Supported pathway · Week 1 of 6
Scientific Thinking & Evidence
Build the reasoning habits needed for Integrated Science 9: distinguish observations from inferences, ask testable questions, identify variables, evaluate evidence, and construct explanations without claiming more than the evidence supports.
Why NAIB recommended this week
The readiness gateway uses strand evidence to identify prerequisite skills that would benefit from reinforcement. This week is support, not a penalty or replacement for the official course. Strong skills may be confirmed quickly; developing skills receive additional practice.
Learning objectives
- Separate direct observation from inference, prediction, opinion, and explanation
- Turn broad questions into measurable, testable scientific questions
- Identify independent, dependent, and controlled variables
- Distinguish evidence from a claim and reasoning that connects them
- Explain why correlation alone does not establish causation
- Describe model usefulness, assumptions, and limitations
- Revise an explanation when evidence does not support the original claim
Use supplied fictional scenarios. No personal health, household-risk, chemical, electrical, or biological experiments are required.
1 · Observation or inference?
An observation reports information obtained through measurement or appropriate senses/instruments. An inference interprets observations using prior knowledge or a model.
| Statement | Type | Why? |
|---|---|---|
| The liquid is blue. | Observation | A visible property is reported. |
| The liquid contains copper ions. | Inference/hypothesis without additional evidence | Color alone does not establish composition. |
| The temperature is 31.2 °C. | Measurement/observation | An instrument provides a quantitative value. |
| The reaction became faster because the particles had more kinetic energy. | Mechanistic explanation | It interprets observations using a model. |
Write two observations about a fictional graph and two inferences. For every inference, identify the observation that supports it.
2 · Make a question testable
A useful experimental question identifies measurable variables. “Does light affect plants?” is broad. “How does daily light duration affect mean seedling height after 14 days under otherwise matched conditions?” identifies what changes and what is measured.
Rewrite: “Which fertilizer is best?” and “Does heat matter?” so each identifies an independent variable, dependent variable, comparison, and measurement period.
3 · Variables and fair comparisons
The independent variable is deliberately changed; the dependent variable is measured as an outcome. Relevant controlled variables are held sufficiently consistent so competing explanations are reduced.
Two identical containers each receive 100 mL of water and the same mass of sugar. Container A is 20 °C and B is 50 °C. Dissolving time is recorded. Identify the independent variable, dependent variable, three controls, and one possible source of measurement uncertainty.
4 · Claim → Evidence → Reasoning
A claim answers a scientific question. Evidence is relevant data or observations. Reasoning explains why the evidence supports the claim using scientific principles.
| Light (h/day) | Mean seedling height (cm) |
|---|---|
| 0 | 2.0 |
| 2 | 2.6 |
| 4 | 3.4 |
| 6 | 4.1 |
| 8 | 4.3 |
Write one claim supported by this dataset, cite at least two values as evidence, and give reasoning. Then identify one stronger claim the data do not justify.
5 · Correlation is not automatically causation
When two measured variables change together, they are associated. Causation requires stronger evidence because hidden variables, reverse relationships, coincidence, selection effects, or measurement problems may create an apparent pattern.
A town records higher ice-cream sales on days with more swimmers at a public pool. Explain why the correlation does not show that ice cream causes swimming. Propose a third variable and one investigation that could clarify the relationship.
6 · Models help—and have limits
Scientific models represent selected features of systems so scientists can explain, predict, test, or communicate. A useful model is not required to be a perfect copy of reality. Its assumptions and omitted features matter.
Consider a ball-and-stick molecular model. Identify two features it represents usefully, two features it simplifies or distorts, and one scientific question for which a different model would be better.
Application · Mystery containers
Three sealed fictional containers are described only by measurements: mass, volume, temperature, and observations after identical external warming. Construct two competing explanations for the different temperature changes. List what the supplied evidence supports, what remains uncertain, and one additional measurement that would discriminate between the explanations.
Week 1 mastery evidence
Complete the following ten-item check without answer disclosure. Score 8/10 or higher and complete reasoning corrections for missed items before Week 1 is recorded as mastered.
- Classify “the solution has a pH of 5.2” as observation, inference, prediction, or opinion.
- Rewrite “Which soil is better?” as a testable question.
- Identify the independent variable in an investigation changing water temperature and measuring dissolving time.
- Identify the dependent variable in that investigation.
- Name one relevant controlled variable.
- Explain the difference between evidence and reasoning.
- Explain why correlation alone cannot establish causation.
- Give one plausible confounding variable in a fictional observational study.
- State one benefit and one limitation of a scientific model.
- Given a claim contradicted by new measurements, describe the scientifically appropriate next step.
NAIB Week 1 record
Record the strand as Scientific Practices with mastery percent, attempt number, correction status, strengths, and refresh priorities. This is a readiness/refresh record and must not overwrite a prior course-completion record.
Which scientific-thinking habit changed most this week? Give one example of an explanation you revised because the evidence required it.