Energy in Ecosystems

Overview

In this 45-minute lesson, grade 3 students will explore how energy flows through local ecosystems. They will engage in a hands-on experiment to observe how plants convert sunlight into energy through photosynthesis and use this as a foundation to build a class food chain. This lesson builds on previous understanding of local ecosystems and supports students’ development of scientific inquiry and ecological awareness in alignment with the British Columbia Curriculum.

---

Curriculum Alignment

British Columbia Curriculum (Grade 3 Science) – Life Science

• Content: Investigate the needs of plants and animals and describe their roles in ecosystems.
• Big Ideas:
  • Living things are connected to their ecosystems and depend on their habitat to meet their needs.
  • Energy in ecosystems flows from the Sun through plants to animals.
• Core Competency Connections:
  • Communication: Share observations clearly with peers.
  • Thinking: Use inquiry to make sense of how energy is transferred in ecosystems.
  • Personal and Social: Work collaboratively and respectfully in group activities.

---

Learning Objectives

By the end of this lesson, students will be able to:

1. Explain that plants use sunlight to create energy (photosynthesis) in simple terms.
2. Demonstrate an understanding of energy flow in ecosystems by constructing a basic food chain.
3. Observe and record the outcome of a plant experiment related to light availability.
4. Communicate their observations using appropriate scientific vocabulary.

---

Materials Needed

• Clear plastic cups (one per student or pair)
• Bean seeds or fast-growing plants (e.g., cress)
• Potting soil
• Light source (natural sunlight or desk lamps)
• Paper and coloured pencils or markers
• Chart paper or whiteboard
• Photographs or illustrations of local animals (e.g., insects, birds)
• Simple Energy Flow Diagram handouts (optional)

---

Lesson Structure

1. Introduction (10 minutes)

• Begin with a brief review: “Last week, we talked about local ecosystems. Today, we’re going to find out how plants get their energy and how that energy moves through our ecosystem.”
• Use a questioning strategy: "Where do you think a plant gets its energy to grow?" Encourage answers to focus on sunlight.
• Introduce the word photosynthesis in simple terms: “It means plants make their own food using sunlight.”
• Show a very simple diagram or drawing of the Sun shining on a plant.

2. Experiment: Plants and Light (15 minutes)

• Group students in pairs and provide each with a plastic cup filled with soil and one seed planted inside.
• Explain the experiment: Some plants will be placed in sunlight, others in shade or under a lamp turned off, to observe how light affects their growth over time.
• Guide students to make initial observations and record what they see (size of the seed, colour of soil, etc.).
• Use guiding prompts: “What do you think will happen if the seed doesn’t get light?”
• Emphasise this is a long-term investigation but initial understanding will help them connect energy and life.

3. Food Chain Discussion (15 minutes)

• After the experiment set-up, return to the classroom circle for a discussion:
  • Ask, “If plants get energy from the Sun, who eats the plants?”
  • Use local ecosystem examples (e.g., grass → rabbit → fox).
• Create a collective food chain on the whiteboard or chart paper. Illustrate the flow of energy: Sun → Plant → Animal → Animal.
• Discuss how all living things depend on energy from the Sun indirectly or directly.

4. Wrap-up & Reflection (5 minutes)

• Invite students to share one new thing they learned about energy and ecosystems.
• Record student responses on chart paper under "Today’s Discoveries".
• Connect to next lesson: “Next time, we will explore different animals in our ecosystem and how they get their energy.”

---

Assessment

• Formative Assessment:

  • Observe student participation during the experiment and discussion.
  • Review recorded observations in their science journals or worksheets.
  • Listen to students’ explanations of the food chain and energy flow during the wrap-up.

• Success Criteria:

  • Students accurately describe plants’ need for sunlight to grow.
  • Students participate in constructing a simple food chain.
  • Students demonstrate curiosity and ask questions about energy in ecosystems.

---

Extensions & Enrichment

• Invite students to bring photos or drawings of their favourite local animals to add to the class food chain in future lessons.
• Start a class science journal to track the growth of the plants over the unit, encouraging daily or weekly observations.
• Incorporate a storytelling activity where students imagine being energy travelling from the Sun through different organisms.

---

Teacher Reflection Prompt

• Did students grasp the concept that energy originates from the Sun?
• How well did students collaborate during the experiment and discussion?
• Were students able to connect the experiment to the bigger idea of energy flow in ecosystems?
• What adaptations might improve engagement or understanding for future lessons?

---

This lesson uses inquiry and hands-on learning to deepen understanding of energy transfer in ecosystems, all while meeting Grade 3 British Columbia Science Learning Standards in an accessible, age-appropriate way.