Download Photosynthesis Grade 3-5 BACKGROUND

Plants: Photosynthesis
Grade 3-5
BACKGROUND
Photosynthesis is the big name for the process by which plants convert energy from sunlight into energy for food.
Photosynthesis, derived from the Greek words photo, meaning "light," and synthesis "putting together."
This process also requires water and carbon dioxide. Plants are able to absorb rain water through their roots and receive
carbon dioxide from the air through their leaves. The carbon dioxide is in the air as a result of the air that animals,
including humans, breathe out. Plants are able to store these chemicals in their leaves.
6CO2 + 6H20 + (energy) → C6H12O6 + 6O2
Carbon dioxide + water + energy from light produces glucose and oxygen.
Glucose is often referred to as sugar.
Plant leaf cells are unique in that they also contain special components called chloroplasts. Chloroplasts are filled with a
green substance called chlorophyll. It is this substance which gives plant leaves their green appearance and enables
them to absorb sunlight. When plant cells have water, carbon dioxide and sunlight the chemical process of
photosynthesis occurs. When this happens the water, carbon dioxide and sunlight join together to form a sugar called
glucose, plus water, and oxygen. In this form the plants can use the glucose, and water for food and release the oxygen
back into the air for consumption by animals, including humans.
www.eschooltoday.com

Why Photosynthesis Matters?
Photosynthesis lesson plans would not be complete without an emphasis on the significance of photosynthesis for the
entire population of the world's plants and animals. Without photosynthesis plants would not produce oxygen. Without
oxygen to breathe animals could not live. Without animals plants would not receive carbon dioxide. Likewise neither
could exist without sunlight and water. Students should learn from this lesson that photosynthesis is the backbone of
the most basic and necessary relationship on earth.
Transpiration is the process of water movement through a plant and its evaporation from aerial parts, such as from
leaves but also from stems and flowers. This is the excess water not used in photosynthesis.
cikgurozaini.blogspot.com
BASIC LESSON
Objective(s)
Students will be able to…
 Understand and explain the process of photosynthesis.
State Science Content Standard(s)
Standard 3: Students, through inquiry process, demonstrate knowledge of characteristics, structures and function of
living things, the process and diversity of life, and how lining organisms interact with each other and their
environments.
2. Explain how organisms and systems of organisms obtain and use energy resources to maintain stable conditions.
a. Identify plant structures involved in photosynthesis and transpiration
b. Identify compounds involved in photosynthesis and transpiration.
c. Explain the process of photosynthesis and transpiration in terms of key structures and compounds that are
utilized,
d. Explain the relationship between photosynthesis and transpiration.
Materials
Safety
From the Kit
Provided by Teacher
 None
 Photosynthesis
 Computer/projector for
Activity Cards
PowerPoint
Key Vocabulary












Photosynthesis
Transpiration
Chlorophyll
Chloroplasts
Carbon dioxide
Oxygen
Water
Sugar – glucose
Roots
Leaves
Water vapor
Respiration
Mastery Questions

