Balance Leverage Proportions

Overview

This lesson applies balance and leverage concepts to a cardboard “weapon” model, then uses proportions to calculate missing Red Orb shop values. Students also practise engineering vocabulary spelling and compose a short mechanical “song” that explains the science ideas.

Learning intentions

• Students will build a cardboard balance scale that demonstrates equal/unequal forces using a clear design.
• Students will solve missing-value proportion problems using visual supports (bar/ratio model).
• Students will identify and correctly use key engineering vocabulary in short written/sung phrases.
• Students will explain balance and leverage using an oral or multimodal mechanical song.

Success criteria

• I can create a balance scale where moving a weight changes what is heavier/lightest and I can explain why.
• I can calculate a missing Red Orb value in a proportion problem and show my working with a visual model.
• I can spell at least 5 engineering terms correctly (or confidently match them to correct labels if using support).
• I can deliver a 20–40 second mechanical song that includes balance/leverage/proportion ideas clearly.

Curriculum links

• English (Literature): create and edit literary texts adapting ideas from experiences; use devices to shape meaning and setting.
• English (Literacy): use comprehension strategies to build literal and inferred meaning and connect information using questions and monitoring.
• English (Language): identify and use vivid, emotive vocabulary and imagery; select precise language for effect.
• English (Language): improve cohesion by intentional repetition and word associations across sentences or a chorus.
• English (Language): choose suitable language level for an audience (spoken “mission” explanation vs notes).

Lesson structure (60 minutes)

1. 0–5 min · Mission hook (high-dopamine). Teacher shows two quick “balance” demos (one side heavier; one side equal) using a cardboard scale and a ruler fulcrum. Students turn-and-talk: “What changed? What stayed the same?” (sentence starter card provided).

2. 5–12 min · Direct teach: balance, leverage, proportion (visual first). Teacher explains: balance = equal effect; leverage = distance from pivot changes outcome; proportion = same relationship between sets, shown by a bar model. Students label a simple diagram: pivot, effort arm, load arm, heavier side, equal side (word bank + colour coding).

3. 12–28 min · Build & test: cardboard balance scale. Teacher circulates with “coach prompts” (Why did it tip? What if we move the weight closer?). Students build a scale from common materials (paperboard/cardboard, skewer or pencil fulcrum, string/holder, paperclips/coins, tape) and complete a 3-row testing log:

• Row 1: Equal (record positions)
• Row 2: Unequal (record what moved)
• Row 3: “Switch it back” (describe how they achieved balance again)

4. 28–40 min · Proportion problems: Red Orb pricing (with visuals). Teacher models one worked example using a bar/ratio table (e.g., “If 1 Orb piece costs 4 Red Orbs, how much for 6 pieces?” shown as linked bars with matching units). Students solve 2 missing-value problems on a “Ratio Map” worksheet: each student chooses one support option:

• Option A: bar model template
• Option B: ratio table template
• Option C: number line with “same scale” marks Students must show a visual step and a final answer.

5. 40–50 min · Engineering vocabulary spelling sprint (low reading friction). Teacher provides a “label-to-word” matching sheet and a mini word bank: pivot, leverage, balance, weight, force, ratio, proportion, equal, closer, farther. Students complete one of:

• Write 5 words from dictation (teacher read-aloud)
• Or copy labels onto their diagram and then add missing vowels (dyslexia-friendly scaffold)

6. 50–58 min · Mechanical song compose & perform. Teacher demonstrates a chorus structure using repetition and word associations: “Balance on the pivot, leverage makes it shift…” Students compose a 20–40 second song explaining: how distance from pivot changes balance, and one proportion idea (“same relationship” in their own words). They perform to a partner; audio-recording option available.

7. 58–60 min · Exit ticket (quick check). Students answer one prompt: “In one sentence, why did the scale tip?” plus one missing-value final answer (tick box + short response).

Resources

• Cardboard/paperboard, ruler, pencil/skewer, tape, string
• Coins/paperclips or bottle caps as weights
• “Balance scale” diagram handout (pivot + arms)
• Ratio Map worksheet (bar model + ratio table options)
• Engineering word bank (print + coloured labels)
• Testing log sheet with 3 rows
• Sentence starter cards and read-aloud teacher prompts
• Optional: phone/tablet for voice recording, audio playback
• Dyslexia-friendly supports: large font, ample spacing, high-contrast colours

Assessment

• Formative during build/testing: teacher checks explanations using a 3-point checklist (identifies pivot; predicts tip; revises after test).
• Formative during proportion: verify correct visual model match to calculation method and final missing value.
• Exit ticket: one-sentence cause explanation + final proportion answer.
• Checklist for song includes: uses at least 2 science terms and one proportion phrase; clear understandable explanation.

Differentiation

• Provide choice of outputs each task (testing log + draw, or test log + voice notes; proportion bar model or ratio table; song recorded or performed).
• Use reduced writing: allow “label-only” responses and sentence starters (“The scale tipped because…” “Proportion means…”).
• Neurodivergent support: short timed bursts, movement breaks between tasks, predictable routine with visual timers, and “coach prompts” instead of lengthy corrections.
• Dyslexia support: read-aloud prompts, word banks, colour-coded units, and cloze sentence frames (e.g., “Leverage changes when we move the weight ___ the pivot.”).