquatic-plants/elodea-common-waterweed
Photosynthesis and
Elodea
By Matthew Abolafia
Abstract

Abstract
This lab is about Elodea and photosynthesis, and how the
distance of a light source affects the rate of photosynthesis. The
lab may influence plant growers to place their plants closer to a
light source, to increase the rate of photosynthesis. The
experiment proved that if the light source was too far away,
photosynthesis would be slower and less productive.
The procedure was to place Elodea under heat lamps and count
the bubbles of photosynthesis in test tubes. A higher count of
bubbles showed a higher rate of photosynthesis. The variables
were photosynthesis and the distance of the light source. The
results were recorded for 1 trial.
When the lamp was closest to the Elodea, the amount of bubbles
of photosynthesis was 39, a fast rate of photosynthesis. As the
lamp rose in height, the number of bubbles dropped, showing
slower rates of photosynthesis This experiment could influence
botanists who produce Elodea by helping to increase their
harvest rates.
Research: Part 1: Photosynthesis

Photosynthesis is a cycle gone through by plants to convert light into chemical energy for later use.
Photosynthesis starts in chloroplasts, which are a part of the plant. The chloroplasts capture chlorophyll,
an important chemical needed for photosynthesis. Chloroplasts also capture water, carbon dioxide,
oxygen and glucose. The chlorophyll is taken to the stroma, another part of the plant. In the stroma the
carbon dioxide and water blend together to make oxygen and glucose. The oxygen keeps all species on
earth alive because animal cells need an aerobic environment, or air filled environment to survive. The
glucose produced by the chloroplasts is used in many ways by different animals. Glucose is absorbed into
the animals’ bloodstream where it is used as a nutrient. Photosynthesis does not happen all at one time,
photosynthesis is divided into two important sections. The first is light-independent reactions. These
reactions happen when light energy is captured and made into a chemical known as Adenosine
triphosphate, or ATP. ATP is an enzyme used for reproduction, in a more modern term ATP is the
molecular unit of currency for reproduction. The second step of the process occurs when ATP is used to
create glucose, this is the light dependent reaction (Rader, 1997).

Photosynthesis takes electrons from water to energy-lacking carbon dioxide molecules, forming energetic
sugar molecules. This movement of electrons is an example of an oxidation reduction process. “The water
loses electrons and becomes oxidized,” (Pearson, 2014). Then, the oxidized water is taken to a different
species. Photosynthesis uses light energy to transfer electrons from water to more energetic states in sugar
molecules, therefore changing solar energy to chemical energy (Pearson, 2014).
Research: Part 2: Elodea

Elodea is also called: American elodea, common elodea, anacharis and Canada
waterweed (Aquatic Biologists, 2014). Elodea can grow in heights between 4 inches to
3 feet, depending on the depth of the body of water. Elodea is an underwater marine
plant with oval shaped leaves grouped into clusters of 3 or 4 around the stem that
provides shelter for fish and other sea organisms, and is an excellent producer of much
needed oxygen. Elodea is a food for geese and ducks, who feed on the fruit produced by
Elodea. Elodea reproduces by growing large buds in the springtime, relying very little
on seed reproduction. Because Elodea relies on a fragmenting process of breaking off
stem particles that sink to the ground and grow a new plant. But along with its
advantages, Elodea has some disadvantages. If populations of Elodea become overly
crowded, Elodea can reduce water temperatures, which can disturb sea life and possibly
kill them. Dense growth can become a poorer habitat for fish. Elodea is a common
aquarium plant, but even though it is very common, most people don’t know its name.
Its common name is “that aquarium plant.”(Rader, 1997; Swistock 2014). Elodea grows
in pond habitats and prospers in the fine sediment at the bottom of cool, spring-fed
ponds. Elodea is one of the few pond plants that can remain green throughout the cold
winter season.” (Swistock, 2014).
Question and Hypothesis

Question

\

Hypothesis
Does the distance of a light source from an Elodea plant affect the rate of
photosynthesis?

