Price Elasticity of Supply (PES)

Active learning helps students move beyond abstract formulas by experiencing how supply responds to price changes in real time. Calculations become meaningful when paired with role plays and debates that reveal the human and physical constraints behind PES values.

• Year 10
• Economics
• 4 activities
• 20 min–40 min

Learning Objectives

1. Calculate the Price Elasticity of Supply (PES) for a given product using provided data.
2. Analyze how different factors influence the PES of various goods and services.
3. Evaluate the strategic implications of PES for a firm's production decisions.
4. Explain the relationship between the time horizon and the elasticity of supply for a product.

Problem-Based Learning

⏱ 25 min·Pairs

Pairs Calculation: PES Data Drills

Provide tables with price and quantity supplied data for five industries. Pairs compute PES for given changes, classify as elastic or inelastic, and note one factor per case. Pairs then swap tables to check calculations.

Prepare & details

Calculate the price elasticity of supply for various industries.

Facilitation Tip: During PES Data Drills, give pairs two minutes to calculate and compare their answers before revealing the correct solution as a class.

Setup: Groups at tables with access to research materials

Materials: Problem scenario document, KWL chart or inquiry framework, Resource library, Solution presentation template

• Analyze
• Evaluate
• Create
• Decision-Making
• Self-Management
• Relationship Skills

Problem-Based Learning

⏱ 40 min·Small Groups

Small Groups: Firm Response Simulations

Give groups scenarios of price increases in elastic and inelastic goods. They decide production changes, considering short-run and long-run factors, then graph supply shifts. Groups present one decision to the class.

Prepare & details

Evaluate why firms consider PES when planning production.

Facilitation Tip: In Firm Response Simulations, require each small group to document one factor that limited their ability to adjust output during the exercise.

Setup: Groups at tables with access to research materials

Materials: Problem scenario document, KWL chart or inquiry framework, Resource library, Solution presentation template

• Analyze
• Evaluate
• Create
• Decision-Making
• Self-Management
• Relationship Skills

Problem-Based Learning

⏱ 30 min·Whole Class

Whole Class: Elasticity Timeline Debate

Divide class into short-run and long-run teams. Present a policy raising prices; teams argue PES impacts and firm strategies. Vote on best response after structured rebuttals.

Prepare & details

Explain how the time horizon affects a product's supply elasticity.

Facilitation Tip: During the Elasticity Timeline Debate, assign a student timer to ensure each speaker has exactly one minute to avoid side conversations.

Setup: Groups at tables with access to research materials

Materials: Problem scenario document, KWL chart or inquiry framework, Resource library, Solution presentation template

• Analyze
• Evaluate
• Create
• Decision-Making
• Self-Management
• Relationship Skills

Problem-Based Learning

⏱ 20 min·Individual

Individual: PES Curve Sketching

Students receive price-quantity points for a good. They plot supply curves, calculate PES at two points, and label elastic/inelastic sections. Share sketches in a gallery walk.

Prepare & details

Calculate the price elasticity of supply for various industries.

Facilitation Tip: For PES Curve Sketching, provide graph paper with pre-labeled axes so students focus on elasticity shapes rather than axis scaling.

Setup: Groups at tables with access to research materials

Materials: Problem scenario document, KWL chart or inquiry framework, Resource library, Solution presentation template

• Analyze
• Evaluate
• Create
• Decision-Making
• Self-Management
• Relationship Skills

Teaching This Topic

Teachers should start with concrete, time-bound examples such as concert ticket resales to show how supply limits affect prices. Avoid over-reliance on textbook graphs early on; instead, have students derive the meaning of PES from raw data before they connect it to curves. Research suggests students grasp elasticity better when they first experience inelasticity through fixed constraints before exploring elastic cases, so sequence examples accordingly.

What to Expect

Students will articulate why some goods have elastic supply while others do not, use the formula correctly in calculations, and justify decisions based on supply timelines and industry constraints. Evidence of learning includes accurate PES calculations, reasoned debates, and correctly sketched supply curves.

Watch Out for These Misconceptions

Common Misconception

During PES Data Drills, watch for students who confuse the PES formula with the price elasticity of demand formula.

What to Teach Instead

During PES Data Drills, circulate and ask each pair to read the formula aloud before calculating, ensuring they use 'quantity supplied' not 'quantity demanded' in the numerator.

Common Misconception

During Firm Response Simulations, watch for students who assume all firms can adjust output instantly regardless of time frame.

What to Teach Instead

During Firm Response Simulations, hand each group a 'Short-Run Capacity Card' that limits their output to half the original amount to visibly demonstrate inelasticity.

Common Misconception

During Elasticity Timeline Debate, watch for students who claim PES values above 1 mean unlimited supply growth is always possible.

What to Teach Instead

During Elasticity Timeline Debate, require groups to cite at least one finite resource or regulation that would cap expansion for their chosen industry.

Assessment Ideas

Quick Check

After PES Data Drills, collect calculations and ask students to hold up a card with 'E' for elastic or 'I' for inelastic based on their result, revealing understanding in real time.

Discussion Prompt

During Firm Response Simulations, circulate and listen for accurate explanations of why capacity constraints made supply inelastic, using these observations to assess reasoning.

Exit Ticket

After the Elasticity Timeline Debate, ask students to write one sentence explaining how the bakery’s cake supply could become more elastic over time and one sentence naming a fixed factor that keeps it inelastic in the short run.

Extensions & Scaffolding

• Challenge: Ask students to find a real industry with inelastic supply and calculate its PES using published price and quantity data.
• Scaffolding: Provide a partially completed supply schedule with blanks for percentage change calculations to support struggling students during PES Data Drills.
• Deeper exploration: Have students research how advances in storage technology shifted the PES of perishable goods over the last century.

Key Vocabulary

Price Elasticity of Supply (PES)	A measure of how much the quantity supplied of a good or service responds to a change in its price. It is calculated as the percentage change in quantity supplied divided by the percentage change in price.
Elastic Supply	Supply where the PES is greater than 1. This means that the quantity supplied changes proportionally more than the price change, indicating producers can easily adjust output.
Inelastic Supply	Supply where the PES is less than 1. This means that the quantity supplied changes proportionally less than the price change, indicating producers face difficulties in adjusting output quickly.
Unit Elastic Supply	Supply where the PES is exactly equal to 1. The percentage change in quantity supplied is equal to the percentage change in price.
Time Horizon	The length of time over which a firm can adjust its inputs. In the short run, some inputs are fixed, while in the long run, all inputs can be varied.