Explore Teacher Guide
Standards (3)
7.5A7.3B(i)7.4A(xxxi)Description
In this activity, students will use plastic chips to model and recognize that radiant energy from the Sun is
transformed into chemical energy through the process of photosynthesis.
Material
Printed Material
Student reference sheet: Photosynthesis (1 per group)
Explore Student Guide (1 per group)
Explore Student Journal (1 per student)
Reusable
18 Plastic chips, one color (per group)
12 Plastic chips, second color (per group)
6 Plastic chips, third color (per group)
1 Plastic, bag, zip top, sandwich (per group)
1 Marker, permanent (per teacher)
Consumable
None
Preparation
Print one student reference sheet: Photosynthesis in color for each group in your class. Laminate for
repeated use. Print one Explore Student Guide for each group and one Explore Student Journal for each
student in your class.
Use a permanent marker to write the letter “O” on both sides of the 18 plastic chips of one color. Write
the letter “H” on both sides of the 12 plastic chips of the second color. Write the letter “C” on both sides
of the 6 plastic chips of the third color. Create sets of chips for each group by placing the groups of 18,
12, and 6 chips of three colors into a plastic zip bag.
Plastic poker-playing chips work well for this activity.
STEMcoach in Action
Your students will be learning cooperatively about photosynthesis. Gain more information about using
cooperative groups in your classroom so that you may hold students individually accountable, and allow
them to have face-to-face academic interaction with peers.
Background
Student Guide
Read together as a class or have students read aloud to each other.
The word photosynthesis can be broken down to its Greek origin: synthesis put together to form
something new; and photo light. So the Greek origin of the word photosynthesis means put together to
form something new from light. This amazing process of forming something new from light,
photosynthesis, is what sustains life on Earth.
The most important aspect of photosynthesis is that radiant energy (from the Sun) transforms to
chemical energy. The chemical energy is stored in the plant as sugar and is available as food. The leaves
of plants contain everything needed to absorb the rays of the Sun and start photosynthesis. This
interaction between radiant energy from the Sun and matter (carbon dioxide and water) causes a
chemical reaction with the result of the formation of different matter (sugar and oxygen). The radiant
energy absorbed by the plant is transformed during the process of photosynthesis and is stored within
the newly formed sugar as chemical energy in the plant. Fortunately for us, oxygen is also released to
the atmosphere during this process.
How a plant actually accomplishes this transformation is still a mystery as scientists are not able to
recreate the natural process of photosynthesis using man made materials. However, what happens to
the beginning substances (the reactants) and resulting substances (the products) during photosynthesis
is understood, can be measured, and can be easily represented using models.
In this activity you model the process of photosynthesis to see what happens to elements and
compounds of the reactants and products as radiant energy is transformed to chemical energy. Answer
the background questions in the Explore Student Journal and then begin Part I.
Student Journal
1. What interaction between matter and energy occurs during the process of photosynthesis?
During the process of photosynthesis, radiant energy from the Sun interacts with matter found in plants,
carbon dioxide, and water in a chemical reaction that results in the transformation of radiant energy
into chemical energy and the formation of different matter, sugar, and oxygen.
2. How does radiant energy become food for a plant?
Radiant energy from the Sun is absorbed by the leaves of a plant. The radiant energy is transformed by
the process of photosynthesis to chemical energy, which is stored in the plant as sugar.
3. Put the meaning of the Greek origin words synthesis and photo together to explain the meaning
of the word photosynthesis.
Photosynthesis means to make something from light.
Facilitation
Collect and Analyze Data with Life Science Models
Life science models are used to collect information when concrete data is obtained. In this activity,
students use models of photosynthesis to collect information on the different reactants and products
associated with this process.
Life science models are used to analyze information when models are compared, used to demonstrate
processes, or when used as part of a design process. In this activity, students make a model of
photosynthesis to analyze how the reactants cause photosynthesis to occur. They also use this life
science model to analyze how radiant energy play a part in this process.
Make sure students understand how to use a life science models properly in the classroom laboratory
and refer to the Process Skills Primer in the Teacher Toolbox for more information on all Science Tools.
Part I: The Reactants
Student Guide
The reactants must be present and available to the plant for photosynthesis to occur. Carbon dioxide is
in the atmosphere and enters the plant through structures in the leaf called stomata. Water is absorbed
by the plants roots.
Distribute the *Reactants of Photosynthesis* page.
