Science · Year 2 · Working Scientifically · Summer Term

Planning Simple Investigations

Learning to plan simple comparative and fair tests to answer scientific questions.

• National Curriculum Attainment Targets
• KS1: Science - Working Scientifically

About This Topic

Planning simple investigations teaches Year 2 pupils to design comparative and fair tests that answer scientific questions. They practise identifying what to change, keep the same, and measure, for example when testing which paper towel is most absorbent. Pupils learn to explain why only one variable changes at a time and critique plans for fairness, directly aligning with KS1 Working Scientifically standards.

This skill anchors the scientific process, building habits of precision and logical thinking. Within the Summer Term unit, it connects to practical enquiries across plants, animals, and materials, helping pupils see investigations as structured problem-solving rather than random trials. Regular practice strengthens their ability to predict outcomes and justify methods.

Active learning suits this topic perfectly because pupils gain ownership through hands-on planning and immediate testing. Collaborative critiques reveal flaws in real time, while group trials encourage adjustments based on evidence, making abstract fairness concepts concrete and memorable.

Key Questions

1. Design a fair test to see which paper towel is most absorbent.
2. Explain why it's important to change only one thing in an experiment.
3. Critique a simple investigation plan for fairness.

Learning Objectives

• Design a fair test to compare the absorbency of different paper towels.
• Explain why controlling variables is essential for a fair test.
• Identify the independent, dependent, and controlled variables in a simple investigation plan.
• Critique a given investigation plan for fairness, suggesting specific improvements.

Before You Start

Observing and Describing Materials

Why: Students need to be able to observe and describe properties of materials, like absorbency, before they can plan to test them.

Asking Scientific Questions

Why: The ability to formulate a question that can be investigated is a fundamental step before planning an experiment.

Key Vocabulary

Fair Test	An experiment where only one factor is changed at a time, so you can be sure that factor is causing the result you see.
Variable	Anything that can be changed or kept the same in an experiment. There are things to change, things to measure, and things to keep the same.
Independent Variable	The one thing that the scientist deliberately changes in an experiment to see what effect it has.
Dependent Variable	The thing that is measured or observed in an experiment; it is expected to change in response to the independent variable.
Controlled Variable	All the things that are kept the same in an experiment to ensure that the test is fair.

Watch Out for These Misconceptions

Common Misconception

Fair tests need everything exactly the same, even the question.

What to Teach Instead

Pupils must change one variable purposefully while controlling others to isolate effects. Active group critiques help them spot this by comparing plans aloud, leading to clearer variable lists through peer discussion.

Common Misconception

More changes make results more interesting.

What to Teach Instead

Multiple changes confuse causes, so fair tests isolate one factor. Hands-on mini-trials show messy data from uncontrolled variables, prompting pupils to redesign collaboratively for reliable outcomes.

Common Misconception

Plans do not need repeats or measurements.

What to Teach Instead

Repeats ensure reliability, and measurements provide evidence. Role-playing flawed tests in pairs highlights unreliable results, building understanding through trial-and-error adjustments.

Active Learning Ideas

Pairs: Paper Towel Test Planner

Pupils in pairs brainstorm a fair test for paper towel absorbency: list brands to compare, measure water drops absorbed, control towel size and water volume. They draw labelled steps and predict results. Pairs present to class for quick feedback.

30 min·Pairs

Small Groups: Ramp Speed Critique

Groups review a flawed plan for testing toy car speeds on ramps, spot uncontrolled variables like car weight or push strength. They rewrite for fairness, test briefly, and note improvements. Share revisions on whiteboard.

45 min·Small Groups

Whole Class: Fair Test Gallery Walk

Display pupil-drawn plans for a plant growth test. Class walks around, uses sticky notes to critique fairness and suggest changes. Vote on best plan, then trial it together to check predictions.

40 min·Whole Class

Individual: My Variables Chart

Each pupil completes a chart for a soap bubble test: one change (soap amount), same factors (water volume, bowl size), measure (bubble size). They self-check against success criteria before partnering to refine.

25 min·Individual

Real-World Connections

• Product developers at companies like Bounty or Plenty design and test new paper towels, changing factors like ply or texture to see which is most absorbent before they go to market.
• Food scientists testing new recipes might change only the amount of one ingredient, like sugar, while keeping all other ingredients and baking times the same to see how it affects the final taste or texture.

Assessment Ideas

Quick Check

Present students with a scenario: 'Sarah wants to test which brand of biscuit is crunchiest. She uses a different amount of milk to dunk each biscuit. What is wrong with her test? What should she do differently?'

Discussion Prompt

Ask students: 'Imagine we are testing which toy car rolls fastest down a ramp. What are three things we MUST keep the same for a fair test? What is the ONE thing we will change?'

Exit Ticket

Give each student a card with a simple investigation plan, e.g., 'To test which plant grows tallest, I will give Plant A 100ml of water and Plant B 200ml of water.' Ask them to write one sentence explaining why this test is not fair.

Frequently Asked Questions

How to teach fair testing to Year 2 pupils?

Start with familiar questions like paper towel absorbency. Model variable identification on the board: change brand, same water drops and time. Pupils practise in pairs, test quickly, and discuss why controls matter. Use visuals like traffic lights for fair/partial/unfair checks to reinforce daily.

What activities build planning skills in KS1 science?

Incorporate pair planning for everyday tests, such as ramp speeds or bubble sizes. Follow with group critiques and short trials to test plans. Chart templates guide variable sorting, while gallery walks encourage peer feedback, turning planning into a shared, iterative process.

Common errors in Year 2 investigation plans?

Pupils often overlook controls or add extra changes. They skip repeats or vague measurements. Address through modelled examples and checklists. Quick partner reviews catch issues early, with class trials showing how errors lead to unclear results and motivating precise redesigns.

How does active learning support planning investigations?

Active approaches like pair brainstorming and group trials make fairness tangible: pupils see flawed plans fail firsthand, spurring refinements. Collaborative critiques build vocabulary for variables, while shared testing fosters resilience. This beats worksheets alone, as real outcomes deepen understanding and excitement for scientific method.