thermoplastics and thermosets
4 detailed 50-minute lessons with teaching scripts, worked examples, parent guides, and assessment criteria.
Lesson Overview
Total Lessons: 4
Tier: Foundation and Higher
Duration: 50 minutes per lesson (200 minutes total)
Exam Boards: AQA, Edexcel, OCR, Eduqas, CCEA
Tier: Foundation and Higher
Duration: 50 minutes per lesson (200 minutes total)
Exam Boards: AQA, Edexcel, OCR, Eduqas, CCEA
Learning Objectives
- Explain the key ideas of thermoplastics and thermosets
- Apply thermoplastics and thermosets to exam-style questions
- Develop independent study skills
- Build cross-topic connections
Prerequisites
- Read the revision notes for thermoplastics and thermosets first (GCSE Revise summary)
- Key vocab to pre-teach: D&T Exam Tips
- Basic skills: reading the summary notes and answering the practice questions there
Materials & Equipment
- Exercise book, coloured pens
- Ruler
- Printed revision notes (link below)
- Internet for videos (see Resources)
Lesson 1: Introduction: thermoplastics and thermosets
Duration: 50 minutes
Starter Activity (5 minutes)
Quick Recall
Write down everything you already know about thermoplastics and thermosets. Then check against the key terms: D&T Exam Tips. Use a mini-whiteboard or paper.
Main Content (35 minutes)
Parent/Teacher Guide:
Before lesson: Read the script below. Pre-teach key vocab: D&T Exam Tips.
If stuck: Re-read the revision notes (link above), then break the content into smaller steps.
Extension: See the Stretch & Challenge ideas in Lesson 4.
Before lesson: Read the script below. Pre-teach key vocab: D&T Exam Tips.
If stuck: Re-read the revision notes (link above), then break the content into smaller steps.
Extension: See the Stretch & Challenge ideas in Lesson 4.
Teaching Script (35 mins):
Mins 0-5 - Hook: "Today: thermoplastics and thermosets. By the end you will be able to answer exam questions on it unaided. It connects to the rest of Design and Technology because the ideas here recur across the spec."
Mins 5-20 - Direct Instruction: Work through the core ideas below one at a time; after each, ask your student to explain it back in their own words.
Mins 20-30 - Guided Practice: Model the worked example together, then let your student attempt the first practice question with guidance.
Mins 30-35 - Independent Practice: 2-3 practice questions from Lesson 3 below, with immediate feedback.
Mins 0-5 - Hook: "Today: thermoplastics and thermosets. By the end you will be able to answer exam questions on it unaided. It connects to the rest of Design and Technology because the ideas here recur across the spec."
Mins 5-20 - Direct Instruction: Work through the core ideas below one at a time; after each, ask your student to explain it back in their own words.
Mins 20-30 - Guided Practice: Model the worked example together, then let your student attempt the first practice question with guidance.
Mins 30-35 - Independent Practice: 2-3 practice questions from Lesson 3 below, with immediate feedback.
First Look
Start with the revision notes summary, then attempt: Explain the structural difference between thermoplastics and thermosets and how this affects their recyclability.
Plenary (5 minutes)
Check Out
Your student states one thing they learned and one question they still have about thermoplastics and thermosets.
Lesson 2: Core Concepts: thermoplastics and thermosets
Duration: 50 minutes
Starter Activity (5 minutes)
Review Previous Lesson
Quick recap: write 3 key points from Lesson 1 on thermoplastics and thermosets. Check them against the notes below.
Main Content (35 minutes)
Key Fact: Thermoplastics: linear polymer chains - soften when heated, solidify when cooled, can be remelted repeatedly. ABS (lego), acrylic (signs), PP (living hinges), HDPE (milk bottles).
Key Fact: Thermosets: cross-linked polymer chains - set permanently once cured, cannot be remelted, char when reheated. Epoxy resin (adhesives), melamine (worktops), polyester resin (fibreglass).
Key Fact: Polypropylene (PP): excellent fatigue resistance (living hinges on bottle caps), chemical resistant, lightweight, microwave-safe.
Key Fact: Polycarbonate: virtually unbreakable, transparent, high impact resistance - safety glasses, riot shields, CDs.
Key Fact: Recycling: thermoplastics are recyclable (melt and reform); thermosets cannot be melted down - ground into filler or burned for energy.
D&T Exam Tips: For polymer questions: 1) Classify as thermoplastic or thermoset, 2) Explain the chain structure, 3) State relevant properties, 4) Link to specific application, 5) Comment on recyclability if relevant.
| Term | Meaning | Example |
|---|---|---|
| Acrylic (PMMA) | Thermoplastic | Transparent, polished edges |
| ABS | Thermoplastic | Tough, impact-resistant |
| Polypropylene | Thermoplastic | Fatigue-resistant, living hinge |
| HDPE | Thermoplastic | Chemical-resistant, stiff |
| Epoxy resin | Thermoset | Strong adhesive, heat-resistant |
| Melamine | Thermoset | Hard, heat-resistant surface |
Practice (10 minutes)
Q: Explain the structural difference between thermoplastics and thermosets and how this affects their recyclability.
