Rotation 2
Fall #2 PART 2: Leaves: Photosynthesis
Objectives
Students will be able to:
• identify what plants need
for photosynthesis to
occur;
• demonstrate
understanding of
photosynthesis concepts
through play a game
Oregon Content
Standards:
1.1L.1- Compare and
contrast characteristics
among individuals within
one plant or animal group.
2.3S.1- Observe, measure,
and record properties of
objects and substances
using simple tools to
gather data and extend the
senses.
2.3S.2- Make predictions
about living and non-living
things and events in the
environment based on
observed patterns.
2.3S.3- Make, describe,
and compare observations,
and organize recorded
data.
4.2L.1- Describe the
interactions of organisms
and the environment
where they live.
5.1L.1- Explain that
organisms are composed
of parts that function
together to form a living
system.
Lesson Length
20-25 minutes
Materials
• white board and marker
• yellow object for the sun
• colored head/armbands
• leaf part cards
Background
Photosynthesis is the process of converting light energy into
chemical energy that can be used by biological systems
(specifically plants but also algae and bacteria).
Light rays from the sun strike the leaf (in specific, chlorophyll.
Chlorophyll cannot absorb green light so is reflected
back—this is why we see green) which traps the light energy.
Water molecules, which have been absorbed by the roots and
transported to the leaves, are split into hydrogen and oxygen,
as a result of the light energy. Carbon dioxide is taken in from
the air through openings in the leaf called the stomata—tiny
pores.
The hydrogen combines with the carbon dioxide to form
glucose (sugar for the plant). The oxygen left over from the
water molecules is released into the atmosphere through the
stomata (which we use to breathe!). As the stomata releases
oxygen, it allows more carbon dioxide in—which allows
photosynthesis to continue.
How do plants use food?
Light energy!chemical energy!glucose (sugar)
The energy is stored as glucose (sugar) and must be broken
down into a form that the plant can use. Plants cells can
release the stored energy from glucose through respiration.
Plant leaves absorb oxygen from the air and combine it with
glucose. Carbon dioxide and water are given off through the
leaves and the plant uses the energy released from the
glucose.
Plants are called producers: They can make their own
food—through photosynthesis.
Humans and Animals are called consumers: They cannot
make their own food. They rely on eating other plants or
animals that eat plants.
Preparation
Prepare a playing field.
Review background info.
Vocabulary
photosynthesis, water,
carbon dioxide, leaf,
chlorophyll, glucose,
respiration, producer,
consumer
Garden Tasks
o Foliar feeding with a
dissolvable organic
fertilizer, sprayed directly
on leaves.
o Weed and put weeds
into groups with similar
leaf shapes.
o Mulch with leaves or
collect them to mulch
with later
o Removing dead, excess
leaves from base of
plants
o Harvesting a leafy meal
Photosynthesis
http://7x9.verale.uni.me/P6P
Introduction
Procedure
Introduction
Bring the entire class to the gathering place. Ask students
how plants eat and drink. Define photosynthesis. Tell
students they will be learning about photosynthesis through a
game.
Activities
Game #1: Race to the Sun
One person is the sun (holds something yellow),
photosynthesis can occur only when the sun is up. Have
“sun” practice making the sun go up and down. The sun will
stand at the end of the playing field.
Pick two volunteers to be plants. They will be rooted in place
on the other side of the playing field from the sun.
Two more volunteers will be leaves. Each plant gets a “leaf”.
The “leaf” starts out standing by their plant.
Everyone else is split in half. They make two single file lines
behind the sun. One line is water. The other is carbon
dioxide.
When the game starts (the sun is held up) the leaves will run
to the CO2 or H2O lines and take the first person from the
line back to their plant. That “molecule” links arms with the
plant while the leaf runs to get another “molecule”. This
allows the plant to “grow” as the chain of students gets
longer. The leaves have to alternately collect CO2 and H2O
“molecules” so that the line they create coming off of their
plant is alternating CO2, H2O, CO2, H2O. The first plant line
that can touch the sun wins. So the line of students will want
to be growing toward the sun. If the leaf is still moving when
the sun goes down, their plant looses the last two people in
its chain who have to go back to their original molecule line.