If the light source is closer to the plant, then the rate of
photosynthesis will be faster, because the light is closer and
more intense.
Variables and Materials

Variables

Materials
The independent variable was the distance of the light source
from the plant. The dependent variable was the rate of
photosynthesis of the Elodea plant.
Elodea (15.24 cm stem)
3 stems
Distilled Water
50 ml
500 ml Beaker
1
Heat Lamp
3
Test Tubes and Rack
1 Rack, 3 Test Tubes
Tape and Marker
1 of each
Goggles
1
Ruler (30.44 cm)
1
Scissors
1
Procedures
1. Put on necessary safety items (apron and goggles)
2. Obtain materials and label test tubes T1, T2, T3, and Ctrl

Procedures
3. Pour 50 ml of water in a single test tube
4. Place 15.24 cm Elodea in a single test tube and place test tube
on rack
5. Adjust heat lamps to heights of 25 cm, 31 cm, and 45 cm.
6. Place test tube rack under heat lamp of height indicated for
that trial
7. Turn lamp on and carefully count bubbles on Elodea stem for
5 minutes
8. Repeat steps 3-8 for trials 2 and 3
9. For Ctrl, time for five minutes outdoors in the sun
10. Record results in journal
Results
50
45
40
Lamp Height (cm) Bubbles counted
35
25
39
30
31
21
25
45
19
20
15
10
5
0
1
2
Lamp Height (cm)
3
Bubbles counted
Conclusion: Part 1

The purpose of this lab was to find how the distance of a light source from a plant
would affect the rate of photosynthesis. In the lab, the independent variable, or the
distance of the light source, affected the dependent variable, or the rate of
photosynthesis; when the light source was farther, the photosynthesis would decrease
due to the decreased intensity of heat and light. Whereas if the light source was closer,
the intensity would increase, thus increasing photosynthesis (refer to graph for
reference).

The hypothesis of the lab was if the Elodea is placed farther from the light source, then
it would lower the rate of photosynthesis. The hypothesis was supported because when
the light was closest (25 cm above the plant), the bubble count was 39. When the light
source was raised to 31 cm from the plant, the rate went down to 21. When the lamp
was raised to 45 cm, a count of 19 bubbles was recorded.
Conclusion: Part 2

The control recorded outside in the sun offered a count of 28 bubbles. The bubble count
indicated the rate of photosynthesis; if there was a higher count that meant that there
was a higher rate of photosynthesis. As the results showed, when the light source was
the closest the count was the highest. That proved the hypothesis correct.

In the experiment, there were some procedural errors that may have affected the data.
One of those errors was the possibility of recounting the same bubble. In the 3rd run of
the first trial, the lamp was crooked and may have not focused the full beam intensity. If
the lamp had not been crooked, the results may have changed. The largest error was the
fact that not all of the trials were finished. Only trial 1 was recorded due to the fact that
there wasn’t enough time to do a total of 15 minutes of counting for 3 trials.
Conclusion: Part 3

This lab may change if the light source is more natural, like the sun at different times of
day. It would most likely extend to only 1 trial a day, as you would have to count at
sunrise, noon and sunset. But the results may be more reliable. This lab would affect the
real world for plant growers and harvesters. If farmers put their plants closer to the
light, photosynthesis would increase, as the experiment results show.
Bibliography

Aquatic Biologists (2014) Weed Info-Elodea (Canadian Water Weed)


Rader, Andrew (2014) Photosynthesis


Retrieved from http://www.biology4kids.com/files/plants_photosynthesis.html
Pearson (2014) An Overview of Photosynthesis


Retrieved from https://www.aquaticbiologists.com/algae--weed-id-guide/submergedweeds/elodea-(canadian-water-weed)
Retrieved from
http://www.phschool.com/science/biology_place/biocoach/photosynth/overview.html
Swistock, Bryan (2014) Elodea (Common Waterweed)

