Claim-Evidence Writing
Learn
Scientists communicate their findings using claim-evidence-reasoning (CER) writing. This lesson teaches you how to write like a scientist about energy concepts.
The CER Framework
- Claim: A statement that answers a question or makes an assertion about energy
- Evidence: Data, observations, or facts that support your claim
- Reasoning: An explanation of how the evidence supports the claim using scientific principles
Why Use CER Writing?
CER writing helps you think clearly and communicate your ideas effectively. It is used in science classes, on standardized tests, and by real scientists!
Examples
Study these examples of claim-evidence-reasoning writing about energy.
Example 1: Strong CER Response
Question: Does a ball at the top of a ramp have more energy than a ball at the bottom?
Claim: A ball at the top of a ramp has more potential energy than a ball at the bottom of the ramp.
Evidence: When released from the top, the ball rolls down and gains speed, traveling across the floor. When placed at the bottom, the ball does not move on its own.
Reasoning: The ball at the top has gravitational potential energy due to its height. This potential energy converts to kinetic energy as the ball rolls down. The ball at the bottom has no height, so it has no gravitational potential energy to convert.
Example 2: Weak vs. Strong
Weak: "The ball moves because it has energy."
Strong: "The ball moves because it has kinetic energy. Evidence shows the ball traveled 2 meters after being pushed. This demonstrates that the push transferred energy to the ball, giving it motion."
✏️ Practice
Test your understanding with these practice questions.
Practice Questions
0/3 correctWhat is the scientific method's first step?
A hypothesis is:
Which is a property of matter?
Check Your Understanding
Answer these 10 questions about claim-evidence-reasoning writing.
1. What are the three parts of a CER response?
Answer: Claim (a statement that answers the question), Evidence (data or observations that support the claim), and Reasoning (explanation of how the evidence supports the claim).
2. Which of these is a good scientific claim about energy? A) "Energy is cool" B) "Heat energy transfers from hot objects to cold objects" C) "I think energy is important"
Answer: B) "Heat energy transfers from hot objects to cold objects" - This is a specific, testable statement about how energy works.
3. What makes evidence strong in scientific writing?
Answer: Strong evidence is specific (includes numbers or details), comes from observations or experiments, is relevant to the claim, and can be verified by others.
4. What is the purpose of the "reasoning" part of CER?
Answer: Reasoning explains WHY the evidence supports the claim by connecting it to scientific principles and concepts. It shows your understanding of the science.
5. Is this good evidence for the claim "A higher ramp gives a ball more energy"? Evidence: "The ball went far."
Answer: No, this is weak evidence. Better evidence would include specific measurements, such as "The ball traveled 50 cm from a 10 cm ramp but 95 cm from a 20 cm ramp."
6. Rewrite this weak claim as a strong claim: "The sun is hot."
Answer: Strong version: "The sun's thermal energy transfers to Earth through radiation, warming our planet" or "Solar energy from the sun provides heat and light energy to Earth."
7. What scientific principle should you include in reasoning about a bouncing ball losing height?
Answer: Energy transformation - specifically that some kinetic energy is converted to sound and heat energy when the ball hits the ground, so less energy remains for the bounce.
8. Why is "I believe" or "I think" usually not appropriate in scientific claims?
Answer: Scientific claims should be based on evidence and be testable, not on personal beliefs. A claim should be stated as a factual assertion that can be supported with evidence.
9. A student writes: "Light bulbs use energy." How could they improve this claim?
Answer: Make it more specific: "Light bulbs convert electrical energy into light energy and heat energy" - this explains what type of energy and what happens to it.
10. What is missing from this CER? "Claim: Solar panels produce electricity. Evidence: My house has solar panels and our electric bill went down."
Answer: The reasoning is missing. It should explain HOW solar panels work: "Solar panels convert light energy from the sun into electrical energy through special materials called photovoltaic cells. This electricity can power homes, reducing the need for electricity from the power company."
Next Steps
- Review any concepts that felt challenging
- Move on to the next lesson when ready
- Return to practice problems periodically for review