Year 7 Science · AC9S7H01

How Scientific Knowledge Changes

Use evidence, models and perspectives to explain why scientific knowledge can be revised without becoming “just opinion”.

Part A — Accessible

  1. Explain why scientific knowledge can be reliable even though it may change.
  2. State one difference between evidence and interpretation.
  3. Why should one surprising result usually be repeated before changing an accepted explanation?
  4. Give one way improved technology can change scientific knowledge.

Part B — Standard

  1. Organisms A and B look similar, but DNA and fossil evidence show B is more closely related to C. Explain what scientists should reconsider and why.
  2. A community has long observed that a flowering event often occurs before a bird arrives. Explain how this perspective could contribute to scientific knowledge without replacing evidence.
  3. An old astronomy model predicts an eclipse incorrectly while a newer model predicts several eclipses accurately. What evidence would justify revising the model?
  4. Explain why an older scientific model can still be useful after a newer model is accepted.

Part C — Challenging

  1. A news headline says, “One experiment overturns everything scientists knew.” Evaluate this claim.
  2. Two explanations fit the current evidence equally well. What should scientists do next?
  3. Construct a four-step chain showing how new evidence can lead to revised scientific knowledge.
  4. Extended response: explain why evidence-based revision is a strength of science. Use one example from classification, astronomy, ecology or another suitable Year 7 context.

Answer key / marking guidance

1

Reliability comes from testing, repeated evidence and review. Explanations can be refined when stronger evidence appears.

2

Evidence is an observation or measurement; interpretation is what scientists infer or explain from that evidence.

3

Repeating helps check that the result is reliable and not caused by error or unusual conditions.

4

Improved instruments can reveal new details or provide more precise measurements that were previously unavailable.

5

Reconsider the relationship/classification because multiple independent evidence types indicate B is closer to C despite surface similarity.

6

The observation can guide a question or pattern study; scientists can compare dated flowering and bird-arrival records. The perspective helps direct attention, while evidence tests the relationship.

7

Repeated accurate predictions, better observations and stronger fit to evidence support revising the older model.

8

Older models may still explain many observations or show how understanding developed; useful parts can be retained in a refined model.

9

The claim is overstated. One experiment should be checked, replicated and compared with the wider evidence before a major revision.

10

Design further observations or tests that could distinguish between the explanations; compare predictions and explanatory power.

11

Example: existing explanation → new observation/evidence → repeat/check/compare → revised explanation better supported by evidence.

12

High-quality answers state that revision follows stronger evidence, not preference; explain checking/replication; use a correct example; and show how the revised explanation accounts for evidence better.