Retrieved from http://extension.psu.edu/natural-resources/water/ponds/pondmanagement/aquatic-plants/elodea-common-waterweed
ELODEA SCIENCE FAIR
PROJECT
By Ryan Roulette
QUESTION
Does the distance from the light effect the rate of photosynthesis.
VARIABLES
The independent variable is the distance from the light source, the dependent
variable is the rate of photosynthesis and the constant is the time the elodea is
exposed to the light.
HYPOTHESIS
If the elodea is closer to the light, then the rate of photosynthesis will be faster
because plants need light to photosynthesize.
MATERIALS
Material
Amount (SI Units)
Test tube
3
Water
90 millilers
elodea
30 centimeters
Heat lamp
1
Lamp stand
1
PROCEDURES
1. Gather
DATA
Science Fair
BY: SAM STRINGER
Question
Does the distance of the light
source affect the rate of
photosynthesis in the elodea plant?
Variables
The Independent Variable in this
experiment is the distance the light
source is from the elodea plant.
The Dependent Variable is the
rate that the photosynthesis occurs.
Purpose
The purpose of the lab was to
find out if the distance that light
travels affects the rate of
photosynthesis.
Hypothesis
If the light source is further away
from the elodea plant then the
affect will be less powerful and will
cause less photosynthesis to occur
in the plant, because the further
the light is the more distance the
light has to travel and that will
cause the light to be less effective.
Materials
Material
Lamp
Elodea
125ml Flask
Test Tube
Ruler
Distilled Water
Stop Watch
Goggles
Apron
Amount
1
45cm
1
1
1
900ml
1
1
1
Procedures

Wear safety goggles and apron at all times when around any glass objects or chemicals.

Gather all materials. (Refer to materials list)

Go to a dark area in the testing place.

Put 400ml of water into your testing flask.

Use scissors and a ruler to cut a piece of elodea plant to be 5cm long.

Place that piece of elodea into the water filled flask.

Put test tube with open end into the flask on top of the elodea.

Prepare your lamp for the testing.

Place flask 10cm away from the lamp then turn it on and start stopwatch and stop in 3.5 minutes.

Count bubbles and record.

Repeat steps 3 -10 two more times for trial 1.

Each trial move the flask 5cm further away from the lamp.

Record and graph all results.
Logging

Sep. 17 - Wrote the question / Started lab report

Sep. 20 - Formulated hypothesis

Sep. 25 - Made materials list

Oct. 4 - Started procedures

Oct. 6 - Wrote research paper on photosynthesis

Oct. 7 - Started testing

Oct. 10 - Graphed all data

Oct. 12 - Wrote conclusion

Oct. 17 – Wrote abstract
Data
Results
6
Bubbles
Counted
5
4
3
2
1
0
Trial 1
Trial 2
10cm
15cm
Trial 3
20cm
Research Essay on Photosynthesis
Photosynthesis is a process that a plant goes through to turn light energy into sugars that give the plant the
nutrients it needs. “It occurs whenever plants are exposed to the sun”. The light energy that it takes in is normally sun
light. This process is vital for a plant to be able to live. All of a plant’s activities throughout the day take a lot of energy,
which is given to it by photosynthesis.
Photosynthesis was discovered by Jan Van Helmont in the 1600s. “Later Theodor Engelmann figured out that this
occurred in chloroplast.” Chloroplast is an organ in a plant cell that contains chlorophyll. He found this when he
experimented by weighing a tree with the soil and then he planted the tree. After 5 years he weighed the tree again
and the tree weighed more and grew taller, but the soil’s weight was about the same. This meant that the tree was
not taking any of the soil as energy and it had an alternate source of energy. Then he realized that he had been
giving the tree water, so it must have been getting the energy from that. He was partially right. The tree needs water,
light and carbon dioxide to live and get nutrients.
Photosynthesis mostly takes place in the leaves of a plant. The sun light enters through the pores of the leaf
called stomata. The chlorophyll inside of the chloroplast is what absorbs the sunlight. Then the chlorophyll forms
antenna complexes, which are a complex of protein molecules. This transfers light into different photo chemicals,
which then turn into energy. This process is what keeps plants alive today. When a plant lives inside of a house
someone needs to water it and it has to have sunlight for these reasons. If you put a plant in the back of a closet and
didn’t give it water at any time it would die.
There are many ways to measure if an elodea plant is photosynthesizing. ”Elodea is sometimes confused with
Hydrilla and Egeria”. One example is to get a twig with elodea on it and remove all leaves from around the twig.
Place the elodea into a test tube with the stem facing upward and fill the tube with water then place the test tube on
the test tube rack. Place a 40 watt light bulb 5 cm under the plant. After one minute has passed count the number of
bubbles in the test tube and record your results.
In conclusion, photosynthesis is a vital part of the plants life. Photosynthesis provides the plant with nutrients and
energy that it needs to live. Photosynthesis is a short and productive process the plant does without any hesitation. This
is somewhat like the human body breathing. We never have to think about doing this.
Works Cited

