Photosynthesis: Capturing Sunlight

Active learning works for photosynthesis because students often hold misconceptions about where plants get their food and how energy moves through ecosystems. By engaging in hands-on investigations and collaborative discussions, students directly observe the processes and correct their understanding through evidence.

• 6th Grade
• Science
• 3 activities
• 15 min–50 min

Learning Objectives

1. Explain the chemical equation for photosynthesis, identifying reactants and products.
2. Analyze the role of chlorophyll in absorbing light energy for photosynthesis.
3. Construct a diagram illustrating the inputs (sunlight, water, carbon dioxide) and outputs (glucose, oxygen) of photosynthesis.
4. Compare the energy conversion in photosynthesis to the energy release in cellular respiration.

Peer Teaching

⏱ 45 min·Pairs

Peer Teaching: The Carbon Cycle Comic

Students create a comic strip where a carbon atom is the main character. They must show the atom moving from the air into a plant (photosynthesis) and then into an animal (respiration), explaining the change at each step.

Prepare & details

Explain how plants turn sunlight and air into solid wood and leaves.

Facilitation Tip: During The Carbon Cycle Comic, have students sketch and label the movement of carbon atoms through the cycle, ensuring they trace them from CO2 to glucose and back to CO2.

Setup: Presentation area at front, or multiple teaching stations

Materials: Topic assignment cards, Lesson planning template, Peer feedback form, Visual aid supplies

• Understand
• Apply
• Analyze
• Create
• Self-Management
• Relationship Skills

Inquiry Circle

⏱ 50 min·Small Groups

Inquiry Circle: Elodea Bubbles

Groups place aquatic plants (Elodea) in water under different light conditions. They count the oxygen bubbles produced to see how light intensity affects the rate of photosynthesis, then share their data to find patterns.

Prepare & details

Analyze the role of chlorophyll in the process of photosynthesis.

Facilitation Tip: During Elodea Bubbles, remind students to keep the plant underwater to trap oxygen bubbles and to gently tap the stem to dislodge any air pockets that might block light absorption.

Setup: Groups at tables with access to source materials

Materials: Source material collection, Inquiry cycle worksheet, Question generation protocol, Findings presentation template

• Analyze
• Evaluate
• Create
• Self-Management
• Self-Awareness

Think-Pair-Share

⏱ 15 min·Pairs

Think-Pair-Share: The Oxygen Mystery

Students discuss with a partner: 'If plants make oxygen, why do they also need to perform cellular respiration?' They then share their conclusions about how plants use the food they make to stay alive.

Prepare & details

Construct a diagram illustrating the inputs and outputs of photosynthesis.

Facilitation Tip: During The Oxygen Mystery, ask students to propose a hypothesis before sharing their reasoning, then compare their initial thoughts with their partner’s to refine their explanations.

Setup: Standard classroom seating; students turn to a neighbor

Materials: Discussion prompt (projected or printed), Optional: recording sheet for pairs

• Understand
• Apply
• Analyze
• Self-Awareness
• Relationship Skills

Teaching This Topic

Teach this topic by starting with a familiar phenomenon, like a tree growing taller without soil adding to its weight, to confront the misconception that plants eat soil. Use analogies like a solar panel converting sunlight to energy to help students visualize photosynthesis. Avoid overemphasizing the chemical equation too early; focus on the process and energy flow first, then introduce the formula as a summary.

What to Expect

Successful learning looks like students accurately explaining the inputs and outputs of photosynthesis, connecting it to cellular respiration, and identifying how energy flows between plants and animals. They should also be able to address common misconceptions using evidence from their activities.

Watch Out for These Misconceptions

Common Misconception

During The Carbon Cycle Comic, watch for students who trace carbon only as a gas or only in plants, missing its movement through soil, animals, and the atmosphere.

What to Teach Instead

During The Carbon Cycle Comic, ask students to include at least three stops in the cycle (e.g., plant, animal, decomposer) and label the form of carbon at each stop to ensure they see the full cycle.

Common Misconception

During The Oxygen Mystery, watch for students who assume plants release oxygen only during the day and forget that respiration happens continuously.

What to Teach Instead

During The Oxygen Mystery, have students discuss how a seed grows underground at night and connect that to the need for stored energy and constant respiration, even without light.

Assessment Ideas

Quick Check

After The Carbon Cycle Comic, present students with a partially completed photosynthesis diagram showing only sunlight and water as inputs. Ask them to identify the missing reactant (CO2) and label the two products (glucose and oxygen) on their comics.

Discussion Prompt

During Elodea Bubbles, pose the question: 'Why do you think bubbles form on the Elodea leaves?' Listen for students to connect bubble formation to oxygen release from photosynthesis.

Exit Ticket

After The Oxygen Mystery, on an index card, have students write the chemical formula for glucose (C6H12O6) and explain in one sentence how plants obtain the energy to create it. They should also list one gas that enters the plant (CO2) and one gas that leaves (O2) during this process.

Extensions & Scaffolding

• Challenge students to design an experiment testing how different colors of light affect photosynthesis rates in Elodea.
• For students who struggle, provide a partially completed diagram of the carbon cycle to label before creating their own comic.
• Deeper exploration: Have students research how deforestation impacts the carbon cycle and present findings to the class.

Key Vocabulary

photosynthesis	The process plants use to convert light energy, water, and carbon dioxide into chemical energy in the form of glucose (sugar) and oxygen.
chlorophyll	The green pigment found in plant cells that absorbs light energy, primarily red and blue wavelengths, needed for photosynthesis.
glucose	A simple sugar that is the primary product of photosynthesis, serving as food for the plant and a source of energy.
stomata	Small pores, usually on the underside of leaves, that allow for gas exchange (carbon dioxide in, oxygen out) and transpiration.