Answer: Thermoplastics have linear chains with weak intermolecular forces - heat overcomes these, chains slide apart (melt), cool and reform. Repeatable = recyclable. Thermosets have cross-links (covalent bonds) - once cured, permanent, cannot be undone by heating, so they char rather than melt.
Plenary (5 minutes)
Explain Back
Your student teaches the key points back to you without looking. Fill any gaps immediately.
Lesson 3: Application: thermoplastics and thermosets
Duration: 50 minutes
Starter Activity (5 minutes)
Quick Recall
Recall the key terms: D&T Exam Tips. Define each in one sentence.
Main Content (35 minutes)
Parent/Teacher Guide: Let your student attempt each question alone first, then compare with the model answer. Award method marks for correct working even if the final answer is wrong.
Q1: Explain the structural difference between thermoplastics and thermosets and how this affects their recyclability.
Answer: Thermoplastics have linear chains with weak intermolecular forces - heat overcomes these, chains slide apart (melt), cool and reform. Repeatable = recyclable. Thermosets have cross-links (covalent bonds) - once cured, permanent, cannot be undone by heating, so they char rather than melt.
Q2: A designer needs a transparent, impact-resistant material for a safety goggles lens. Justify the choice of polycarbonate over acrylic.
Answer: Polycarbonate: extremely high impact resistance (250x stronger than glass, 30x stronger than acrylic), transparent. Acrylic: good transparency, but brittle - shatters on high impact. For safety goggles, polycarbonate is essential because it deforms rather than shatters.
Q3: Explain why a living hinge on a shampoo bottle cap must be made from polypropylene and not from acrylic.
Answer: A living hinge is an extremely thin section that flexes repeatedly. Polypropylene has exceptional fatigue resistance - semi-crystalline structure allows millions of flex cycles. Acrylic is amorphous and brittle - would crack after very few flexes.
Plenary (5 minutes)
Error Review
Review any questions answered incorrectly. Identify whether the error was knowledge, method, or reading the question.
Lesson 4: Exam Practice: thermoplastics and thermosets
Duration: 50 minutes
Starter Activity (5 minutes)
Command Words
Review what these command words require: state (one point), describe (say what happens), explain (say why), compare (both sides), evaluate (judgement).
Main Content (35 minutes)
Extended Answer
Extended question: Full-Mark Response A company is designing a reusable, recyclable water bottle. Evaluate the suitability of HDPE, PET and polycarbonate, recommending the most appropriate material. <div class="
A grade 9 response will: evaluate HDPE (opaque/translucent, widely recycled code 2, BPA-free, inexpensive, tough); PET (clear, widely recycled code 1, good strength); polycarbonate (very clear, extremely tough, but BPA concerns, recycled less widely code 7). Conclude: PET for clear bottles, HDPE for sport bottles, polycarbonate less suitable due to BPA concerns.
Exam Tips: Always explain the STRUCTURAL reason for thermoplastic vs thermoset behaviour (chain structure, cross-links) | Know at least two applications for each named polymer | Link polymer name to abbreviation: PP = polypropylene, PC = polycarbonate, PMMA = acrylic
Common Errors: Watch Out! Students often make mistakes here. Wrong: Thermosets are stronger than thermoplastics because they have cross-links, so they are always the better choice for strong products. Correct: Cross-links make thermosets rigid and heat-resistant but also brittle - they cannot absorb impact energy well. Many thermoplastics are extremely tough (polycarbonate, nylon) and stronger in practice for impact applications. Thermosets excel where heat resistance and dimensional stability are priorities.
Stretch & Challenge (Grade 8-9):
- Synoptic links: explain how thermoplastics and thermosets connects to another Design and Technology topic you have studied
- Real-world: research one real-world use or example of thermoplastics and thermosets
- Critical: "What are the limitations of the models used in thermoplastics and thermosets?"
Plenary (5 minutes)
Assessment Criteria
- Got it: Confident explanation + correct worked examples
- Getting there: Main points OK, needs support with detail
- Not yet: Confused on key concepts - re-run Lesson 2
Homework & Consolidation
- Consolidation: Re-answer any Lesson 3 practice questions answered incorrectly (20 mins)
- Retrieval: Write flashcards for the key terms: D&T Exam Tips (10 mins)
- Exam practice: One past-paper question on thermoplastics and thermosets from the board websites (15 mins)
- Extension: Explain thermoplastics and thermosets to someone else in your own words (10 mins)