Economics · Grade 10 · Markets in Action: Supply and Demand · Term 1

Price Elasticity of Supply

Students will calculate and interpret price elasticity of supply, understanding how producers respond to price changes.

• Ontario Curriculum Expectations
• HS.EC.2.3

About This Topic

Elasticity measures how much consumers and producers respond to changes in price. Students learn why the demand for some goods, like insulin or gasoline, is inelastic (insensitive to price), while others, like luxury vacations, are highly elastic. This concept is vital for understanding business strategy and government taxation. For instance, students analyze why governments often place 'sin taxes' on products like cigarettes, which have inelastic demand.

In the Ontario curriculum, elasticity helps students understand consumer behavior and the impact of price changes on total revenue. It also touches on how the availability of substitutes and the proportion of income spent on a good influence sensitivity. This topic benefits from hands-on investigations where students analyze real-world data and predict consumer reactions to price hikes.

Key Questions

1. Explain the factors that determine the price elasticity of supply for a product.
2. Analyze how time horizons (short run vs. long run) affect supply elasticity.
3. Compare the implications of elastic versus inelastic supply for market adjustments.

Learning Objectives

• Calculate the price elasticity of supply for various goods and services using given price and quantity data.
• Analyze the factors influencing the price elasticity of supply, such as production capacity and time horizon.
• Compare the market outcomes when supply is elastic versus inelastic in response to price changes.
• Explain how producers' ability to adjust output affects the responsiveness of supply to price fluctuations.

Before You Start

Introduction to Supply

Why: Students need to understand the basic law of supply and the relationship between price and quantity supplied before analyzing its elasticity.

Calculating Percentage Change

Why: The calculation of price elasticity of supply relies on understanding how to compute percentage changes in price and quantity.

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 that is very responsive to changes in price. A small change in price leads to a larger percentage change in quantity supplied. PES is greater than 1.
Inelastic Supply	Supply that is not very responsive to changes in price. A change in price leads to a smaller percentage change in quantity supplied. PES is less than 1.
Unit Elastic Supply	Supply where the percentage change in quantity supplied is exactly equal to the percentage change in price. PES is equal to 1.
Time Horizon	The length of time producers have to respond to a price change. Generally, supply becomes more elastic over longer time horizons.

Watch Out for These Misconceptions

Common Misconception

Elasticity is the same as the slope of the demand curve.

What to Teach Instead

While related, elasticity changes along a linear demand curve. Using a 'rubber band' analogy and plotting different points on a graph helps students see that sensitivity can vary even if the line is straight.

Common Misconception

If a price goes up, total revenue always goes up.

What to Teach Instead

If demand is elastic, a price increase will actually cause total revenue to fall because consumers drop off so quickly. Having students calculate 'Price x Quantity' for different scenarios helps them see this mathematical reality.

Active Learning Ideas

Inquiry Circle: The Sin Tax Analysis

Groups research the impact of Canadian taxes on tobacco or sugary drinks. They must explain why these specific items were chosen based on their elasticity and whether the tax successfully reduced consumption or just increased tax revenue.

45 min·Small Groups

Think-Pair-Share: Necessity vs. Luxury

Students are given a list of 10 items (e.g., WiFi, milk, designer shoes, salt). They must rank them from most inelastic to most elastic and justify their choices based on the availability of substitutes.

20 min·Pairs

Simulation Game: The Revenue Maximizer

Students act as consultants for a local transit authority. They are given data on ridership and must decide whether to raise or lower fares to increase total revenue, discovering the relationship between elasticity and revenue through trial and error.

40 min·Small Groups

Real-World Connections

• Oil producers in Alberta face challenges in quickly increasing supply when global oil prices rise due to the long lead times and significant capital investment required for new extraction and transportation infrastructure. This makes their short-run supply relatively inelastic.
• Farmers growing seasonal produce, like strawberries, experience more elastic supply in the long run. Once the growing season begins, they can adjust their harvesting and distribution efforts to respond to higher prices, but they cannot immediately plant more acres in response to a sudden price spike.
• Manufacturers of smartphones often have more elastic supply compared to producers of heavy machinery. They can often ramp up production lines or adjust inventory levels more quickly to meet changes in consumer demand and price, especially if they have readily available components and flexible labor.

Assessment Ideas

Quick Check

Provide students with a scenario: 'The price of artisanal cheese increased by 15%, and the quantity supplied increased by 30%.' Ask them to calculate the PES and state whether the supply is elastic, inelastic, or unit elastic. Then, ask them to identify one factor that might explain this elasticity.

Discussion Prompt

Pose the question: 'Imagine a sudden surge in demand for electric vehicles. Discuss how the price elasticity of supply for EV batteries might differ in the short run (next 6 months) versus the long run (next 5 years). What factors would contribute to this difference?'

Exit Ticket

Students receive a card with a product (e.g., concert tickets, wheat, custom-made furniture). They must write: 1. Their prediction for the PES of this product. 2. One reason for their prediction, referencing factors like production time or resource availability.

Frequently Asked Questions

Why is the demand for gas inelastic in Canada?

In many parts of Canada, there are few substitutes for driving due to long distances and limited public transit. Because people 'need' gas to get to work, they continue to buy it even when prices rise, making it a classic example of inelastic demand.

How do businesses use elasticity?

Businesses use it to set prices. If they know their product has many substitutes (elastic), they are careful not to raise prices. If they have a unique product (inelastic), they have more 'pricing power.' This is a key part of the Grade 10 business and economics expectations.

What are the best hands-on strategies for teaching elasticity?

The best strategies involve real-world 'sensitivity tests.' Ask students to vote with their feet: 'If the price of pizza doubled, would you still buy it? What if it tripled?' By physically moving to different sides of the room, students see the 'drop off' in demand visually, which perfectly illustrates the concept of elasticity.

What factors make demand more elastic?

Demand becomes more elastic when there are many substitutes available, when the item is a luxury rather than a necessity, when it represents a large part of your budget, or when you have a long time to adjust to the price change.