Inside Every Living Thing

Overview

In this third lesson of the five-part unit Cells: The Units of Life, students examine microscope images, prepared slides, and digital models to identify patterns shared by plant, animal, and microbial cells. They use visual and written evidence to decide whether an object is made of cells and explain how observations support the idea that cells are the basic units of life.

Learning intentions

Students will be able to:

• Identify evidence that plant, animal, and microbial cells are living structures.
• Compare information from microscope images, prepared slides, digital models, and a short science text.
• Distinguish cellular organisms from non-cellular objects or images.
• Cite specific visual or textual evidence when explaining a claim.
• Discuss observations and conclusions respectfully with a partner or group.

Success criteria

• I can identify repeated cell-like structures in an image or model.
• I can record observations accurately in a table or diagram.
• I can compare plant, animal, and microbial cells using evidence.
• I can explain whether an object is cellular and support my explanation with specific evidence.

Curriculum links

• Integrating quantitative or technical information in text with visual representations such as diagrams, models, and tables.
• Following a multistep procedure when using slides, microscopes, or digital models.
• Comparing information gained from visual or digital sources with information gained from a written text.
• Citing specific evidence from science and technical texts to support analysis and participating in collaborative discussions.

Lesson structure (45 minutes)

1. 0–5 min · Hook and prediction. Display a striking microscope image beside an image of a grain of salt using the opening comparison slide and ask, “Which image shows something made of cells? What evidence would convince you?” Students make an individual prediction, then share one observation with a partner.

2. 5–11 min · Build background. Use the cell evidence and vocabulary slides to review that organisms are made of one or more cells and that cells are small structures with boundaries and internal parts. Students annotate a simple cell diagram and identify the difference between an observation (“I see repeated compartments”) and an inference (“It may be a cell”).

3. 11–15 min · Model the procedure. Demonstrate the four-step investigation: observe without guessing, record visible evidence, compare with the written description, and make a claim. Model how to use a prepared slide or digital image safely, including carrying equipment carefully, adjusting focus slowly, and recording the image label and magnification when provided. Students repeat the steps aloud with a partner before beginning.

4. 15–29 min · Cell evidence investigation. Distribute the cell comparison investigation sheet and, if available, provide prepared slides or station images for a plant cell, animal cell, and microbial cell. Students work in groups of three, rotating roles as observer, recorder, and procedure checker. At each station, they record at least two observations, sketch or label the visual, and note whether the evidence supports the claim that the sample is cellular. Students may use the cell organelle function cards as a reference while comparing visible or modeled structures.

5. 29–38 min · Compare sources and discuss. Show the short informational paragraph and corresponding diagrams on the source-comparison and discussion slides. Students compare what the text says with what the image or model shows, completing a claim-evidence-reasoning response on the worksheet. Groups discuss: “What do plant, animal, and microbial cells have in common?” and “Which evidence is strongest, and why?” Require students to refer to a specific station, diagram feature, or sentence from the text.

6. 38–45 min · Share and exit assessment. Invite two or three groups to share one supported claim and clarify any misconception, such as “all cells look alike” or “anything seen under a microscope is alive.” Students complete the final prompt on the conclusion and exit-ticket section: “Explain how one observation supports the idea that organisms are made of cells. Include one comparison between a cellular sample and a non-cellular object.” Collect responses before students leave.

Resources

• the cell evidence and comparison slide deck
• the cell comparison investigation sheet
• Prepared slides or printed microscope images of plant, animal, and microbial cells
• Student microscopes, if available
• Digital microscope images or cell models
• Prepared non-cellular comparison images, such as salt crystals or fibers
• Pencils and colored pencils
• the cell organelle function cards
• Safety glasses and microscope handling directions

Assessment

• During the investigation, check whether students follow the observation procedure, record evidence rather than guesses, and use the visual information accurately.
• Listen for evidence-based discussion. Ask students to point to the specific image feature or text statement supporting their claim.
• Use the exit response to assess whether students can distinguish cellular from non-cellular material, compare cell types, and cite specific evidence.

Differentiation

• Provide a word bank with terms such as cell, boundary, nucleus, membrane, organism, cellular, non-cellular, observation, and evidence. Offer sentence starters: “I observe…,” “The text says…,” and “This supports the claim because…”
• Pair students strategically and assign clear roles. Provide enlarged, high-contrast images and a partially completed comparison table for students who need reading, visual, or motor support.
• Allow students to use digital zoom, audio-supported text, or teacher-read directions. Check understanding after each procedure step, especially for English learners and students with executive-function needs.
• Challenge ready students to explain why a microbial cell may look simpler than a plant or animal cell while still meeting the definition of a cell, using evidence from at least two sources.