Lesson Plan

• Describe how price elasticity of demand varies along a straight‑line demand curve.
• Calculate elasticity at different points using \(E_P = \frac{dQ}{dP}\frac{P}{Q}\).
• Explain the revenue implications of elastic, unit‑elastic, and inelastic segments.
• Identify and label elastic, unit‑elastic and inelastic regions on a graph.
• Apply the concepts to solve short numerical problems.

• Projector and screen
• Whiteboard and markers
• Printed worksheet with the elasticity table
• Graph paper and rulers
• Calculators
• Handout of a straight‑line demand curve diagram
• Online quiz tool (e.g., Kahoot or Google Forms)

Begin with the question, “If a coffee shop lowers its price, will its revenue go up or down?” Recall that students already know the basic PED formula. State that today they will discover why the answer depends on where they are on the demand curve and what success looks like: correctly identifying the elasticity region and predicting the revenue effect.

1. Do‑now (5 min): Quick recall of the PED definition and formula on the board.
2. Mini‑lecture (10 min): Derive why \(E_P\) varies on a linear demand curve; introduce the three regions.
3. Guided practice (12 min): Work through the numerical illustration table, calculating \(E_P\) for the upper‑right, midpoint, and lower‑left points.
4. Graph activity (10 min): Students plot the three points on a straight‑line demand curve and label elastic, unit‑elastic and inelastic sections.
5. Revenue discussion (8 min): Link each region to total‑revenue outcomes; whole‑class examples.
6. Formative check (5 min): Kahoot quiz on region identification and revenue prediction.

Summarise that elasticity declines as price falls along a linear demand curve, and that this determines whether a price change raises or lowers total revenue. For the exit ticket, ask students to write one sentence describing the revenue effect of an elastic price cut. Assign the worksheet with additional points for homework.