Science · Year 6 · Working Scientifically: The Grand Investigation · Summer Term

Evaluating and Improving Investigations

Reflecting on the investigation process, identifying limitations, and suggesting improvements to ensure fair testing and accurate results.

• National Curriculum Attainment Targets
• KS2: Science - Working scientifically

About This Topic

Evaluating and improving investigations builds essential Working Scientifically skills for Year 6 students. They reflect on their experimental processes, identify limitations such as uncontrolled variables, small sample sizes, or measurement errors, and suggest practical improvements for fairer tests and more accurate results. This aligns with National Curriculum expectations to critique methodologies and predict outcome changes.

Students apply these skills across units, from fair testing in forces to data analysis in living things. By questioning fairness and accuracy, they develop critical thinking and evidence-based reasoning, preparing them for secondary science where experimental design is key. Group discussions reveal how minor changes, like increasing repeats or standardising conditions, enhance reliability.

Active learning excels in this topic because students actively critique real investigations. Peer reviews of classmates' workbooks or redesigning flawed setups in pairs uncover blind spots and build ownership. Hands-on iterations make abstract evaluation concrete, boosting confidence and retention of scientific habits.

Key Questions

1. Evaluate the fairness and accuracy of experimental results.
2. Critique the methodology of an investigation and suggest improvements for a fairer test.
3. Predict how changes to an experiment might alter the outcomes.

Learning Objectives

• Critique the methodology of a Year 6 investigation, identifying at least two uncontrolled variables.
• Evaluate the accuracy of experimental results by comparing them to expected outcomes or class averages.
• Propose specific, measurable improvements to an investigation's design to ensure a fairer test.
• Predict how a change in one experimental variable might affect the outcome based on prior investigation data.

Before You Start

Planning Investigations

Why: Students need prior experience in designing and conducting simple investigations to be able to critique and improve them.

Identifying Variables

Why: Understanding the concepts of independent, dependent, and control variables is fundamental to evaluating the fairness of a test.

Collecting and Recording Data

Why: Students must be able to gather and organize data before they can evaluate its accuracy or reliability.

Key Vocabulary

fair test	An investigation where only one variable is changed at a time, while all other conditions are kept the same, to ensure accurate results.
variable	A factor or condition that can be changed or kept the same during an experiment. This includes independent, dependent, and control variables.
control variable	A factor that is kept the same throughout an investigation to ensure that only the independent variable affects the dependent variable.
reliability	The consistency of results. An investigation is reliable if repeating it produces similar outcomes.
accuracy	How close a measurement or result is to the true or accepted value.

Watch Out for These Misconceptions

Common Misconception

A fair test requires perfect control of all variables every time.

What to Teach Instead

Real experiments have some variation; fair testing means controlling key variables while acknowledging others. Peer reviews help students discuss realistic limits and prioritise changes, building nuanced understanding through shared examples.

Common Misconception

More repeats always make results accurate without checking data quality.

What to Teach Instead

Repeats improve reliability only if measurements are precise. Group critiques reveal poor data collection, like inconsistent timing, prompting students to refine methods collaboratively.

Common Misconception

Improved results mean the original investigation was worthless.

What to Teach Instead

All investigations teach through reflection. Class redesign activities show iterative science in action, helping students value critique as progress, not failure.

Active Learning Ideas

Peer Review Carousel: Critique Partners

Pairs swap investigation lab books from a recent experiment. They use a checklist to note strengths, limitations, and three improvements, then discuss with the owner. Rotate partners for second reviews.

30 min·Pairs

Flawed Setup Fix-Up: Small Group Challenge

Provide groups with descriptions of three investigations with errors, like uneven heating or biased samples. Groups identify issues, suggest fixes, and predict improved outcomes. Present to class.

45 min·Small Groups

Gallery Walk: Whole Class Share

Students post investigation posters with results. Class walks around, sticking improvement Post-its. Debrief as whole class on common themes and redesign one example together.

35 min·Whole Class

Variable Tweak Prediction: Individual Think-Pair-Share

Individuals predict how changing one variable affects results in a familiar test. Pairs compare predictions, then share evidence-based improvements with small groups.

25 min·Pairs

Real-World Connections

• Food scientists at major supermarkets evaluate new product recipes by conducting controlled trials. They adjust ingredients (independent variable) while keeping cooking times and temperatures constant (control variables) to ensure the taste and texture are consistently excellent.
• Engineers designing new car brakes test their effectiveness by varying brake pressure (independent variable) under controlled conditions like road surface and speed (control variables). This ensures the brakes perform reliably and safely across different situations.
• Medical researchers conduct clinical trials to test new medicines. They carefully control patient groups, dosage, and other factors to accurately measure the drug's effect (dependent variable) and ensure patient safety.

Assessment Ideas

Peer Assessment

Students review a classmate's completed investigation write-up. Provide a checklist: 'Did they identify the independent, dependent, and at least two control variables? Did they explain why the test was fair? Did they suggest one specific improvement?' Students provide written feedback based on the checklist.

Exit Ticket

Present students with a brief description of a flawed investigation (e.g., testing plant growth with different amounts of water but also different amounts of sunlight). Ask: 'What made this investigation unfair? Suggest one change to make it a fair test.'

Quick Check

Show students a graph of experimental results. Ask: 'Do these results look reliable? Why or why not?' Follow up with: 'If you repeated this experiment, what is one thing you would do differently to get more accurate results?'

Frequently Asked Questions

How do I teach Year 6 students to evaluate investigations?

Start with familiar experiments, like paper helicopter drops. Model a critique using a think-aloud: identify variables, fairness issues, and fixes. Provide checklists for variables, repeats, and accuracy. Follow with peer reviews where students apply the process to each other's work, then redesign one element. This scaffolds independence while linking to curriculum standards.

What are common limitations in Year 6 investigations?

Students often overlook uncontrolled variables, such as room temperature in plant growth tests, or insufficient repeats leading to outliers. Measurement errors from imprecise tools also arise. Address these through whole-class data analysis sessions, graphing results to spot anomalies, and targeted improvements like standardised procedures.

How can active learning help students evaluate investigations?

Active approaches like peer critique carousels and group redesign challenges engage students directly with real data. Swapping lab books exposes diverse errors they might miss alone, while collaborative fixes build consensus on fair testing. These methods make evaluation social and iterative, deepening understanding and enthusiasm for scientific habits over passive worksheets.

How to assess evaluating and improving investigations?

Use rubrics scoring identification of limitations (1-4), suggestion quality, and prediction justification. Collect annotated lab books or recorded discussions. Oral presentations of improvements show reasoning depth. Align with Working Scientifically objectives by noting progress in fair test critiques across units.