You can add predators to the mix (consumers) who will come
and cut off part of the plant. You can also have the days get
shorter and longer for winter and summer.
Game #2: Photosynthesis Tag
This game is similar to blob tag, in which tagged players join an increasingly
unwieldy chain that tries to run and tag more players. In blob tag, if a chain
breaks, smaller groups can continue playing. With photosynthesis tag, each
set of players must form a representation of the photosynthetic process.
Divide students into these roles:
o
o
o
o
o
o
Chlorophyll (green headband)
Sunlight (yellow headband)
Hydrogen (dark blue headband)
Oxygen (light blue headband)
Carbon Dioxide (black headband)
Sugar (brown headband)
The game simplifies the complex process of photosynthesis. The game ends
when carbohydrates have been produced by carbon dioxide, water, sunlight,
and chlorophyll. The number of photosynthetic processes occurring in the
game will depend on the number of students in your class. You need a
minimum of twelve students, which would end the game with two completed
processes. More students will result in more photosynthesis occurring.
The area of play will depend on the number of students in the game and their
energy level. You will need an open space, the gymnasium or an outdoor
field. If no one is tagged in the first 30 seconds, reduce the space (the
students can remain playing). Place clear boundary markers so the students
remain in the area.
o
o
o
o
o
o
o
o
o
All students start the game by milling about the playing area. Hydrogen and
oxygen molecules should hold hands so to represent water (to keep things
simple, there is only one player representing the hydrogen molecules).
When you call, “photosynthesize,” the chlorophyll students start chasing the
students wearing the yellow sun headbands.
When the chlorophyll absorbs the sunlight (represented by taking that
player’s hand), together they chase the water molecule.
The sun student must grab the hand of the hydrogen molecule, releasing the
oxygen molecule into the atmosphere. The oxygen player can continue to
walk or run about the playing field, but they will not be added to a chain.
The chain of students now chases a carbon dioxide molecule. The hydrogen
must grab the hand of, the carbon dioxide molecule.
Finally, the group is able to make sugar. The carbon dioxide molecule tags a
sugar molecule, representing that the process is complete.
When a group collects sugar, they should go over to the teacher to confirm
they are in the proper order – chlorophyll, sunlight, hydrogen, carbon dioxide,
and sugar.
If at any point in the game, any student holding hands breaks the link then all
the joined players must disperse. The hydrogen molecule joins with an
oxygen molecule. Those students must again try to connect.
The game ends when only oxygen and extra sunlight players are roaming the
playing field.
-Susan Caplan from suite101.com
Note: Students may begin to catch on that this is really the opposite of
tag—i.e. you want to get tagged to win.
Wrap-up
After the group has played one of the games, gather in a circle to debrief the
game. Ask the group: How was that game like real life, how was it different?
Ask them what the game taught them about photosynthesis.
Adaptations
To add complexity
1) Introduce Photosynthesis by writing the word on the board. Ask students to
break the words into two parts. Most will come up with ‘Photo’ and
‘Synthesis’. Give the definition for each- ‘photo’ meaning light and ‘synthesis’
work together. Ask the students to hypothesize in small groups what
photosynthesis means, based on what they already knew and what they’ve
just learned. Then compare their ideas to the actual definition. Draw a
diagram of photosynthesis on the board as you explain. Then tell the group
they will be playing a game to help them better understand the process.
2) End with a leaf taste test. Have volunteers collect leaves for this ahead of
time. After finishing the game split the students back into their groups. Have
them close their eyes and give each a bit of a leaf to taste. They will try to
guess which leaf they tasted.
3) Add on Part 1 of the Leaf Parts lesson for a longer lesson.
Rainy Day: Look at Part 1