1. Obtain 12 plastic chips labeled H, 6 plastic chips labeled C, and 18 plastic chips labeled O and the
reactants page of photosynthesis.
2. The plastic chips represent atoms of hydrogen, carbon, and oxygen.
3. Use these atom models to build and represent water and carbon dioxide on the Reactant of
Photosynthesis page. Place a stack of atom chips on each circle to represent the substance.
4. Answer the questions for Part I in the Explore Student Journal.
Monitor students to ensure they place chip stacks, on the indicated substances, in the correct ratios.
Carbon dioxide needs two chips labeled “O” and one chip labeled “C.” Water needs two chips labeled
“H” and one chip labeled “O.” Lead the students in a discussion about what the labeled chips represent
in the model. Discuss that the atoms are matter. Ask students to identify the source of the energy (the
radiant energy is from the Sun, which is pictured on the paper model), and challenge students to look
for how the matter interacts with energy during the process of photosynthesis.
Student Journal
1. How many hydrogen atoms in total appear as any part of the reactants?
12
2. How many carbon atoms in total appear as any part of the reactants?
6
3. How many oxygen atoms in total appear as any part of the reactants?
18
4. What is the source of the carbon dioxide as a reactant in photosynthesis?
The atmosphere.
5. How does carbon dioxide enter the plant?
Through the stomata of the leaf
6. What is the source of water as a reactant in photosynthesis?
The soil
7. How does the water enter the plant?
The roots absorb the water from the soil.
Part II: Energy Transformation
Student Guide
Leaves absorb radiant energy from the Sun and can be thought of as a solar energy collectors. A leaf
contains a pigment called chlorophyll. Chlorophyll gives a plant its green color and takes part in the
action of transforming radiant energy to chemical energy. During photosynthesis, chlorophyll absorbs
radiant energy and transforms it to chemical energy when water and carbon dioxide react. The reaction
produces combinations of atoms with usable chemical energy stored within these newly formed
substances of sugar and oxygen.
Distribute the *Energy Transformation through Photosynthesis* page.
1. Place your Energy Transformation through Photosynthesis page directly to the right of the
Reactants page.
2. Sweep all of the atoms of the reactants into one big messy pile on the energy transformation
arrow.
Monitor students to see they create a big messy pile of unstacked chips on the energy transformation
arrow. Ask students what interaction occurs between matter and energy at this stage of the model.
They should note that the radiant energy from the Sun has been absorbed into the chlorophyll in the
leaves. This is where the energy interacts with the matter found in the leaves, carbon dioxide, and water
to begin a chemical reaction.
3. Answer questions for Part II in the Explore Student Journal.
Student Journal
1. What acts as the radiant energy collector in a plant?
Leaves
2. What part does chlorophyll play in the photosynthesis process?
The pigment, chlorophyll, absorbs radiant energy and takes part in the action of transforming radiant
energy to chemical energy.
3. After the transformation from radiant energy, where is the chemical energy stored?
Within the newly formed substances of sugar and oxygen
Part III: The Products
Student Guide
The sugar formed as a result of photosynthesis is called glucose. The product glucose is a larger
molecule than either of the reactants, water and carbon dioxide. Glucose is used by the plant as its own
generated food source. Glucose can also remain in the plant and may serve as an energy source for a
consumer. Oxygen gas is A by-product of the photosynthesis reaction, and is released from the plant
through the stomata.
Distribute the Products of Photosynthesis page.
1. Place your Products of Photosynthesis page directly to the right of the Energy Transformation
through Photosynthesis page.
2. Obtain a paper model of glucose from your teacher.
3. Count the number of carbon atoms in the paper model of glucose. Take that number of carbon
atoms from the pile of atoms on the energy transformation arrow and set them aside in a stack.
4. Count the number of hydrogen atoms in the paper model of glucose. Take that number of
hydrogen atoms from the pile of atoms on the energy transformation arrow and add them to
the stack of carbon atoms.
5. Count the number of oxygen atoms in the paper model of glucose. Take that number of oxygen
atoms from the pile of atoms on the energy transformation arrow and add them to the stack of
carbon and hydrogen atoms.
6. Set your stack of carbon, hydrogen and oxygen atoms on the Products of Photosynthesis page in
the space labeled: glucose.
7. Take the remaining atoms from the pile of atoms on the energy transformation arrow and
distribute them equally on the spaces provided on the Products of Photosynthesis page.
