Friction Investigation

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Enquiry questions

How does the surface affect how far a toy car travels?

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Concepts

This study delivers 1 primary concept and 1 secondary concept.

Primary concept: Contact and Non-Contact Forces (SC-KS2-C025)

Type: Knowledge | Teaching weight: 3/6

Understanding that most forces require direct contact between objects (e.g., pushing, pulling, friction) but some forces, notably magnetic forces and gravity, can act at a distance without direct contact.

Teaching guidance: Explore contact forces through practical activities: pushing and pulling objects, observing friction between surfaces, and feeling the resistance of water when moving objects through it. Introduce non-contact forces using magnets (attraction and repulsion without touching) and dropping objects (gravity pulls without touching). Create a two-column sorting activity: 'forces that need touching' versus 'forces that act at a distance'. Use force arrows to represent the direction of forces on simple diagrams. Discuss everyday examples of both types. Key vocabulary: force, push, pull, contact, non-contact, friction, gravity, magnetic, attract, repel, distance, surface, direction, strength, interaction Common misconceptions: Children commonly think a force is needed to keep an object moving, rather than understanding that forces are needed to start, stop or change movement (a precursor to Newton's first law). Some pupils believe gravity only acts on heavy objects or only works at large distances. Children may think that magnetic force requires contact because they usually see magnets touching metal objects — they need to explore magnetic attraction through materials and at a distance.

Differentiation

Model response (Entry): Pushing a door open is a push force. Pulling a drawer out is a pull force.

Model response (Developing): Contact forces (need touching): friction (surfaces rubbing), pushing a trolley (hand touches trolley). Non-contact forces (act at a distance): gravity (pulls objects down without touching), magnet (attracts paper clip without touching it).

Model response (Expected): A non-contact force acts between objects without them touching. Gravity pulls all objects toward the Earth — when you drop a ball, gravity pulls it down even though nothing visible is pushing it. Magnetic force can attract or repel — a magnet attracts an iron paper clip across a gap, pulling it through the air without touching. Both forces get weaker with distance. Contact forces like friction and air resistance require surfaces or objects to be in direct contact.

Model response (Greater Depth): Yes, two forces are acting on the book even though it is not moving. Gravity pulls the book downward toward the Earth. The table pushes the book upward with an equal force (called the normal reaction force). These forces are balanced — they are equal in size but opposite in direction, so the book stays still. If the forces were unbalanced (for example, if you pushed down on the book), the book would move. Objects can have forces acting on them and still be stationary — this happens when the forces are balanced. This is an important idea that leads to Newton's First Law.

Secondary concept: Friction and Movement on Surfaces (SC-KS2-C027)

Type: Knowledge | Teaching weight: 3/6

Understanding that the surface of an object affects how it moves — rough surfaces produce more friction and slow objects down more than smooth surfaces. Friction is a contact force.

Differentiation

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Thinking lens: Patterns (primary)

Key question: What patterns can I notice here, and what do they allow me to predict? Why this lens fits: Data from repeated investigations reveals patterns that allow pupils to generalise their findings beyond the specific test conditions. Question stems for KS2:

What pattern can you see?

Does this always happen, or can you find an exception?

What rule connects these examples?

What would you predict for the next one? Why?

Secondary lens: Cause and Effect — Fair testing and investigations are designed to isolate variables and establish causal relationships — the cognitive demand is reasoning from controlled evidence to causal claims.

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Session structure: Fair Test

Fair Test

The classic scientific enquiry: formulating a testable question, making a prediction based on scientific understanding, designing a method that controls variables, collecting and recording data systematically, analysing results, and drawing a conclusion linked back to the original hypothesis.

question → hypothesis → method → data_collection → analysis → conclusion Assessment: Structured scientific report including question, hypothesis with reasoning, method with variables identified, results table/graph, and conclusion evaluating whether results support the hypothesis. Teacher note: Use the FAIR TEST template: frame a testable question and guide pupils to identify the variable they will change, measure, and keep the same. Support them in making a prediction with a scientific reason. Collect measurements using appropriate equipment and record results in a table. Guide pupils to describe patterns in their results and say whether their prediction was supported. KS2 question stems:

What is our testable question?

What will you change, measure, and keep the same?

What pattern can you see in your results?

Does the evidence support your prediction? How do you know?

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Variables

Independent: surface type (carpet, wood, sandpaper, tile, fabric) Dependent: distance travelled by toy car (cm) Controlled: ramp angle, car mass, release point, same car

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Equipment and safety

Equipment:

ramp

toy car

metre stick

surface samples (carpet, wood, sandpaper, tile, fabric)

masking tape

Safety notes: Low risk. Ensure ramp is stable and surfaces are secured flat. Keep floor area clear to prevent tripping over ramp equipment. (Hazard level: low)

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Expected outcome

Rougher surfaces produce more friction, so the car travels a shorter distance. Smooth surfaces produce less friction. Friction is a contact force that opposes motion between surfaces.