Gregory, M. (n.d.). Photosynthesis. Retrieved from
http://faculty.clintoncc.suny.edu/faculty/michael.gregory/files/bio
101/bio 101 laboratory/photosynthesis/photosynthesis.htm

Elodea. (n.d.). Retrieved from http://aquaplant.tamu.edu/plantidentification/alphabetical-index/elodea/

Photosynthesis History. (n.d.). Retrieved from
http://www.shmoop.com/photosynthesis/history.html
Conclusion
The purpose of the lab was to find out if distance affects how fast photosynthesis
occurs. The independent variable was the distance away the lamp was from the
elodea. The dependent variable was the rate of the photosynthesis. The relationship
between them was that the distance of the light will affect the rate of the
photosynthesis. The hypothesis is that the further away the light got the less
photosynthesis would occur in the flask. This was supported by the results that we got
during the lab. They show that the further away the light got the less powerful the light
became. This means the further the light traveled the energy became weaker. The
procedural error that ended up being fixed was that the trials weren’t totally finished.
The investigations that could be based off of this project could be instead of changing
the distance of the light you could change the light bulb wattage. This project could
help the people who work with agriculture.
Abstract
The purpose of the lab was to find out if the distance of the light source would
affect the rate of the photosynthesis. The bubbles that rise would show use how
much photosynthesis was occurring at the specific distance. The hypothesis was
the father away the light got the less photosynthesis would occur.
First the Elodea would be cut to be 5cm long. The Elodea was then placed in
the glass flask. The flask was 100ml full of water. The lights where then turned on and
we saw the bubbles raise to the top of the water. Then the steps were repeated
the steps over and over until we got enough to record the data.
In conclusion the results showed that the father away the light got the less
photosynthesis occurred. This shows that the light energy is less affective when it is
further away. It also shows that the distance makes the energy slowly deteriorate
over time. The hypothesis that was stated at the beginning of the project was
proven and the reasons for this prediction were also proven correct.
Photosynthesis lab
Purpose
• Does the distance of the light source affect the rate of
photosynthesis.
Hypothesis
• If the distance of the light source increases then the rate of
photosynthesis will decrease because the light source is farther
away.
variables
• Independent variable the distance of the light source
• Dependent variable rate of photosynthesis
Materials
•
•
•
•
•
•
4 6 cm live elodea samples
1 heat lamp
500 ml of distilled water
Safety goggles (1 or more)
3-4 125 ml flasks
Journal (1 or more)
procedures
•
•
•
•
•
•
•
•
•
•
•
1. Put on safety goggles and gather materials (see materials list.)
2. label and fill each 125 ml flask with distilled water.
3. Place each live elodea sample in each 125 ml flask of distilled water make sure completely submerged.
4. Take the first elodea sample and put it 10 cm away from heat lamp (turn on high.)
5. Count how many bubbles appear on the plant count for 3 min.
6. record results.
7. Remove sample 1 away from the heat lamp and put sample 2 20 cm away from the heat lamp.
8. repeat 5-6.
9. remove sample 2 away from heat lamp and place sample 3 30 cm away from the heat lamp.
10. repeat 5-6.
11. calculate results in journal.
Data table
• Trial 1: 1, 0, 13
• Trial 2: 2, 2, 19
• Trial 3: 3, 14, 29
Graph
Rate of photosynthesis
30
25
20
trial 1
15
trial 2
trial 3
10
5
0
trail 1
trial 2
trial 3
conclusion
•
•
•
•
•
Relationship between variables- when the distance of the light source
(independent variable) increased the rate of photosynthesis (dependent variable)