Monitor to see that student distribute the remaining 12 plastic chips equally on the remaining spaces so
that each space has two chips labeled “O.” Students will discover that after forming the glucose
molecule, they will have 12 oxygen atoms remaining. This, of course, is the oxygen that plants release
back to the atmosphere and that animals breathe in during respiration. Students will already be familiar
with the element oxygen, however, this is a good opportunity to introduce them to the fact that oxygen
is diatomic. This means that it naturally is found in pairs. Ask students to identify how energy is
interacting with matter at this stage of the model. Students should mention that at this stage of the
process of photosynthesis, the radiant energy has been transformed into chemical energy and is stored
in the form of glucose (sugar) and in the oxygen gas that form as the products of the chemical reaction.
8. Answer the questions for Part III in the Explore Student Journal.
9. Wrap up by completing the Reflection and Conclusions questions in the Explore Student Journal.
Student Journal
1. How many hydrogen atoms in total appear as any part of the products?
12
Were any hydrogen atoms gained or lost as a result of photosynthesis?
No
2. How many carbon atoms in total appear as any part of the reactants?
6
Were any carbon atoms gained or lost as a result of photosynthesis?
No
3. How many oxygen atoms in total appear as any part of the reactants?
18
Were any oxygen atoms gained or lost as a result of photosynthesis?
No
4. Are all of the atoms used to create the glucose?
No
5. Why does it make sense to call oxygen a by-product of photosynthesis?
Only oxygen atoms were left after getting the atoms needed to create glucose.
6. Explain how the model shows storage of chemical energy.
The chemical energy is stored within the newly created products; the model shows energy storage
within the stack of chips.
7. Add arrows and additional labels to the picture below to demonstrate the information you
learned in this activity about photosynthesis including the energy involved in the process.
Photosynthesis Diagram
Students should draw arrows from CO2, H2O, and the Sun to the leaf. They should draw and label an
arrow to show O2 moving from the leaf to the atmosphere. They should label the radiant energy from
the Sun and indicate the transformation to chemical energy.
Reflections and Conclusions
1. What role does the Sun’s energy play in the process of photosynthesis?
Radiant energy from the Sun is required for photosynthesis to occur; it is transformed to chemical
energy as a result of the process.
2. Is matter created or destroyed during the photosynthesis process? Explain your answer.
No, we started and ended with the same number of atoms.
3. How do humans benefit from plants going through photosynthesis?
We cannot consume radiant energy. We rely on the process of photosynthesis to change radiant energy,
water, and carbon dioxide into a substance containing chemical energy that our bodies can use for fuel.
4. Do you think the process of photosynthesis only occurs one time in a plant leaf?
Student answers will vary. This question provides the teacher with an opportunity to extend instruction
about the process of photosynthesis. Example answer: No. Just as we need to eat multiple times during
each day, a plant needs to constantly receive more energy, therefore, it will have to undergo
photosynthesis again and again to make the needed food for the plant.
5. Use your understanding of photosynthesis to follow and describe how carbon ends up in the
stomach of a rabbit. Include where carbon enters the process and what form it is in as well as
the steps of what happens to the carbon throughout the process.
Carbon begins in the atmosphere as carbon dioxide. The carbon dioxide enters the leaf through the
stomata and becomes a reactant in the process of photosynthesis. The carbon is included in the
product: glucose. The rabbit eats the plant and the stored carbon in the glucose ends up in the stomach
of the rabbit.
6. Plants are frequently classified as Producers because of the process of photosynthesis. Explain
why this is an appropriate title.
During the process of photosynthesis, the glucose is produced from carbon dioxide and water. The plant
is able to produce or make its own food with the process.
7. Predict what would happen on Earth if an explosive action, for example, an asteroid crash forced
material into the atmosphere such that the amount of radiant energy was significantly reduced
for many years.
Student answers will vary. Look for understanding that photosynthesis requires radiant energy from the
Sun, and a reduction would reduce the amount of chemical energy stored as glucose that is available for
plant use and for consumers.
8. Review the model you created with the plastic chips. Count the number of carbon dioxide stacks
that were reactants. Count the number of water stacks that were reactants. Count the number
of oxygen stacks that resulted as products. Record below:
6 water H2O
6 carbon dioxide CO2
6 oxygen O2
1 glucose C6H12O6
Use the numbers above the fill in the symbolic photosynthesis reaction below:
6 H2O + 6 CO2 → 6 O2 + C6 H12O6
The symbolic representation of the photosynthesis reaction is not part of the standard, however, some
teachers like to introduce the concept at this time.