CER in Bio-Lab

Overview

Students learn the Claim, Evidence, Reasoning (CER) framework and apply it to a short biology lab scenario to strengthen scientific writing. This lesson builds toward later lab notebook entries by helping students move from observations to well-organized written explanations.

Learning intentions

• Students will be able to identify the difference between a claim, evidence, and reasoning in a science response.
• Students will be able to write a CER entry for a bio-lab question using accurate evidence from provided data.
• Students will be able to include logical reasoning that connects evidence to the claim.
• Students will be able to revise their CER using clarity and cohesion strategies.

Success criteria

• I can write a clear claim that answers the lab question.
• I can select relevant evidence from the data (not just restate observations).
• I can write reasoning that explains how the evidence supports the claim.
• I can organize my CER so readers can follow the claim → evidence → reasoning chain.

Curriculum links

• CCSS.ELA-LITERACY.WHST.6-8.1a: Introduce claim(s), acknowledge and distinguish from alternate or opposing claims, and organize reasons and evidence logically.
• CCSS.ELA-LITERACY.WHST.6-8.1b: Support claims with logical reasoning and relevant, accurate data and evidence from credible sources.
• CCSS.ELA-LITERACY.WHST.6-8.1c: Use words, phrases, and clauses to create cohesion and clarify relationships among claim(s), counterclaims, reasons, and evidence.
• CCSS.ELA-LITERACY.RST.6-8.8: Distinguish facts, reasoned judgment based on research findings, and speculation.

Lesson structure (50 minutes)

1. 0–5 min · Launch & purpose. Teacher posts a sample lab notebook paragraph and asks, “What is the answer, what is the data, and what is the explanation?” Students do a quick think-write identifying each part.

2. 5–12 min · Direct teach: CER parts. Teacher explains CER using the class examples:

• Claim = answer to the question
• Evidence = data/observations from the lab or dataset
• Reasoning = scientific explanation connecting evidence to the claim Students annotate a second example with labels “C,” “E,” and “R.”

3. 12–20 min · Mini-lesson on logic and accuracy. Teacher models what counts as evidence versus speculation, referencing that students should distinguish facts from reasoned judgment and avoid unsupported claims. Students sort 8 sentence cards into “Claim,” “Evidence,” or “Reasoning” and justify one choice to a partner.

4. 20–35 min · Guided practice CER writing. Teacher distributes a one-page bio-lab scenario with a small table (e.g., temperature vs. time to color change for a catalyst enzyme model, or light intensity vs. rate of algae oxygen production). Teacher prompts the lab question on the board. Students write a CER response in their lab notebooks using a template:

• Claim: I think/because…
• Evidence: In our data, … (include two numbers or observations)
• Reasoning: This shows… because… Teacher circulates and checks for: claim matches the question, evidence is from the table, reasoning connects evidence to science principles.

5. 35–43 min · Add cohesion + a counterpoint (short). Teacher introduces sentence frames that connect parts and clarify relationships (e.g., “The data show…, therefore…” and “Some might argue…, but…”). Students revise their CER by adding one cohesion phrase and a brief alternate view sentence (1–2 lines) that they address respectfully (even if they disagree).

6. 43–48 min · Peer review with a checklist. Teacher gives a quick rubric/checklist:

• Claim is clear and answers the question
• Evidence is specific and accurate
• Reasoning explains the connection
• Writing is organized with clear transitions Students swap notebooks, read, and leave one “Glow” (strength) and one “Grow” (next step).

7. 48–50 min · Exit ticket. Students respond to a single prompt: “Write one sentence that begins with ‘Evidence shows… therefore…’ and completes a reasoning link to your claim.”

Resources

• CER template printout (or notebook chart)
• Bio-lab scenario handout with small data table/graph
• Example CER paragraphs (2–3 versions, one with mistakes)
• Sentence card sort set (Claim/Evidence/Reasoning)
• Peer review checklist (4 items)
• Student lab notebooks and pens/pencils
• Timer for transitions

Assessment

• Teacher observation during guided practice: accuracy of claim, specificity of evidence, and presence of reasoning
• Peer review checklist: identify at least one CER element missing or unclear
• Exit ticket sentence: ensures students can create an evidence-to-reasoning connection

Differentiation

• Provide sentence starters and a fill-in template for students who need structure (e.g., “My claim is…,” “The evidence is…,” “This supports my claim because…”).
• Offer an “evidence bank” (highlighted values from the data table) so students focus on selecting relevant evidence.
• For advanced writers, require stronger reasoning by asking for a second scientific link (e.g., cause-effect mechanism or variable relationship) and a clearer counterpoint sentence.
• For EAL/SEN support, allow oral rehearsal with a partner before writing, and encourage using the same transition starters across CER sections to reduce cognitive load.