Year 9 Science · Unit 4 · Lesson 19
Apply Worksheet
Learning Goals
Compare two
Complete the table to compare primary evidence and secondary evidence in a waves and motion investigation. Fill in both columns for each feature.
| Feature | Primary evidence | Secondary evidence |
|---|---|---|
| Who collects it? | ||
| One example from a speed/ramp investigation | ||
| One example from a waves investigation | ||
| Key advantage | ||
| Key limitation |
Investigation scenario
A Year 9 student wants to claim: "Doubling the ramp angle doubles the speed of a toy car." They have collected 3 trials at only two ramp angles — 20° and 40° — and measured the car's speed at the bottom of the ramp. The average speed at 20° was 0.8 m/s and at 40° was 1.3 m/s.
(a) Is the evidence strong enough to support the student's claim that "doubling the ramp angle doubles the speed"? Explain your reasoning using the data provided.
(b) Describe two specific changes to the investigation that would strengthen the conclusion. Explain why each change improves the evidence.
(c) How does the CER (Claim–Evidence–Reasoning) framework help distinguish between a claim and a conclusion supported by evidence? Use this investigation as your example.
Wrap Up
In one sentence, what is the most important thing that separates a scientific claim from a scientific conclusion?