Rehearse Your Lesson with Virtual Students: O’Level Chemistry (Polymerisation)

The Compelling Method: Simulate → Reflect → Refine

Step 1: Simulate – Rehearsing the Lesson

Topic: Polymerisation (addition polymerisation, using ethene → poly(ethene) as the main example).
Class: O’level Chemistry, Year 10, 35–40 students, mixed ability.

Teacher’s AI Prompt:

“You are a group of O’level Chemistry students in Bangladesh. I am teaching a lesson on polymerisation. Some of you understand quickly, some struggle with chemical equations, and one or two get distracted. Please respond as students would — asking questions, making mistakes, and sometimes going off task.”

Dialogue Excerpt:

• Teacher: “Polymerisation is when small molecules, called monomers, join to make a long chain called a polymer. For example, many ethene molecules join to make poly(ethene).”

  • Student A: “Sir, does that mean one ethene molecule becomes a polymer?”

  • Student B: “Why do you write it in brackets with an ‘n’? What is n?”

  • Student C: “If it’s just ethene joining, why don’t the double bonds stay?”

  • Student D (off-task): “Sir, is plastic bad for the environment? My father says we should ban it.”

How to Do This Stage

What do I ask the AI?

• “Role-play O’level Chemistry students learning polymerisation.”

• “Include confusions about double bonds, the ‘n’ in the formula, and real-life issues.”

• “Ask me tough and off-topic questions that could throw me off.”

What do I ask myself?

• Did these confusions line up with what I’ve seen in past lessons?

• Which explanations felt shaky when I tried them out loud?

• How can I link the off-task environmental question to the chemistry?

How do I turn raw AI dialogue into insights?

• Misconception: students think one monomer becomes a polymer.

• Misconception: students don’t understand the notation “n.”

• Misconception: double bond breaking is invisible and mysterious.

• Off-task: environmental concerns can be reframed as a real-world application (pros/cons of polymers).

Step 2: Reflect – Analysing the Simulation

From the transcript:

• Misconception 1: One molecule = one polymer. (Students don’t grasp “repeated many times.”)

• Misconception 2: Brackets and “n” are confusing. (Abstract symbolism not well connected to reality.)

• Misconception 3: Why double bonds break. (Students miss that the double bond provides the reactive site.)

• Engagement: Off-task but valuable: environmental issues around plastics → can be a hook.

• Extension opportunity: Link to other polymers (PVC, polystyrene) and their different properties.

How to Do This Stage

What do I ask the AI?

• “Explain polymerisation at O’level using analogies.”

• “List common misconceptions about the ‘n’ and the brackets.”

• “Suggest real-world examples I can use to engage students.”

• “Give me one extension question for high achievers.”

What do I ask myself?

• Did I assume too much prior knowledge (like understanding of bonding)?

• Do I need to show the process step-by-step instead of jumping to the final formula?

• How can I keep weaker students engaged while still stretching the stronger ones?

How do I turn raw AI dialogue into insights?

• Plan analogy: “Monomers are like Lego bricks — one by itself isn’t a toy, but many joined together make something useful.”

• Add explicit visual of double bond opening up.

• Clarify “n”: write “repeat n times” and use examples (n=10, n=1000).

• End lesson with real-world discussion: why polymers are both useful and problematic.

Step 3: Refine – Updating the Lesson Plan

Original Plan (before rehearsal)

1. Starter: Review bonding in alkenes.

2. Explain polymerisation: ethene → poly(ethene).

3. Show structural equation.

4. Students copy notes.

5. Recap with short quiz.

Refined Plan (after rehearsal)

Starter (5 mins):

• Quick quiz: “What’s special about alkenes compared to alkanes?” (elicits double bond knowledge).

• Pose the challenge: “How can we join many small molecules to make something bigger?”

Teacher Input (10 mins):

• Step-by-step: draw ethene, circle double bond, show bond breaking.

• Show two ethene molecules joining, then three, then “n.”

• Analogy: Lego bricks joining into a long chain.

• Clarify notation: brackets + “n” = repeated many times.

Guided Practice (10 mins):

• Students draw polymerisation of ethene → poly(ethene).

• Teacher circulates, correcting errors with double bonds and “n.”

• Ask probing Q: “Why don’t polymers still have double bonds?”

Independent Task (10 mins):

• Worksheet: write equations for polymerisation of propene and chloroethene.

• Extension: predict properties of poly(chloroethene) vs poly(ethene).

Plenary (5 mins):

• Whole-class Q: “Why are plastics both a blessing and a curse?”

• Connect chemistry to environment (strength, durability, waste issues).

Why the Refined Plan is Stronger

• Misconceptions tackled head-on → notation, “n,” and double bond breaking explained visually + with analogy.

• Greater clarity → step-by-step build avoids overwhelming students.

• Engagement improved → Lego and plastics examples link to student experience.

• Deeper challenge → extension pushes towards polymer properties and applications.

Original vs Refined Lesson Plan: Polymerisation (O’Level Chemistry)

Why This Matters for O’Level Teachers

Polymerisation is a classic stumbling block: the chemistry is abstract, the notation confusing, and the real-world issues emotionally charged. By running the simulate → reflect → refine cycle with AI, teachers can:

• Anticipate the common errors before they spread.

• Reduce lesson stress and re-explaining mid-class.

• Save planning time by surfacing misconceptions in advance.

• Build student engagement with real-world connections.

Final Thought

Polymerisation lessons don’t have to dissolve into confusion about “n” or why double bonds disappear. By simulating student responses in advance, reflecting on the weak points, and refining your plan, you walk into class confident that your students will see the chemistry clearly — and understand why it matters in the world around them.

👉 Next in this series: Spotting Common Misconceptions with AI