increased.
Hypothesis- the hypothesis stated “If the distance of the light source increases
then the rate of photosynthesis will decrease” this was incorrect the data proves
that when the distance of the light source increased the rate of photosynthesis
also increased.
Explanation of results- trial 1 the light source was 10 cm away from the elodea the
average bubbles that appeared was 2. trial 2 the light source was 20 cm away from
the elodea with an average of 5 bubbles. Trial 3 the light source was 30 cm away
from the elodea with an average of 3 bubbles.
Procedural errors- while counting the bubbles the flask containing the elodea was
turned and some bubbles might have been counted twice. This resulted
inconclusive data. If the elodea was not turned then it would have led to more
precise data.
Further investigation- the independent variable could have been changed by
instead of the distance of the light source it could be measured by the length of
the elodea plant.
Elodea Lab
Shy’La and Kaliyah
7th Period
Purpose
The purpose of the lab was to
figure out if the distance of light
source changed, would if affect the
rate photosynthesis occurs at.
Hypothesis
If the distance of light source is further
away, then the rate of photosynthesis will
decrease, because then it will be less light
and less light in the chloroplasts means less
photosynthesis.
Procedures
•
•
•
•
1.
2.
3.
4.
• 5.
• 6.
• 7.
Safety is priority. Put on apron and safety goggles.
Gather materials.
Place 10 cm elodea plant in 30 mL of distilled water.
Arrange light sources at points 10cm, 20cm, and 30cm pointing
towards the elodea plants with y being the control.
Throughout 2 minutes time of testing, record how many bubbles
appear in each test tube.
Record results in notebook.
Repeat steps 1-6 2 times
Abstract
The purpose of the project was to figure out if the distance of light source had an affect on the rate
of photosynthesis of an Elodea Plant. The hypothesis stated that if the source of light is further away,
then the rate of photosynthesis will decrease because there will be less light and less light in the
chloroplasts means less photosynthesis.
Before starting the lab, safety is top priority. We put on goggles and aprons. After that, we gather our
materials. Then, place 10 cm elodea plant in 30 mL of distilled water. Then, Arrange light sources at
points 10cm, 20cm, and 30cm pointing towards the elodea plants with y being the control. After that,
Throughout 2 minutes time of testing, record how many bubbles appear in each test tube. Finally, record
results in notebook and repeat steps 1-6 for trials 2 and 3.
In this lab, we witnessed photosynthesis occur in an Elodea plant. To see this process happening, we
noticed that as the light distance changed, in some trials, our hypothesis was supported. Meaning that it
decreased in some trials, but in some other trials, the bubbles increased. This showed that plants need light
in order for photosynthesis to occur.
Data
Trials 10cm 20cm 30cm
Control
1
14
16
9
10
2
12
13
10
11
3
14
11
13
15
Graph
Y
Photosynthesis and Elodea Lab
10cm
Amt. Of Bubbles
18
16
14
12
10
8
6
4
2
0
Trial 1
Trial 2
Trials
Trial 3
20cm
30cm
Control
X
Conclusion
The hypothesis stated that if the source of light is further away, then the rate of
photosynthesis will decrease, because there will be less light and less light in the chloroplasts
means less photosynthesis. The hypothesis was supported, although in some trials the bubbles
increased.
To get more precise data, all the leave should’ve been removed. One of the Elodea plants
had no leaves at all, which could’ve been resulted in counting more bubbles. If all the leaves
would’ve been removed, more bubbles would’ve been shown, and the data would have shown
more increase rather than more decrease.