See Lesson
Detailed Plan
Photosynthesis
Engage
Ask the students what a plant needs in order to grow. Write down their responses on the board or chart paper to refer
to later. Share that many of the items they brainstorm are involved in a process called photosynthesis and they are
interconnected with each other.
Explanation
Found on the website is a PowerPoint which illustrates and explains photosynthesis and transpiration. Change by adding
or subtracting information to fit your classroom needs.
Exploration
To help illustrate the process of photosynthesis and transpiration, the students will role play the different parts of the
process. Each student assumes a role in the process of photosynthesis. The roles are: the sun, the plant, water, carbon
dioxide, energy, sugar and a narrator. The sun shines in the center of the room. Plants are surrounded by energy, water
and carbon dioxide which walk around them and then sit down. Sugar and oxygen then take a turn to walk around the
plants. The narrator describes the process as it happens. Animals (people) can also be included giving off carbon dioxide
and receiving oxygen. The students might wish to repeat the process over and over to show how the relationship
continues. Use the diagram found in the background information to help orchestrate the role play. Also posting the
chemical reaction will help clarify the process. A large open area should be used.
Script – feel free to improvise – this is just a guide.
(To start, have the Sun student stand in the middle of the room and have 3 plant students standing about 4 feet away.
Plant students will not move)
The sun provides the energy for photosynthesis to occur. Plants need the energy to produce food and grow. (An energy
student for each plant leaves the sun and go to his/her plant student.) Plants also need water from the soil to grow. (A
water student for each plant comes from the floor to his/her plant student.) Plants absorb carbon dioxide from the
atmosphere. (A carbon dioxide student for each plant goes to a plant student.) Carbon dioxide, water, and energy react
together to make glucose (sugar) and oxygen. (The carbon dioxide, water, and energy student come together and from
them a sugar and oxygen student will leave.) Animals or people breathe oxygen and give off carbon dioxide. This is
called respiration. (Ask the students how they would show how the animals and plants together would work –
respiration and photosynthesis.)
Ask the students how they would show transpiration using the role play model. (Water student would leave the plant as
water vapor.)
Assessment
Students can draw the process of photosynthesis taking effort to include every element of the process. Give them the
terms and objects you would like to see in the drawing to assess their understanding of photosynthesis and
transpiration.
See resources below for the Plant Nutrition interactive lesson which could be used for assessment or closure.
Resources
Adapted from a lesson written by: Lynn-nore Chittom and edited by: Trent Lorcher • updated: 2/8/2012
Also Recommend...
How Does Photosynthesis Work?
Comparison of Photosynthesis and Cellular Respiration
The Compound Sugar: Explanation and Molecular Breakdown
Comparison of Cellular Respiration and Photosynthesis
Creating a Photosynthesis Activity in the Classroom
This is a great interactive lesson students can do individually in a computer lab or as the entire class.
Plant Nutrition - Interactive Lesson
ADVANCED LESSON
Objective(s)
Students will be able to…
 Observe and explain photosynthesis and transpiration using a plant as an example.
State Science Content Standard(s)
Standard 3: Students, through inquiry process, demonstrate knowledge of characteristics, structures and function of
living things, the process and diversity of life, and how lining organisms interact with each other and their
environments.
2. Explain how organisms and systems of organisms obtain and use energy resources to maintain stable conditions.
a. Identify plant structures involved in photosynthesis and transpiration
b. Identify compounds involved in photosynthesis and transpiration.
c. Explain the process of photosynthesis and transpiration in terms of key structures and compounds that are
utilized,
d. Explain the relationship between photosynthesis and transpiration.
Materials
Safety
Provided by Teacher
Have students identify safety procedures or
From the Kit
equipment to be used when handling plants. (Wash
 hand lens
 Small potted plants – enough
hands, keep hands away from mouth, and identify
for groups to share.
allergies.)
 masking tape or aluminum
foil
 petroleum jelly
 re-sealable plastic bags
 disposable gloves
 safety goggles
 science learning logs
Key Vocabulary








Photosynthesis
Transpiration
Carbon dioxide
Oxygen
Water
Sugar – glucose
Water Vapor
Stomata
Mastery Questions

