Testing Slide Friction

Overview

Lesson 7 of 15 in Playground Physics and Design. Students investigate how surface material affects friction and motion by repeating ramp tests, recording time or distance, and using evidence to recommend a playground slide surface.

Learning intentions

• WALT explain that friction can slow moving objects.
• WALT carry out a fair test by changing one factor and keeping others the same.
• WALT measure, record and compare motion using time or travel distance.
• WALT use evidence to make a design recommendation and identify a limitation.

Success criteria

• I can describe how a surface affects how far or how quickly an object moves.
• I can help keep a ramp test fair and repeat it consistently.
• I can record results clearly and identify a pattern.
• I can recommend a slide material using evidence and explain one limitation of the test.

Curriculum links

• Physical world: exploring forces, including friction, and how forces affect movement.
• Science capabilities: observing, measuring, recording, interpreting data, and using evidence to explain ideas.
• Nature of science: carrying out a simple fair test and recognising that scientific tests have limitations.
• Technology and design: using test results to inform a playground design decision and considering safety and suitability.

Lesson structure (45 minutes)

1. 0–5 minutes – Hook and prediction Open with the friction hook and prediction slide. Show a smooth plastic surface, a steel-like surface and a rough material, then ask: “Which slide would let the same object move fastest, and which would stop it soonest?” Students make a quick prediction with a partner and explain their thinking.

2. 5–10 minutes – Build shared understanding Use the friction explanation slides to introduce friction as a force that resists movement when two surfaces rub. Demonstrate sliding the same object over two materials. Discuss why a slide must be smooth enough to allow movement but not so slippery that it becomes unsafe.

3. 10–15 minutes – Model a fair test Refer to the fair-test instructions and demonstrate one ramp test. Keep the ramp height, object, starting point and distance measured the same; change only the surface. Explain that the object must be released without pushing. Model timing from release to the finish line, or measuring how far it travels in a set time.

Organise 25 students into five groups of five: equipment manager, releaser, timer, recorder and observer. Establish safety rules: test objects only, keep hands clear, collect materials carefully, and do not slide people or run equipment on the floor.

4. 15–30 minutes – Repeated ramp tests Distribute the friction investigation recording sheet to each group. Groups test smooth plastic, a steel-like surface and at least one other available material. Complete at least three trials for each surface, recording time or travel distance and noting anything that made the test less fair.

Encourage groups to reset the ramp in exactly the same position before every trial. Pause halfway for a quick check: “Are we changing only the surface?” Support groups to repeat any result that seems unusual rather than immediately removing it.

5. 30–37 minutes – Compare and interpret results Return to the results comparison prompts. Groups compare their repeated results and decide which surface produced the fastest movement or greatest distance. They circle or describe the pattern on their worksheet and discuss whether the evidence supports their original prediction.

6. 37–43 minutes – Design recommendation Groups complete the recommendation section on the friction investigation recording sheet: “For our playground slide, we recommend…” They must name a material, use one or two results as evidence, and explain one limitation, such as small sample size, inconsistent release, timing errors, different material thicknesses or not testing a real slide.

Invite three or four groups to share. Ask: “Would the fastest surface automatically be the best slide? What else would a playground designer need to consider?” Prompt ideas such as safety, comfort, durability, heat and cost.

7. 43–45 minutes – Plenary and check for understanding Use the final reflection slide. Students tell a partner: “Friction affected our object by…” and “One way to improve our test would be…” Collect worksheets for assessment.

Resources

• the friction and investigation slide deck
• the friction investigation recording sheet
• Five low-angle ramps, such as books and sturdy boards
• Identical small objects, such as toy cars or blocks
• Smooth plastic, steel-like material and two contrasting materials
• Metre rulers or measuring tapes
• Stopwatches, tablets or classroom timers
• Masking tape for start and finish lines
• Pencils and clipboards
• Safety reminder displayed before testing

Assessment

• Observe groups for fair-test practice: consistent release, controlled variables, safe equipment use and repeated trials.
• Check worksheets for labelled materials, recorded results, comparisons and a recommendation supported by evidence.
• Listen to explanations for accurate use of friction, movement, evidence and limitation. Note students who need further support with measuring or interpreting results.

Differentiation

• Provide a pre-labelled worksheet table, picture instructions and an adult or peer model for students needing support. Allow students to record distance rather than time if timing is difficult.
• Pair students strategically and assign a clear role to each group member. Use sentence frames: “The ___ surface made the object move ___ because…” and “Our evidence is…”
• For EAL learners, demonstrate surface, friction, force, trial, evidence and fair test with real materials and gestures; accept oral explanations before written responses.
• Extend confident students by comparing the range of repeated results, identifying the most reliable surface, or proposing a follow-up test that changes only one additional factor, such as ramp angle.