AC9S10I02: Design Valid, Reproducible Investigations

A strong plan aligns variables, controls, sampling, risk, ethics and cultural responsibilities with the question.

By the end of this lesson, you should be able to:

• Validity depends on alignment and control of relevant variables.
• Reproducibility requires transparent procedures and useful sample sizes.
• Risk, ethics and Country/Place protocols can change or prevent a method.

Students should identify variables, write a repeatable method, recognise hazards and distinguish validity from simply obtaining a result.

Learning sequence: Align the design → Control confounding factors → Plan useful data → Complete responsibility checks

Core teaching

• Validity depends on alignment and control of relevant variables.
• Reproducibility requires transparent procedures and useful sample sizes.
• Risk, ethics and Country/Place protocols can change or prevent a method.

Key vocabulary and ideas

• question
• variables and controls
• sampling and repeats
• risk and ethics
• reproducible method

• Many repeats fix systematic bias: Use calibration and design changes for bias; repeats mainly estimate random variation.
• A detailed method is automatically valid: Check whether the evidence can actually answer the question.

Keep the Year 10 boundary: Do not treat repetition as a cure for every design problem. Do not access heritage material, sites or knowledge without correct authority and protocols.

1. Audit a motion investigation for confounding variables, calibration and sample size.
2. Rewrite the three weakest steps.

Work through the sequence Align the design → Control confounding factors → Plan useful data → Complete responsibility checks, explaining the evidence or mechanism at each step before moving on.

1. A method changes temperature and concentration at the same time. Explain why this threatens validity and propose a correction.
2. Identify two features that make a written method reproducible by another investigator.
3. For a school investigation, distinguish a hazard from a risk-control measure and give one example of each.
4. Explain why ethical requirements or cultural protocols may require a method to be changed even if it is scientifically workable.

Critique an investigation where two variables change at once, the sample is small and measurements are rounded heavily. Prioritise the design fixes that matter most for validity and reproducibility.

Reasoning standard: state the claim, use relevant evidence or a scientific mechanism, and explain why the evidence supports the conclusion without overclaiming.

What is the central idea?

A strong plan aligns variables, controls, sampling, risk, ethics and cultural responsibilities with the question.

What should a strong response do?

Use the sequence Align the design → Control confounding factors → Plan useful data → Complete responsibility checks. Connect the evidence, mechanism or data to the claim.

What common trap should I avoid?

Many repeats fix systematic bias: Use calibration and design changes for bias; repeats mainly estimate random variation.

1. Critique an investigation with one trial, an uncontrolled temperature, vague measurement instructions and no risk assessment. Prioritise four improvements and justify each one.
2. Design a valid, reproducible investigation to test how surface area affects reaction rate. Include variables, controls, repeats, measurement, risk controls and a method for recording data.
3. An investigation would involve access to a heritage site on Country/Place. Explain the scientific, ethical and cultural considerations that must be addressed before data collection begins.

Review hint: Use precise scientific vocabulary, show the relevant mechanism or evidence, and state any limitation or uncertainty when the evidence does not justify a stronger claim.

• I can explain and apply: Validity depends on alignment and control of relevant variables.
• I can explain and apply: Reproducibility requires transparent procedures and useful sample sizes.
• I can explain and apply: Risk, ethics and Country/Place protocols can change or prevent a method.

Exit ticket: Explain the core idea in 3–5 sentences and apply it to one new example without copying the worked model.

Australian Curriculum v9.0 — AC9S10I02: plan and conduct valid, reproducible investigations to answer questions and test hypotheses, including identifying and controlling for possible sources of error and, as appropriate, developing and following risk assessments, considering ethical issues, and addressing key considerations regarding heritage sites and artefacts on Country/Place

Victoria — VC2S10I02, Levels 9–10: Levels 9–10 valid investigations, control of variables, risk, ethics and bias considerations. Victorian Science is banded across Levels 9 and 10, so the VC2S10 code identifies the band rather than a single school year.

NSW: Stage 5 Working scientifically — designs and conducts safe, ethical, valid and reliable investigations (SC5-WS-03, SC5-WS-04). Where NSW places the closest concept in another Stage or spreads it across focus areas, this page states that relationship rather than claiming a false one-to-one Year 10 equivalent.

Use these links to move through the learning sequence rather than studying this code in isolation.

• AC9S10I01
• AC9S10I03

• Australian Curriculum v9.0 — Science
• Victorian Curriculum F–10 Version 2.0 — Science
• NSW Science 7–10 Syllabus (2023) — outcomes

Curriculum equivalents for Plan and conduct valid, reproducible investigations to answer questions and...

Mapped skill: plan and conduct valid, reproducible investigations to answer questions and test hypotheses, including identifying and controlling for possible sources of error and, as appropriate, developing and following risk assessments, considering ethical issues, and addressing key considerations regarding heritage sites and artefacts on Country/Place

These references identify matching or closely related learning. Curriculum sequence, terminology and depth vary, so teachers should use the mapped skill and lesson difficulty to confirm suitability.

Australian Curriculum v9.0 is the canonical source for this SkillrHub lesson. Victoria and NSW entries name the closest published state codes or outcomes; international entries are planning references rather than claims of identical curricula.