Claim-Evidence Writing
Learn
Engineers must communicate their findings clearly and convincingly. In this lesson, you will learn how to write claims (statements about what your tests show) and support them with evidence (data from your experiments). This skill is essential for explaining why your design works.
The Claim-Evidence-Reasoning Framework
- Claim: A statement that answers a question or makes a conclusion about your design
- Evidence: Specific data or observations from your tests that support your claim
- Reasoning: An explanation of how your evidence supports your claim, using scientific ideas
Writing Strong Claims
- Be specific and clear
- State what you found or concluded
- Avoid vague language like "it was good"
- Make sure your claim can be supported with data
Using Evidence Effectively
- Use specific numbers and measurements
- Reference your test results directly
- Include enough evidence to be convincing
- Only use evidence that actually supports your claim
Examples
Work through these examples to see claim-evidence-reasoning in action.
Example: Writing About a Bridge Test
Test Data: Three bridge designs were tested. Bridge A held 12 pounds, Bridge B held 8 pounds, Bridge C held 15 pounds.
Weak Claim: "Bridge C was the best."
Strong Claim: "Bridge C was the strongest design because it held the most weight before breaking."
Evidence: "In our tests, Bridge C held 15 pounds, which was 3 pounds more than Bridge A (12 pounds) and 7 pounds more than Bridge B (8 pounds)."
Reasoning: "The triangular supports in Bridge C distributed the weight more evenly across the structure, preventing any single point from bearing too much stress."
✏️ 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
Test yourself with these review questions. Click each question to reveal the answer.
1. What is a claim in scientific writing?
Answer: A claim is a statement that answers a question or makes a conclusion based on evidence. It tells what you found or what you think is true based on your data.
2. What is the difference between evidence and reasoning?
Answer: Evidence is the specific data or observations from your tests. Reasoning explains HOW that evidence supports your claim, often using scientific concepts to make the connection clear.
3. Why is "My design was good" a weak claim?
Answer: This claim is weak because it is vague. It does not explain what "good" means, what the design accomplished, or what evidence would prove it was good. A strong claim would be specific and measurable.
4. What makes evidence strong?
Answer: Strong evidence is specific (uses numbers and measurements), comes directly from your tests, is relevant to your claim, and can be verified by others who look at your data.
5. A student claims: "Design B is faster than Design A." What evidence would support this claim?
Answer: Evidence could include specific times from tests, such as "Design B completed the course in 12 seconds, while Design A took 18 seconds." The evidence must show a comparison of speed using measurements.
6. Why do engineers need to write about their findings?
Answer: Engineers write about their findings to share what they learned with others, explain why their design works, convince people to use their solutions, and create a record that helps future engineers build on their work.
7. What should you do if your evidence does not support your original claim?
Answer: You should revise your claim to match what the evidence actually shows. Scientists and engineers must be honest about their results, even when they are not what was expected.
8. How many pieces of evidence should you include to support a claim?
Answer: You should include enough evidence to be convincing, usually at least two or three pieces. More evidence makes your claim stronger, but all evidence must be relevant and from reliable tests.
9. What is the purpose of reasoning in a claim-evidence-reasoning statement?
Answer: Reasoning explains the connection between your evidence and your claim. It shows your thinking and uses scientific ideas to explain WHY the evidence supports what you are claiming.
10. Rewrite this weak claim to make it stronger: "The tall tower was better."
Answer: A stronger claim would be: "The tall tower design was more stable because it did not fall over when tested with wind from three different directions." This is specific about what "better" means and how it was tested.
Next Steps
- Review any concepts that felt challenging
- Move on to the next lesson when ready
- Return to practice problems periodically for review