How to Teach CER Writing in Science: Simple Strategies for Middle and High School Teachers

Melissa
Dec 8, 2025
3 min read

Updated: Jan 6

If you’ve ever asked your students to explain their scientific thinking and received blank stares or one-sentence answers, you’re not alone. CER writing in science (Claim, Evidence, Reasoning) is a powerful strategy, but it can feel overwhelming to teach—especially when you’re balancing content, labs, and everything else on your plate.

The good news? You can successfully teach Claim Evidence Reasoning in science without rewriting your entire curriculum. With the right structure and supports, your students can learn how to write strong CER responses with confidence.

Teacher assisting student writing in class.

How to Teach CER Writing in Science Step by Step

When students struggle with Claim Evidence Reasoning, it’s usually because they’re being asked to master all three parts at once. Scaffolding makes CER writing more manageable.

Try this simple progression:

Start with writing a clear scientific claim
Then practice finding text-based or data-driven evidence
Finally, teach students how to write scientific reasoning that connects their evidence to the claim

🛠️ Teacher Toolkit: Have students color-code their work using colored pens or highlighters: Claim = blue, Evidence = green, Reasoning = yellow. This makes CER structure visually clear and strengthens understanding.

CER Sentence Starters That Help Students Write Stronger Responses

CER sentence starters are one of the most effective tools for teaching science writing.

They are especially helpful for:

Struggling writers
English Language Learners (ELLs)
Students new to Claim Evidence Reasoning

Use these examples in your classroom:

Claim sentence starters:

“I claim that…”
“The data shows that…”

Evidence sentence starters:

“One piece of evidence is…”
“According to the text/data…”

Reasoning sentence starters:

“This proves my claim because…”
“This evidence matters because…”

Over time, you can slowly remove these supports as students gain independence.

🧠 Pro Tip: Post sentence starters on anchor charts or slide decks so students can reference them without asking for help.

Why Background Passages Improve CER Writing in Science

Many students struggle with CER writing in science because they don’t know what evidence to use. A short background passage, data table, or diagram gives students something concrete to reference.

Before assigning a CER response:

Provide a short science reading or visual
Model how to pull evidence
Show how that evidence becomes a claim

This strengthens both reading comprehension and scientific writing skills.

⚡ Quick Tip: Use short articles, data tables, graphs, or diagrams so every student has clear, usable evidence.

Teacher holding a piece of paper with a graph and pointing to the data, demonstrating how to interpret results in a science lesson.

Teaching Claim Evidence Reasoning Using “I Do, We Do, You Do”

The I Do, We Do, You Do model is one of the best ways to teach CER writing in science. This structure prevents student's frustration and builds confidence.

I Do: Model a complete CER response while thinking out loud.

We Do: Write a CER together as a class, guiding students through each step.

You Do: Start with group CER writing, then move to independent student responses.

🔍 Think Deeper: Ask students, “Why does this evidence matter in the real scientific world?” instead of “What is your evidence and reasoning?”

For Teachers Feeling Overwhelmed by CER Writing

If teaching CER writing in science feels overwhelming, you are not alone.

You don’t need perfect lessons or elaborate rubrics.

Start small:

One scaffolded CER question per unit
One set of CER sentence starters
One modeled class example

Small steps lead to real growth.

Final Thoughts: Helping Students Master CER Writing in Science

Teaching Claim Evidence Reasoning doesn’t have to feel stressful. With clear scaffolding, sentence starters, and gradual release, your students can learn to write like scientists—and you can feel confident teaching them.

If you’d like ready-to-use CER templates, science passages, and classroom-ready resources, explore the tools and strategies available here on Science With Ms. G. Try one small idea this week—you’re making a bigger impact than you think.