What Makes Something Alive?

Overview

This opening lesson launches the five-part unit “Cells: The Units of Life.” Students classify familiar examples, identify patterns associated with life, and use observations as evidence to develop an initial claim about whether all living things are made of cells.

Learning intentions

Students will be able to:

• Identify characteristics commonly shared by living things.
• Classify familiar objects as living, nonliving, or uncertain using evidence.
• Record observations, questions, and evidence in a science table.
• Develop an initial claim about whether all living things are made of cells.
• Discuss ideas respectfully and respond to classmates’ evidence.

Success criteria

• I can classify an example and explain my reasoning.
• I can record specific observations rather than unsupported opinions.
• I can use evidence from examples to support an initial claim.
• I can ask a relevant question about cells and living things.

Curriculum links

• Cite specific textual or visual evidence to support analysis of science information.
• Follow a multistep procedure when completing a scientific recording task.
• Read and comprehend grade 6–8 science texts and captions.
• Participate effectively in collaborative discussions, building on others’ ideas.

Lesson structure (45 minutes)

1. 0–5 min · Hook and initial thinking. Open with the hook image and opening question showing a seed, a robot, a flame, a dog, and a crystal, and ask, “Which of these are alive, and what makes you think so?” Students independently choose one example and write a brief reason, then share with a partner.

2. 5–12 min · Build criteria for life. Use the characteristics-of-life teaching slides to introduce observable characteristics such as using energy, growing or changing, responding to the environment, reproducing, maintaining internal conditions, and being made of one or more cells. Emphasize that a single characteristic is not always enough to classify something as living. Students paraphrase two characteristics and identify one example for each in their notes.

3. 12–15 min · Model evidence recording. Display the evidence-table model and think aloud using a plant: “I observe new leaves forming, so I have evidence that it grows.” Distribute the living-or-nonliving evidence table. Students identify the difference between an observation, an inference, and a question before beginning group work.

4. 15–28 min · Group classification investigation. Organize students into groups of four and show the classification task and procedure. Students examine the examples pictured on the worksheet—such as a dog, tree, mushroom, fire, toy robot, cloud, and crystal—and classify each as living, nonliving, or uncertain. They record at least one specific observation, a characteristic of life connected to the evidence, and a question for any uncertain example. Assign roles: facilitator, recorder, evidence checker, and reporter; students rotate roles halfway through.

5. 28–37 min · Evidence discussion. Return to the discussion prompts. Groups compare one classification that was easy and one that was uncertain, citing evidence from their tables. Students listen for similarities and differences, use the frames “Our evidence is…” and “We agree/disagree because…,” and revise one classification if another group presents stronger evidence. Prompt students to consider whether fire, seeds, viruses, or robots meet all the criteria.

6. 37–42 min · Cells connection and initial claim. Show the cells connection and claim prompt: “Are all living things made of cells?” Explain that scientists use evidence from observations, investigations, and texts to develop and revise claims. Students write an initial claim on the worksheet and support it with one observation or idea from the lesson. Clarify that this is a starting claim to revisit as the unit develops, not a final answer.

7. 42–45 min · Exit check. Display the closing questions. Students complete the worksheet exit response: name one characteristic of life, classify one example, cite specific evidence, and write one question they have about cells. Collect worksheets as students leave.

Resources

• Computer and projector
• the What Makes Something Alive? slide deck
• the living-or-nonliving evidence table
• Pencils or colored pencils
• Visible timer
• Whiteboard or chart paper
• Four group role cards or displayed role labels
• Optional document camera for sharing student evidence

Assessment

• During group work, check whether students record observable evidence rather than statements such as “it just is.”
• Listen to discussions for accurate use of characteristics of life and respectful responses to classmates’ claims.
• Use the completed evidence table and exit response to identify students who can support a classification with evidence and students needing support distinguishing observations from inferences.

Differentiation

• Provide sentence starters: “I classify ___ as ___ because I observe ___,” “This evidence connects to ___,” and “I wonder whether ___.”
• Preteach and display key terms with simple visuals: living, nonliving, observe, evidence, characteristic, cell, and reproduce.
• Allow students who need support to complete fewer examples while maintaining the requirement for specific evidence; provide a partially completed model table or scribe support as appropriate.
• Challenge ready students to explain why one example is difficult to classify and to identify which additional evidence or investigation would help resolve the question.
• For multilingual learners, permit labeled sketches, partner rehearsal, and home-language discussion before sharing in English. Read slide text aloud and use high-contrast images for students with visual or reading needs.