See Lesson
Detailed Plan
Observing Photosynthesis
Engage
Begin the activity by having students brainstorm a list of things they need to survive. Students should share their list and
through discussion of what we cannot live without, narrow the list down to air, water, food, and shelter. Have students
brainstorm a list of things plants need to survive. Have students share their list and discuss the basic needs of
plants. Help students remember the needs of plants with this acronym (LAWNS – Light, Air, Water, Nutrients, and
Space). Students should compare and contrast the needs of plants and animals through class discussion.
Ask students where their food comes from (grocery store, etc.). Tell students that plants are special because they can
make their own food through a process called photosynthesis. Explain that photosynthesis is a process where plants
combine carbon dioxide and water and in the presence of sunlight, they are able to produce water, oxygen, and
sugar. Using these terms, write the photosynthesis word formula on the board (See Background). Explain that
photosynthesis takes place primarily in the leaves of the plant and that the green pigment chlorophyll helps
photosynthesis to take place.
To demonstrate that photosynthesis occurs in the leaves, have students complete the following activity. (Note: if
supplies are limited, this may be done as a teacher demonstration.)
Exploration
Place students in groups and give each group a plant with soft leaves, such as a geranium, to observe. Students should
record all observations in their science learning logs or journals. Direct students to place a piece of masking tape or
aluminum foil over a small section of one leaf and place the plant in a sunny area of the classroom or under artificial
light. In three days, students should remove the masking tape and record their observations. Discuss any changes that
occurred in the leaf. (The color should have faded or turned yellow under the tape.) Hold a class discussion to
determine why the leaf changed colors and relate the changing of the colors to the plant’s need for sunlight during
photosynthesis.
Observing Transpiration
Engage
Begin a discussion about ways to show that a plant is conducting photosynthesis and transpiration. Review what
transpiration is. (See background) Prompt the students by having them think of what they would expect to see if a
person said that he had cooked a meal (Pots on the stove, someone stirring, food served on plates). Next, ask students
to consider what they would expect to find produced if a plant was conducting photosynthesis (Water absorbed into the
plant, oxygen, sugar, starch). Ask them what they would see if a plant is conducting transpiration. (Evaporated water.)
Ask students to recall the times that they were under a tree and felt drops of water fall on them, but it wasn’t raining.
Explain that this water came from the tree as a by-product of photosynthesis which is occurring inside the leaf. Ask
students to think of questions regarding the water falling off the tree and what is happening inside of the leaf. (Students
may wonder how the water got on the outside of the leaf when it is being created inside the leaf.)
Exploration
Ask the class, “How can we prove that water is released from the plant’s leaves during photosynthesis?” One possible
experiment is to have student groups place 3 plant leaves in a plastic re-sealable bag and place in a sunny window or
under artificial light. As a control, place an empty re-sealable bag in the window. Ask students why this was done. The
next day, have the students make observations of the bags. Students should see condensation (water) on the bags with
leaves. Ask the students where the condensation came from (the leaves)
Allow students to hypothesize how the leaf sets the water free. (They may think that there must be an opening in the
leaf.) Explain that if there are holes in the leaf allowing the water to escape, they may be able to plug them up to stop
the water from escaping. To determine whether or not there are openings in the leaf, have students smear both sides of
a leaf on a potted plant with petroleum jelly and place a clear plastic bag around the leaf, sealing it at the petiole.
Explain to students that the petiole is the stalk of the leaf that attaches the blade to the stem of the plant. Discuss the
role of the petroleum jelly (to plug the holes). Guide students to establish a control (a plant that has uncoated leaves
sealed in a plastic bag). Again, allow the bags to sit overnight and have the students make observations of the bags the
next day. The students will observe a collection of water in the bag of the uncoated leaves. Relate the formation of the
water on the inside of the bags to the release of water (transpiration) from the leaves during photosynthesis.
Explanation
Introduce the term stomata as the opening in the leaves that allows the water to escape. Later students may wish to
alternate the side of the leaf that is smeared with the petroleum jelly to explore further which side has the stomata.
Allow students to observe the stomata of leaves using a hand lens or microscope, if available. Students should infer that
the excess water created as a by-product of photosynthesis could escape from the plant through the stomata. Note:
Aquatic plants have stomata on the top of the leaves, while most land plants have stomata on the bottom of the leaf.
Refer the students to the photosynthetic word formula and ask them to consider that if the stomata open to allow extra
water out of the plant, what else could be escaping from the plant through the stomata (Oxygen)? Could the stomata
open to let something else pass into the plant? Looking back at the photosynthetic word formula, the student will search
for the matter for which they have not accounted (Carbon dioxide). The students should infer that carbon dioxide could
enter the plant through the stomata. This provides a junction for a discussion about the interdependence of plants and
animals for gas exchanges.
Assessment
Students write an explanation in their journals of what happened to the plants in each step of the photosynthesis
activity and transpiration activity. Have them explain how photosynthesis and transpiration are related. Have them
explain how they are different.
Resources
Lesson Plans/Resources:





Photosynthesis
Photosynthesis Pete's PPTs
Kids Konnect Photosynthesis
Photosynthesis - How much do you know
Plants - A life form we can not live without
Interactive Activities:

Illuminating Photosynthesis
EXPLORE MORE