In trial 1, the bubbles increased by 14, then by 2, and decreased suddenly by 7. Afterwards,
trial 2 showed that 12 bubbles were recorded, then 13, and ended with 10. Finally, in trial 3 the
experiment concluded with 14 bubbles, decreasing by 3, and then by 2 more.
Depending on the distance and
how frequent oxygen circulates,
does the process of
photosynthesis change?
Science fair 2014-2015
Question
• Depending on the distance and how frequent oxygen circulates, does
the process of photosynthesis change?
Hypothesis
• If the light source is closer to plant, then the rate of photosynthesis
would increase, because the light source is closer to the plant.
Variables
• The dependent variable was the rate of photosynthesis, which was
measured by counting oxygen bubbles that came from the Endola
plants.
• The independent variable was the distance of the light source.
• The control group in this experiment was the plants with no light.
• One constant in this experiment was the light source. Although the
distance was raised each time, the light source itself remained the
same.
Materials List
• One Lamp, it should be at least 15 cm tall and make sure you can adjust the bulb’s height.
• One lamp clamp, this is to adjust the height of the bulb.
• One lamp holder, this is to hold your lamp in place.
• Goggles, you should have goggles for each person working on the experiment.
• One test tube holder. The holder should hold at least nine test tubes.
• Test tubes, the test tubes need to be big enough to hold 20 mL of spring water and a 5 cm plant. Depending on how many trials, more test
tubes will be needed. As with any scientific experiment, be sure to label the test tubes.
• One 250 mL beaker. This will hold the spring water until it is needed.
• One graduated cylinder. Just in case the beaker isn’t enough, you can also use this to hold water. A 300 milliliter-graduated cylinder should
do the trick.
• One plastic funnel. Use this to pour water into the test tubes. This also prevents accidental spilling.
• One pair of scissors, use the scissors to cut stocks to their proper sizes.
•
Endola plant samples, the samples should be cut down to 5 cm stalks without leaves. Depending on how many trials planned, three for
each trial is standard. For three trials, nine samples will be needed.
• For each sample, use 20 mL of spring water.
Procedures
1)
Above all, always use safe practices. When using the electrical equipment in this experiment, be careful.
2)
Collect all the materials needed, see previous slide for details.
3)
Using the lamp clamp, raise or lower the lamp to 5 cm.
4)
Place the Endola plant sample in the test tube. The samples should be 5 cm long and also have the leaves taken off. Pour 10
milliliters of spring water in the test tube, then place the test tube in the test tube holder.
5)
Place the test tube holder under the lamp for 3 min.
6)
Record how many bubbles are in the test tube.
7)
Repeat this two more times with a different sample and a different test tube. Don’t change the height of the lamp.
8)
Raise the lamp to 10 cm. Get three different samples.
9)
Follow steps four through seven, changing the test tubes and the samples as needed. Change the samples for each trial.
10)
Raise the lamp to 15 cm.
11)
Follow steps four through seven, changing test tubes and samples as needed.
12)
Be sure to record all of the data.
Data table (in number of bubbles)
Height of Lamp (in
centimeters)
5 cm
10 cm
15 cm
1st Trial
5
7
8
2nd Trial
12
8
9
3rd Trial
11
8
8
Control – No Light
6
N.D.
N.D.
2nd Time
3rd Time
Control
8
1st Time
8
8
8
9
THE EFFECT THAT DISTANCE OF THE LIGHT SOURCE HAS ON
PHOTOSYNTHESIS
7
BUBBLES COUNTED (RATE OF PHOTOSYNTHESIS
Graph
10 CM
15 CM
DISTANCE OF THE LIGHT IN CM
Purpose of the Lab
• The purpose of this lab was to find out more about photosynthesis.
• Another purpose was to figure out which distance, 5 cm, 10 cm or 15
