Friction and Motion

Overview

In this lesson, students learn how friction can either slow motion or help objects move safely and effectively. They conduct short investigations to compare how different surfaces affect sliding and stopping.

Learning intentions

• Students will define friction and describe how it affects motion.
• Students will predict how changing a surface will change the distance/time of a sliding object.
• Students will collect and record observations using simple measurements.
• Students will explain results using evidence from their experiments.

Success criteria

• I can explain friction as a force that opposes motion between surfaces.
• I can describe at least two effects of friction on moving objects.
• I can use data (or well-organized observations) to support an explanation of what my experiment showed.
• I can identify variables and describe how I kept a fair test.

Curriculum links

• Forces and motion: how forces affect changes in motion, including friction.
• Scientific investigation skills: forming a hypothesis, identifying variables, and using evidence to draw conclusions.
• Data and evidence: using measurements/observations to support claims.
• Communication: using scientific language to explain findings clearly.

Lesson structure (45 minutes)

1. 0–5 min | Hook + prompt Teacher demonstrates two short scenarios: a book slides on a smooth surface and then on carpet. Students quickly discuss: “Why did it move differently?” Record key ideas (friction, surface, stopping).

2. 5–12 min | Mini-lesson: friction in motion Teacher explains friction as a force between surfaces that opposes sliding, and links it to everyday examples (walking, brakes, sledding, bicycle tires). Students turn-and-talk to connect at least one example to “friction slows motion” or “friction helps traction.”

3. 12–18 min | Planning the investigation In groups of 3–4, students receive a basic lab sheet and materials (block, track or board, different surface strips like cardboard, sandpaper, felt; meter sticks; stopwatch if available). Teacher models identifying:

• Independent variable: surface type
• Dependent variable: distance slid (and/or time)
• Controlled variables: starting position, push strength/release method, track angle, block mass Students write a prediction: “If the surface is ___, then the block will slide ___ because friction will ___.”

4. 18–30 min | Experiment 1: surface comparisons Students run trials on two surfaces, aiming for repeated trials (at least 2 per surface if time allows). They record measurements (distance slid from release point) and note observations (sound, scraping, speed changes). Teacher circulates to check fairness of tests and supports accurate measuring.

5. 30–37 min | Whole-class evidence check Groups share one data point and one observation. Teacher prompts with sentence starters:

• “Our results show that…”
• “This likely happened because…”
• “Friction changed because…” If there are differences between groups, teacher highlights that friction varies with surface texture and contact.

6. 37–43 min | Explanation writing (CER) Students write a brief “Claim–Evidence–Reasoning” paragraph:

• Claim: which surface caused more/less sliding
• Evidence: measured distances or recorded observations
• Reasoning: friction opposes motion and depends on contact between surfaces Provide a word bank (friction, surface, motion, opposes, slows, traction, roughness, smoothness).

7. 43–45 min | Exit ticket Students answer two questions:

• “What is friction and what does it do to moving objects?”
• “How did changing the surface affect motion in your investigation?”

Resources

• Small block or puck, track/board (or taped “start” and “finish” marks)
• Variety of surface materials: smooth cardboard, rough sandpaper, felt, fabric, rubbery mat (as available)
• Meter stick or measuring tape
• Stopwatch (optional if time/teacher equipment allows)
• Lab sheets with variable table and data table
• Marker tape or painter’s tape for start lines
• Student science notebooks or lined paper
• Word bank for ESL supports
• Safety guidance (keep fingers clear of moving objects; manage sandpaper carefully)

Assessment

• Formative: teacher checks group investigations for fair testing and correct variable identification.
• Formative: review lab-recorded data for accuracy and clarity (measurements/observations).
• Summative (small): exit ticket responses assessing friction definition, effects on motion, and evidence-based explanation.

Differentiation

• Support (ESL/Beginning learners): sentence frames for predictions and CER; word bank; model using a “friction → slows/speeds up” diagram; allow oral responses recorded by teacher or peer.
• Support (SEN): provide a partially filled data table; reduce measurement complexity (use distance only, not time); provide checklists for “controlled variables” and “fair test.”
• Extension (advanced learners): ask students to calculate average distance over trials and discuss sources of error (inconsistent push/release, surface debris, track level).
• EAL strategies: pair proficient with developing peers; pre-teach essential terms (friction, surface, sliding, measurement) using real objects; encourage students to explain reasoning using home language ideas before producing English/structured sentences.