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Plants: Photosynthesis Grade 3-5

BACKGROUND Photosynthesis is the big name for the process by which convert from into energy for food. Photosynthesis, derived from the Greek words photo, meaning "," and synthesis "putting together."

This process also requires and dioxide. Plants are able to absorb rain water through their and receive from the air through their . The carbon dioxide is in the air as a result of the air that , including , breathe out. Plants are able to store these chemicals in their leaves.

6CO2 + 6H20 + (energy) → C6H12O6 + 6O2 Carbon dioxide + water + energy from light produces and .

Glucose is often referred to as .

Plant cells are unique in that they also contain special components called . Chloroplasts are filled with a substance called . It is this substance which gives 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.

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 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 .

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 . This is the excess water not used in photosynthesis.

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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 of living things, the process and diversity of , 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 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 Mastery Questions  Photosynthesis  See Lesson  Transpiration  Chlorophyll  Chloroplasts  Carbon dioxide  Oxygen  Water  Sugar – glucose  Roots  Leaves  Water vapor  Respiration 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 , 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 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 to grow. (A water student for each plant comes from the floor to his/her plant student.) Plants absorb carbon dioxide from the . (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 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

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How Does Photosynthesis Work? Comparison of Photosynthesis and 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. - 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 From the Kit Provided by Teacher Have students identify safety procedures or  hand lens  Small potted plants – enough equipment to be used when handling plants. (Wash for groups to share. hands, keep hands away from mouth, and identify  masking tape or aluminum allergies.) foil  petroleum jelly  re-sealable plastic bags  disposable gloves  safety goggles  science learning logs

Key Vocabulary Mastery Questions  Photosynthesis  See Lesson  Transpiration  Carbon dioxide  Oxygen  Water  Sugar – glucose  Water Vapor  Stomata 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, , 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 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 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, ). 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 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 . 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

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