cm the Endola oxidizes best in.
Hypothesis Restated
• If the light source is closer to the plant, then the rate of
photosynthesis would increase, because the light source is closer to
the plant. This was supported by the fact that in the second and third
trial when the lamp was at 5 cm, 11 and 12 bubbles were counted,
respectively.
Relationship between Variables
• The dependent variable was the number of bubbles counted. The
independent variable was the height of the lamp in centimeters. At 15
cm, the lamp was furthest from the plant. The farther the lamp was
the less, on average, number of bubbles were counted. At 5 cm, the
lamp was closest to the plant. Thus, the most bubbles, on average,
were counted. This means that the closer the lamp was, the more
bubbles were counted. The distance of the lamp affected the number
of bubbles counted.
Explanation of results
• As mentioned previously, the lamp at 5 cm had the fastest rate of
photosynthesis. Surprisingly, the lamp at 15 cm had the second
fastest rate of photosynthesis. The lamp at 10 cm had the slowest
rate Recall that the rate of photosynthesis was determined by how
many bubbles were counted. The first trial at 5 cm had five bubbles
counted, at 10 cm, seven bubbles were counted. At 15 cm for the first
trial eight bubbles were counted. For the second trial, at 5 cm, 12
bubbles were counted, at 10 cm, eight bubbles were counted, at 15
cm, nine bubbles were counted. The third and final trial had 11
bubbles counted at 5 cm, at 10 cm, eight bubble were counted, this is
the same for 15 cm as well. The control with no light had six bubbles
counted.
Procedural errors
• Since a time limit to do this experiment was in place, more time to
record as the lamp was being raised would have been favored.
Further investigations
• Changing the type of plant would be a nice way to extend the life of
this experiment. Different plants might have different rates and it
would be fun to compare the different rates.
Real-world Application
• If a person goes off in a spaceship, they might need extra oxygen. One
might use this experiment to do so.
Elodea Undergoing
Photosynthesis Underwater?
BY: LEAH HENRY AND ADRIELLE LANGSTON
PURPOSE
Is the Rate of Photosynthesis affected by the
light source?
HYPOTHESIS
If the light source is closer then the rate of
photosynthesis will increase because plants use green
pigments called chlorophylls that trap light energy to produce
glucose, called photosynthesis, so, if the light source is closer
the plant will be able to trap more light energy an make more
photosynthesis.
VARIABLES
• Independent Variable- The Distance of Light
• Dependent Variable- The Rate of Photosynthesis
MATERIALS
Elodea
Goggles
Distilled Water
Timer/Watch
Small Metal Lamp
Test Tubes
Scissors
Measuring cup
Test Tube Stand
1(10cm)
4 Pairs
125ml
1
1
3
1
1
1
PROCEDURES
1.
Safety; wear goggles for eye protection, and be careful with/of hot objects.
2.
Label test tubes Trial 1,2, and 3.
3.
Cut elodea to 10cm.
4.
Take leaves off of elodea carefully with scissors.
5.
Fill beaker to 125ml with distilled water and pour gently in test tube(Trial 1).
6.
Gently place elodea in the test tube (Trial 1) filled with the distilled water.
7.
Make ring stand and gently place lamp in/on it.
8.
Mark points on lamp at 10cm, 20cm, and 30cm.
9.
Place test tube in the test tube(Trial 1) stand carefully.
10.
Repeat steps 3-9 but with Trial 2 and 3.
11.
Place lamp at 10cm.
12.
Turn the lamp on.
13.
After 3 minutes turn light off.
14.
Record how many bubbles were on each plant.
15.
Repeat steps 9-13 but put the lamp at 10cm and 20cm.
30cm
10cm
ABSTRACT
The purpose of this lab was to decide if the rate of photosynthesis is effected by the light source. We wanted to
find this out because plants do grow underwater but, do they go through photosynthesis while there in the water? If the light
