Science // Forces & Motion

Friction & Surfaces

Compare how things move on different surfaces, noticing that some surfaces create more friction than others

Ages
7 to 8
Type
Concept
Builds on
2 topics
Leads to
3 topics
Standards
1 code

Quick check

Can the learner explain why a toy car rolls further on a smooth wooden floor than on carpet?

Ask this to see whether the topic is secure.

Topic // Mastery

What mastery looks like

What a learner can do once this topic is secure.
  • Observe and compare how the same object moves on at least three different surfaces
  • Describe that rough surfaces slow objects down more than smooth surfaces
  • Use the word 'friction' to explain why movement differs on different surfaces

Topic // Map

Where this fits

What to learn first and what this topic opens up, with the reason for each link. Required links come first.
  • RequiredMust come first
  • HelpfulHelps, but not essential

Before this

2 topics
  • Pushes & PullsRequired

    Forces & Motion // Ages 5 to 6

    Must understand forces change motion before comparing movement on different surfaces

  • Forces VocabularyRequired

    Forces & Motion // Ages 5 to 8

    Comparing how things move on different surfaces requires friction vocabulary

You are here

Friction & Surfaces

Ages 7 to 8 // Concept

Leads to

3 topics
  • Contact & Non-Contact ForcesRequired

    Forces & Motion // Ages 7 to 8

    Must experience contact forces like friction before distinguishing contact vs non-contact forces

  • Balanced & Unbalanced ForcesRequired

    Forces & Motion // Ages 8 to 9

    Must understand friction affects motion before investigating balanced/unbalanced forces

  • Air Resistance & FrictionRequired

    Forces & Motion // Ages 9 to 10

    Must know friction from surface comparisons before learning about air/water resistance as similar forces

Topic // Research-informed

Teaching notes

From the Marble Skill Taxonomy. These notes have not been validated in classrooms, so treat them as a starting point for your own judgement.

The approach

For 7–8 year olds, teach friction as a FORCE between two surfaces that opposes sliding motion, not merely a property of 'rough things'. Central activity: send the SAME object across several surfaces (ice, polished wood, carpet, sandpaper) as a fair test, measure distance travelled, and represent the invisible friction with a force arrow pointing against the motion. Use the Institute of Physics grip/slip framing, connect slip to warming, and confront the 'push runs out' impetus idea plus the 'shiny = slippery' confusion. For grip (static friction), be clear it balances an applied push or a slope's pull — a still object with nothing pushing it has no horizontal friction. Includes consolidation sorting/ordering, an annotated real-world reference, and a two-tier diagnostic.

Common misconceptions

  • Friction is a phenomenon or a 'thing', not named/treated as a force (IOP).
  • Friction only acts when things move (slip) — or the mirror error, only when things are still (grip); both are partial views (IOP).
  • Friction is always bad/undesirable, ignoring that grip is what lets us walk and brake.
  • Things stop because the push/force 'runs out', rather than because friction pushes back (impetus link).
  • Confusing smoothness with shininess ('shiny = slippery'); and comparing rolling resistance with sliding as if they were the same.
  • Reasoning backwards from effect to cause — 'it took a long time to stop, so the friction must have been small' (IOP tripwire).

Useful representations

  • Multi-surface runway/ramp with one object and a distance scale
  • Force arrow opposing motion ('forces spectacles' — making the invisible friction visible)
  • Grip vs slip labelling of frictional forces (IOP)
  • Data table: surface ↔ distance travelled
  • Warming demonstration (rubbing hands / surfaces) to feel slip dissipating energy

Teaching practices

  • Hands-on comparison: send the same object across at least three surfaces and measure distance travelled, keeping everything else the same (links to fair testing / pattern-seeking).
  • Name friction as a FORCE that opposes motion and represent it with an arrow pointing against the movement ('forces spectacles'), since friction is invisible (IOP).
  • Use the IOP grip/slip framing and a warming demonstration (rub hands together; feel a surface warm under sliding) to make the invisible force tangible — slip warms things, grip does not.
  • Foreground friction as the REASON things slow and stop, directly countering the 'force runs out' impetus idea.
  • Clean the variable: compare smoothness/roughness, and beware confounds — 'shiny' is not the same as 'low friction', and rolling must not be compared with sliding.
  • Discuss friction as both helpful (grip lets us walk, brakes work) and unhelpful (slows a sledge) so it isn't cast as simply 'bad'.

Activities to try

  1. 1

    Same object, different surfaces: a fair-test friction runway

    Why it works: Changing only the surface changes how far the same pushed object travels before it slows to a stop: rougher surfaces produce more friction and stop the object sooner. This is a fair test — keep the object and the push the same, change only the surface.

    1. Set up a flat runway (physical track, or a screen simulation of one) and choose one object (e.g. a puck or wooden block) that you will NOT change between runs.
    2. Before each run, predict how far the object will travel and mark your predicted stopping point.
    3. Give the object the same push each time (e.g. release it from the same point on a small launch ramp or pull back a rubber band by the same amount, since hand flicks vary), send it across at least three different surfaces in turn (e.g. ice/very smooth, polished wood, carpet, sandpaper), repeat each run a few times, and keep everything else the same so only the surface changes.
    4. Measure and record how far it travelled on each surface in a data table (surface ↔ distance), and build up a simple bar chart so the pattern becomes visible.
    5. Order the surfaces from 'object travels furthest' to 'stops soonest' and describe the pattern in your own words.
  2. 2

    Forces spectacles: drawing the invisible friction arrow

    Why it works: Friction is a force acting between two surfaces in contact, opposing their sliding. Though invisible, it can be represented by an arrow pointing against the motion; it is larger on rougher surfaces, which is why the object slows and stops sooner.

    1. After a run, draw a force arrow on the moving object pointing BACKWARDS, against the direction it is sliding — this represents the friction slowing it.
    2. Compare runs: draw a short arrow for a smooth surface and a longer arrow for a rough surface, matching 'more friction = longer arrow'.
    3. Say out loud which way friction pushes and why the object slows: friction is a force from the surfaces acting against the sliding motion.
    4. Optionally, in a screen simulation, toggle a 'forces spectacles' overlay that shows the opposing arrow growing longer on rougher surfaces, and watch a warming meter glow on the rough, sliding runs.
  3. 3

    Grip and slip, and the warming you can feel

    Why it works: Friction has two faces. Grip (static friction) can act on a still object WHEN something pushes it or it rests on a slope — it balances that push up to the point the object starts to slide. Slip (sliding friction) slows an object already sliding and warms the surfaces. Friction is both helpful and unhelpful depending on the situation.

    1. Rub your hands together quickly and feel them warm up — notice that sliding (slip) between surfaces produces heat.
    2. Discuss grip: push gently on a shoe (or block) resting on a path and notice it does NOT slide until you push hard — static (grip) friction is balancing your push before the object moves.
    3. Sort example situations into grip (prevents sliding: walking without slipping, standing on a slope without sliding, a parked object on a slope held in place, brakes holding) and slip (slows an existing slide: a sledge stopping, a skidding object).
    4. Discuss friction as both helpful (grip lets us walk and lets brakes work) and unhelpful (slows a sledge) so friction is not labelled simply 'bad'.

Topic // Standards

Curriculum standards

Codes for the curriculum statements this topic maps to. Each publisher owns its standard text.
The national curriculum in England: Key stages 1 and 2 framework document
Y3.Sci.FM.1

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