Title: Photosynthesis Phun
Author: Jean Marie Buschur
Overview: An activity using Skittles to show how the photosynthesis reaction balances.
Suggested grade level(s):
7-10
Concepts covered: Photosynthesis, Cellular Respiration, Balanced Equations,
Conservation of Mass, Chemical Formulas and Names
Standards: Based on South Carolina 7th grade standards.
III.
Earth Science
Unit of Study: Ecology — The Abiotic Environment
A. Structure of the Earth System
6.
For ecosystems, the major source of energy is sunlight. Energy entering
ecosystems as sunlight is transferred by producers into chemical energy
through photosynthesis. That energy then passes from organism to
organism in food webs.
a. Describe how sunlight, through photosynthesis, is transferred by
producers into chemical energy.
Length of lesson: 90 minutes (7th grade)
Materials required: Student worksheet
Student cut-out sheet
Papertowels
Skittles separated by color and numbered (36)
Dixie cups for the skittles
Scissors
Lesson Format
Phase I.
Engage
Is what goes in really what goes out? When cells take in materials to make food, do they
loss anything in the process?
Write the equation for photosynthesis using the students input. Explain how the
stoichiometry works if not covered before.
Phase II.
Explore
Using the student activity sheet on page 2 follow through the steps to build the
photosynthesis equation.
Page 1 of 7
This lesson plan is part of the 2006 GK-12 Institute
A key follows the student sheet.
Page 2 of 7
This lesson plan is part of the 2006 GK-12 Institute
Photosynthesis Phun
Name:
Date:
Bell:
Photosynthesis is the chemical reaction in which plants and other organisms make
food for their cells. The food is made in the form of glucose (C6H12O6) which is a type of
sugar. This reaction occurs in small compartments of each cell called the chloroplasts.
1. Write the equation for photosynthesis here:
2. For the reactant side of the equation write each chemical formula, the name of the
molecule it stands for and the number of each molecule:
Name
Number
Formula
_________________ = ________________________
______
_________________ = ________________________
______
3. What is the source of energy for this equation to take place? ___________
4. For the product side of the equation write each chemical formula, the name of the
molecule it stands for and the number of each molecule:
Formula
Name
Number
_________________ = ________________________
______
_________________ = ________________________
______
5. Write the names and symbols of the three elements used in this equation and color you
will make this element (red, orange, purple, green, or yellow).
Name
Color
Symbol
___________ = _____________________ = ____________
___________ = _____________________ = ____________
___________ = _____________________ = ____________
We are now going to build this equation. Each piece will represent one element. First,
cut out and arrange the pieces of the equation on your table. Under each piece lay a piece
of paper towel.
Next, arrange your skittles to form the molecules in each step of the reaction.
Once you have your pieces laid out ask a teacher to check your work.
Page 3 of 7
This lesson plan is part of the 2006 GK-12 Institute
6. Fill in the following chart with the numbers of each element based on your model in
front of you.
Reactants
Products
Number of Carbons
Number of Hydrogens
Number of Oxygens
Total numbers (add up
first 3 columns)
Check with the teacher to make sure you have this filled in correctly.
7. The number of elements on the side of the reactants is _______________.
The number of elements on the side of the products is _________________.
What conclusion can you draw from this? ____________________________
________________________________________________________________________
________________________________________________________________________
______________________________________.
When the numbers on an equation on both sides are equal this is called the Law of
Conservation of Matter.
8. Why do cells do photosynthesis? _________________________________
_____________________________________________________________.
9. What molecule represents food that is made in photosynthesis?
_____________________________________________________________.
10. List the reactants. ___________________________________________
_____________________________________________________________
11. List the products. ___________________________________________
_____________________________________________________________
Page 4 of 7
This lesson plan is part of the 2006 GK-12 Institute
Photosynthesis Phun Key
Name: Key
Date:
Bell:
Photosynthesis is the chemical reaction in which plants and other organisms make
food for their cells. The food is made in the form of glucose (C6H12O6) which is a type of
sugar. This reaction occurs in small compartments of each cell called the chloroplasts.