source is closer then, the rate of photosynthesis will increase because plants use green pigment’s called chlorophylls to trap
energy to produce glucose, so, if the light source is closer the plant can trap more energy and make more photosynthesis.
This will make sure that if you have this plant and its growing to fast and you think it will die then you know to just move it
farther away.
To analyze this purpose we labeled three test tubes trial one, two, and three. After we labeled you ten cut the
elodeas to 10cm then, take the leaves of them carefully with scissors, and once you have done that to all three fill the
beakers to 125ml with distilled water and pour into test tube and then, gently place elodea in the test tube. After all that is
set up now it’s time to set up the rest and then get started. Make the ring stand and gently place lamp in/on it then mark
points on lamp at 10cm, 20cm, and at 30cm. Then, place test tube 1, 2, and 3 under the lamp and put the lamp at 10cm then,
turn the light on. After 3 minutes turn the light off and record how many bubbles came up. Now repeat steps 9-13 but put
the lamp at 20cm and 30cm and record the results of how many bubbles there were.
The purpose of this lab was to determine if the distance of light will affect the rate of photosynthesis which it did.
The hypothesis stated that “If the light source is closer than the rate of photosynthesis will increase because plants use green
pigment’s called chlorophylls to trap light energy to produce glucose, called photosynthesis, so if the light source is closer it
will be able to trap more energy and make more photosynthesis” This hypothesis was not supported because the results had
shown that when the light was closer there were less bubble which means not as much photosynthesis going on. In this
observation the objective was met because we did get our question answered.
DATA
# of Bubbles at 10cm
# of Bubbles at 20cm
# of Bubbles at 30cm
Trial 1
0
7
15
Trial 2
2
2
3
Trial 3
11
20
13
Control
0
0
0
GRAPH
ELODEA RESULTS
AMOUNT OF BUBBLES/RATE OF PHOTOSYNTHESIS
y
25
20
20
15
15
13
# of Bubbles at 10cm
11
# of Bubbles at 20cm
10
#of Bubbles at 30cm
7
5
2
0
2
3
0
0
Tral 1
Trial 2
Trial 3
TRIALS
0
Control
0
x
CONCLUSION
The light source (independent variable) causes the rate of photosynthesis to vary for each trial. As the distance increased, so did the rate of
photosynthesis, so when the light source was lower, so was the rate of photosynthesis.
The purpose of the lab is to determine if the distance of the light will effect the rate of photosynthesis.
The hypothesis stated ‘ The light source is closer, then the rate of photosynthesis will increase because plants use green pigments called
chlorophylls that trap light energy to produce glucose, called photosynthesis so if the light source is closer, it will be able to trap more energy and
make more glucose. This hypothesis was not supported because when it was closer, the rate of photosynthesis was lower.
The results were found by counting bubbles. The results were inconsistent because trial 1 had 0 bubbles at 10 centimeters, 7 bubbles at 20 cm,
and 15 bubbles at 30 cm. Trial 2 had 2 bubbles at 10 cm, 2 bubbles, at 20 cm, and 3 bubbles at 30 cm. Trial 3 had 11 bubbles at 10 cm, 20
bubbles at 20 cm, and 13 bubbles at 30 cm.
A procedural error that occurred was that the leaves on the elodea were not cut for trial 2 and trial 3. By going back and doing it again there may
have been more accurate results. Another procedural error was miscounting bubbles. Maybe by having more people counting, the results might
have been different.
Instead of using regular lights, use LED lights like red, blue, green, and purple to determine which grows faster.
This could be used for plant companies for making their plant thicker or thinner for water glasses/pots, so the plants can grow bigger and better.