How to teach CER in middle school science

I got an email from a language arts teacher/coworker last week. She said she was using the CER (Claim Evidence Reasoning) framework for persuasive essays and asked if there is any common ground between our curricula. I nearly jumped for joy! CER is a technique for writing a lab conclusion in which students state their claim, provide the evidence supporting their claim, and then explain the reasoning that connects their evidence to their claim. CER is the best way for middle school students to structure their lab conclusions because it wraps lab evidence and science reasoning together with a claim. I love it because, when it’s used properly, CER forces students to make a claim and provide evidence that relates to it – skills that are noticeably absent in my 7th graders, especially this year. Here’s how I teach CER in my middle school science classroom.

What is a CER?

Claim, evidence, reasoning (CER) is a method of teaching critical thinking and scientific literacy that helps students to understand how to make and support scientific claims. The CER method involves three main components: a claim, evidence, and reasoning. A CER is a model for writing scientifically. In a CER, students must make a claim, justify their answer with data, and then connect the data with scientific reasoning. In language arts, this kind of writing is called persuasive writing.

The claim is the student’s answer to a question – what is the effect of mass on acceleration, or how do substances travel through a cell membrane.  It is simply a claim – no reasoning or explanation necessary. The claim is the “What I believe” portion of the CER. The claim is a statement that is being made about a scientific concept or phenomenon. It is a statement of what is believed to be true about a particular topic. For example, a claim might be that plants need sunlight to grow.

The evidence is the data that the students provides to support their claim – the measurements of acceleration taken on model racecars of two different masses or the observations of onion cells in salt water. The evidence provided can be qualitative or quantitative depending on the question being asked. In other words, the evidence is the “What I see” portion of the CER. Evidence is the data or information that is used to support the claim. This can include data from experiments, observations, or research studies. For example, evidence to support the claim that plants need sunlight to grow might include data from experiments showing that plants grown in a sunny location grow taller and have more leaves than plants grown in a shaded location.

The reasoning explains how or why the evidence supports the student’s claim – if a more massive racecar didn’t accelerate as fast as a lower mass racecar, then an increased mass reduces acceleration. If onion cells in salt water are shriveled, then water moves out through a cell membrane in hypertonic solutions. In other words, the reasoning is the “What it means” portion of the CER. The reasoning should include an explanation of the underlying science concept of the claim and evidence. Reasoning is the explanation of how the evidence supports the claim. It is the process of connecting the evidence to the claim and explaining why the evidence supports the claim. For example, the reasoning for the claim that plants need sunlight to grow might be that the energy from the sun is used by the plant to produce food through photosynthesis, which is essential for the plant’s growth.

The CER method can be used to teach students how to evaluate scientific information and to develop their own scientific arguments. By teaching students how to make claims, find evidence to support their claims, and reason about how the evidence supports their claims, teachers can help students to become more critical thinkers and to develop a deeper understanding of scientific concepts.

Additionally, the CER method can be used to help students to communicate their scientific understanding to others. By learning how to clearly state their claims, present evidence to support their claims, and explain their reasoning, students can effectively communicate their understanding of scientific concepts to others, which is an important skill for scientists and science students.

Introducing CER in middle school science

A commonly used CER introduction in middle school is the “My dad’s an alien” advertisement which you can see on Youtube by clicking here. In this fantastic example, a little girl makes the claim that her father is an alien. She has lots of evidence including the weird noises he makes while gargling and his strange clothes.  While this ad does a great job connecting a claim with evidence, the reasoning must be inferred – normal dads don’t make those weird noises or wear strange clothes so he must be an alien. It’s a great way to begin to teach CER in middle school science.

Present students with other CER examples and have them analyze each examples by identifying the claims, evidence, and reasoning.

Fun CERs to learn with

cer templateAfter students have analyzed sample CERs, introduce them to a CER template. Download a simple template here or create your own.

The easiest way to get students to learn and practice the format of a CER is by using non-science content. Find ideas that students have prior knowledge of to provide a low barrier of entry. Make it interesting so that students are motivated to make a claim. Here are some ideas:

What’s happening in this photo? Present students with an image and ask them what’s happening and how they know that it’s happening. For example, ask students what animal made these footprints:

polar bear footprints

A reasonable claim is that a polar bear made the footprints. The evidence that is observable is that the foot appears to have toes and that it is made in the snow. The reasoning a student might provide is that bears are the only animals that live in snowy areas have feet shaped like this.

Here’s another example of how to teach CER in middle school science:

Claim: These two people are at a Christmas party.

Evidence: They appear happy and there is confetti in the air. They are wearing Santa hats.

Reasoning. We know it is a party because people throw confetti and appear happy at parties. We know it is Christmas time because the people are wearing Santa hats which people only wear at Christmas time.

Is a hot dog a sandwich? Students will need to pick a side, yes or no, and then defend it. They will have to define what a sandwich is and then apply the definition to the their experience of a hot dog by using the CER format. One response might be:

  • Claim – Yes, hot dogs are sandwiches.
  • Evidence – Hot dogs are bread and a filling.
  • Reasoning – Sandwiches are made of bread and a filling.

Is salsa a soup? An example of a response could be:

  • Claim – No, salsa is not a soup.
  • Evidence – Salsa is not eaten with a spoon.
  • Reasoning – Soup is eaten with a spoon.

Which invention is more important – television or airplane flight?

Which sport is more popular – soccer or American football?

Should students learn cursive in school?


CER Science examples

Once you’ve introduced the format of a CER and students have had opportunities to practice with general knowledge, it’s time to introduce some science-based CERs. Start out with more accessible science topics before you advance to having students use the CER technique for more formal lab conclusions. These are more complicated than the general knowledge CER examples because students will have to use more complicated analytical thinking to support their claims. Here are some examples:

  • Vegetarian diets are healthier for you.
  • Chicken soup is a good remedy for a cold.
  • The space program isn’t worth how much money it costs.
  • Electric cars will become more common in the future.
  • Social media is harmful to students.
  • Vinegar repels mosquitoes.


Tips for Using CER in the Classroom

Here are some tips to make it easier to teach CER in middle school science:

  • Ask students to highlight their claim in yellow, their evidence in green, and their reasoning in blue. Not only will it help students ensure that they have the three required parts to their CER,  it will also make it easier for you to grade!
  • The reasoning part of the CER is the hardest part for students to master. Provide them with sentence stems such as:
    • “This evidence supports my claim because…”
    • “I know this is true because…”
    • “Therefore…”
    • “This is important because…”
    • “The evidence suggests that…”
    • “Based on the evidence, I can infer….”

free c-e-r template

When you teach CER in middle school science, you are using a powerful teaching tool that can help students to develop critical thinking and scientific literacy skills. By learning how to make claims, find evidence to support their claims, and reason about how the evidence supports their claims, students can develop a deeper understanding of scientific concepts and become more critical thinkers. Additionally, the CER method can be used to help students to effectively communicate their scientific understanding to others.


Claim Evidence Reasoning CER Writing Practice for Middle School Science

Published by JustAddH2OTeacher

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