1. Write the equation for photosynthesis here:
6H2O + 6CO2 + light energy Æ C6H12O6 + 6O2
* The students should be able to do #’s 2-4 on their own.
2. For the reactant side of the equation write each chemical formula, the name of the
molecule it stands for and the number of each molecule:
Name
Number
Formula
__H2O ___________ = ___Water________________
___6___
__ CO2___________ = ___Carbon Dioxide________
___6___
3. What is the source of energy for this equation to take place? __sunlight_________
4. For the product side of the equation write each chemical formula, the name of the
molecule it stands for and the number of each molecule:
Name
Number
Formula
___ C6H12O6_______ = ____Glucose_____________
__1____
____ O2___________ = _____Oxygen____________
__6____
* The students will get three colors of Skittles, they get to chose what to make each color.
5. Write the names and symbols of the three elements used in this equation and color you
will make this element (red, orange, purple, green, or yellow).
Name
Color
Symbol
___C________ = ____Carbon___________ = ____________
___H________ = ____Hydrogen_________ = ____________
___O________ = ____Oxygen___________ = ____________
We are now going to build this equation. Each piece will represent one element. First,
cut out and arrange the pieces of the equation on your table. Under each piece lay a piece
of paper towel.
Page 5 of 7
This lesson plan is part of the 2006 GK-12 Institute
* Their set-up should have the symbols above the papertowels laid out in the correct
order.
Next, arrange your skittles to form the molecules in each step of the reaction.
Once you have your pieces laid out ask a teacher to check your work.
* It is easiest to spot check the Skittles laid out as you walk past. They should have used
all of one color (the oxygens) but the rest of the colors should not be used up. I kept
these extras and used them in another class.
6. Fill in the following chart with the numbers of each element based on your model in
front of you.
Reactants
Number of Carbons
Number of Hydrogens
Number of Oxygens
Total numbers (add up
first 3 columns)
6
12
18
36
Products
6
12
18
36
Check with the teacher to make sure you have this filled in correctly.
7. The number of elements on the side of the reactants is _36______________.
The number of elements on the side of the products is ___36______________.
What conclusion can you draw from this? __Equal on both sides, what went in came out,
etc.____________________________________________________________________.
When the numbers on an equation on both sides are equal this is called the Law of
Conservation of Matter.
8. Why do cells do photosynthesis? _to make food______________________________.
9. What molecule represents food that is made in photosynthesis?
__glucose C6H12O6_______________________________________________________.
10. List the reactants. _water H2O, carbon dioxide CO2 __________________________
11. List the products. __glucose C6H12O6, oxygen 6O2_________________________
_____________________________________________________________
Page 6 of 7
This lesson plan is part of the 2006 GK-12 Institute
Phase III.
Explain
As the students finish the questions and had their set-up checked, I allowed them to eat
the Skittles.
Once they had finished the questions I went over them and explained why the reaction
balanced.
.
Phase IV.
Elaborate
Ask the students how the photosynthesis reaction relates to cellular respiration. Have the
students talk through how cellular respiration is the reverse of photosynthesis. If needed
they can move around the pieces on their table and see how cellular respiration is the
exact opposite of photosynthesis.
Phase V.
Evaluate
A sample rubric.
CATEGORY
4
3
2
1
All variables are
clearly described
with all relevant
details.
All variables are
clearly described
with most
relevant details.
Most variables
are clearly
described with
most relevant
details.
Variables are not
described OR the
majority lack
sufficient detail.
Professional
looking and
accurate
representation of
the data in tables.
Tables and are
labeled and titled.
Accurate
representation of
the data in tables.
tables are labeled
and titled.
Activity
Professional
looking and
accurate
representation of
the equation.
Accurate
representation of
the equation.
The model was
not an accurate
representation of
the equation.
No model are
presented.
Participation
Played an active
role in the class
discussion of the
activity.
Participated in or
actively listened
to the class
discussion.
Listened
somewhat to the
discussion.
No attention or
participation in
the discussion.
Worksheet
Page 7 of 7
This lesson plan is part of the 2006 GK-12 Institute
Tables are not
accurate
representation of
the data.
No tables are
presented.