Year 8 Science · Unit 1 · Lesson 19
Challenge Worksheet
Learning Goals
Find the mistake
Read the student biology explanation below carefully. It contains four errors in how evidence is used and how claims and reasoning are constructed. Find all four, then answer the questions on the next page.
A student wrote this explanation
Question: How does exercise affect breathing rate?
Paragraph 1: "My investigation showed that breathing rates were 14, 24 and 17. These numbers are the evidence. This proves that exercise is the most dangerous activity a human can do."
Paragraph 2: "Plants given more light grew taller. This shows that water is the most important input for plant growth."
Paragraph 3: "A living system is a system that is living. Evidence: plants live. Reasoning: because they are alive."
Paragraph 4: "Both plants and animals are living systems. This is a strong scientific claim because it is true."
1. Identify all four errors. For each, state which paragraph it is in and describe what is wrong, focusing on whether the Claim, Evidence, or Reasoning part of the CER framework has a problem.
2. Rewrite Paragraph 1 correctly using CER format. Your rewrite must include a proper Claim (what the data shows), Evidence (specific numbers from the table), and Reasoning (why the pattern makes sense for a living system).
1. Paragraph 4 says: "This is a strong claim because it is true." Explain why "being true" is not enough to make a scientific claim strong. What does a strong claim also need, according to the lesson's CER framework?
2. The lesson uses a breathing-rate table as an example of how to interpret data rather than just copy it. Write a short explanation of the difference between "copying" and "interpreting" using this example. Why does interpreting make for a stronger scientific explanation?
Wrap Up
In one sentence, why must evidence-based explanations include reasoning and not just data values?