Recording format: results table, bar chart, written conclusion

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Enquiry type

Fair Test

A controlled investigation where one variable is deliberately changed while all others are kept the same, to determine whether the changed variable has an effect on a measured outcome. The gold-standard enquiry type for causal questions in science.

KS2 guidance: At KS2, fair tests should involve tangible, observable variables. Pupils identify what they will change, measure, and keep the same. Predictions use 'I think... because...' stems. Data is recorded in tables and presented as bar charts or line graphs. Conclusions state whether the prediction was supported and give a simple causal explanation. Question stems:

How does [independent variable] affect [dependent variable]?

Does changing [variable] make a difference to [outcome]?

What is the relationship between [variable A] and [variable B]?

Teacher scaffold:

What will you change? (independent variable)

What will you measure or observe? (dependent variable)

What will you keep the same? (controlled variables)

What do you predict will happen? Why?

Was your prediction correct? What does the evidence show?

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Known misconceptions

Friction is always unhelpful

What pupils may say: Friction is always a bad thing that slows us down. Correct explanation: Friction is essential for many everyday actions. Without friction, you could not walk (your feet would slip), hold a pen, grip a steering wheel, or brake a car. Friction is only unhelpful when it wastes energy or causes wear in machines. Whether friction is helpful or unhelpful depends on the context. Diagnostic questions:

Can you name three situations where friction is helpful?

What would happen if there was no friction between your shoes and the floor?

Is friction always something we want to reduce?

Smooth surfaces have no friction

What pupils may say: Smooth surfaces have no friction. Correct explanation: All surfaces have some friction when they are in contact. Smoother surfaces have less friction than rougher surfaces, but friction is never zero. Even ice has friction. If there were truly no friction, you could not walk, hold objects, or stop a moving car. Friction is reduced on smooth surfaces but always present. Diagnostic questions:

If there were truly no friction on an ice rink, would you be able to stand up?

Does a smooth surface have zero friction or just less friction than a rough one?

What would the world be like with absolutely no friction?

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Why this study matters

This is the most accessible fair test in the KS2 curriculum because pupils can see and feel friction, the variables are tangible, and the measurement (distance) is straightforward. The investigation builds all the core fair testing skills: identifying variables, measuring accurately, recording in a table, presenting as a bar chart, and writing a causal conclusion.

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Pitfalls to avoid

Inconsistent release of the car on the ramp leads to unreliable data — model a consistent release technique before starting

Pupils confuse friction with gravity or air resistance — clarify friction requires contact between two surfaces

Pupils may think smooth surfaces have 'no friction' rather than 'less friction'

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Cross-curricular opportunities

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Working scientifically skills (KS2)

These disciplinary skills should be woven through teaching, not taught in isolation:

Identifying and classifying — Sorting and grouping objects, organisms or materials according to their observable characteristics, recognising that things can be classified in more than one way depending on which features are selected.

Making and recording observations with evaluation of method — Conducting observations and measurements using a range of apparatus and methods appropriate to the investigation, and critically evaluating the reliability of those methods with reasoned suggestions for improvement.

Communicating findings — Presenting the outcomes of scientific enquiry in oral and written forms — including explanations, displays and presentations — using appropriate scientific language and representations to convey methods, results and conclusions clearly to others.

Asking relevant questions and selecting enquiry types — Formulating focused scientific questions and selecting the most appropriate enquiry method to answer them, choosing between observing over time, pattern seeking, classifying, comparative tests, fair tests, or secondary research as the situation demands.

Evaluating evidence and understanding scientific knowledge development — Critically evaluating data for random and systematic error, and understanding how scientific methods and theories evolve as new evidence emerges — including the roles of publication, peer review and replication in establishing trustworthy scientific knowledge.

Drawing conclusions and evaluating evidence — Using collected data to draw conclusions, identify causal relationships, make and test predictions, and assess the degree of trust that can be placed in results, recognising when evidence supports or refutes a scientific idea.

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Vocabulary word mat

Prior knowledge (retrieval plan)

Pupils should already know the following from earlier units:

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Scaffolding and inclusion (Y5)

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Knowledge organiser

Key terms:

friction

force

contact force

surface

fair test

variable

conclusion

Core facts (expected standard):

Contact and Non-Contact Forces: Explaining the difference between contact and non-contact forces with multiple examples, and understanding that forces can be measured using a force meter (Newtons).

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Graph context

Node type: ScienceEnquiry | Study ID: SE-KS2-001 Concept IDs:

SC-KS2-C025: Contact and Non-Contact Forces (primary)

SC-KS2-C027: Friction and Movement on Surfaces

Cypher query:

``cypher

MATCH (ts:ScienceEnquiry {enquiry_id: 'SE-KS2-001'})

-[:DELIVERS_VIA]->(c:Concept)

-[:HAS_DIFFICULTY_LEVEL]->(dl)

RETURN c.name, dl.label, dl.description

``

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Generated from the UK Curriculum Knowledge Graph — zero LLM generation.