Demand: Definition and Law

Active learning works for this topic because the Law of Demand describes real-world behavior that students experience daily. When students physically participate in simulations or discussions, they connect abstract economic rules to their own decision-making, making the concept stick better than through lecture alone.

• Grade 9
• Economics
• 3 activities
• 20 min–45 min

Learning Objectives

1. Explain the Law of Demand, including the inverse relationship between price and quantity demanded.
2. Analyze how changes in price affect a consumer's purchasing power and the quantity of a good or service they are willing and able to buy.
3. Differentiate between a movement along the demand curve (change in quantity demanded) and a shift of the demand curve (change in demand).
4. Identify at least three non-price determinants of demand and explain their impact on consumer preferences.

Simulation Game

⏱ 30 min·Whole Class

Simulation Game: The Classroom Auction

Auction off a desirable item (like a snack or a 'no-homework' pass) starting at a very high price and lowering it gradually. Students record how many people are willing to 'buy' at each price point, then use that data to plot a real demand curve on the board.

Prepare & details

Explain the Law of Demand and its real-world implications.

Facilitation Tip: During The Classroom Auction, set clear starting bids and bidding increments so students focus on the relationship between price and quantity demanded rather than winning the item.

Setup: Flexible space for group stations

Materials: Role cards with goals/resources, Game currency or tokens, Round tracker

• Apply
• Analyze
• Evaluate
• Create
• Social Awareness
• Decision-Making

Think-Pair-Share

⏱ 20 min·Pairs

Think-Pair-Share: Substitutes and Complements

Give students a list of Canadian products (e.g., Tim Hortons coffee, winter tires, maple syrup). In pairs, they identify one substitute and one complement for each and explain how a price hike in the original product would affect demand for the others.

Prepare & details

Analyze how a change in price affects consumer purchasing power.

Facilitation Tip: For Substitutes and Complements, provide real-world examples like coffee and creamer or smartphones and phone cases to ground the discussion in familiar contexts.

Setup: Standard classroom seating; students turn to a neighbor

Materials: Discussion prompt (projected or printed), Optional: recording sheet for pairs

• Understand
• Apply
• Analyze
• Self-Awareness
• Relationship Skills

Inquiry Circle

⏱ 45 min·Small Groups

Inquiry Circle: The 'Trend' Tracker

Groups choose a recent viral trend (like a specific sneaker or a TikTok-famous snack). They investigate what caused the demand shift (celebrity endorsement, social media, etc.) and present a 'Demand Shift' poster showing the original and new demand curves.

Prepare & details

Differentiate between a change in quantity demanded and a change in demand.

Facilitation Tip: When running The 'Trend' Tracker, give students a two-week window to collect data so trends are visible but not overwhelming to analyze.

Setup: Groups at tables with access to source materials

Materials: Source material collection, Inquiry cycle worksheet, Question generation protocol, Findings presentation template

• Analyze
• Evaluate
• Create
• Self-Management
• Self-Awareness

Teaching This Topic

Teachers approach this topic by grounding abstract concepts in concrete experiences. Avoid starting with formal definitions; instead, let students observe patterns first through activities like auctions or trend tracking. Research suggests that when students generate examples themselves, their understanding of demand becomes more flexible and applicable to new situations. Emphasize the difference between 'wanting' and 'demanding' early to prevent common misconceptions.

What to Expect

Successful learning looks like students confidently distinguishing between price effects and non-price determinants of demand. They should use evidence from activities to explain why demand curves shift or move along the curve, and apply these ideas to everyday situations like sales or pricing changes.

Watch Out for These Misconceptions

Common Misconception

During The Classroom Auction, watch for students who confuse a bid increase with a shift in demand rather than a movement along the demand curve.

What to Teach Instead

After the auction, have students draw the original and new quantity demanded points on a large floor-grid with string. Ask them to explain why the curve did not shift, only the point moved.

Common Misconception

During Substitutes and Complements, listen for students who say 'I want it, so demand goes up' without considering ability to pay.

What to Teach Instead

Use the luxury car versus used car example during the discussion. Ask students to consider income levels and write a sentence explaining why one group demonstrates demand while the other does not.

Assessment Ideas

Quick Check

After The Classroom Auction, give students a half-sheet with scenarios like 'The price of movie tickets fell by $5' or 'A new study links popcorn to longer life.' Ask them to identify whether each is a change in quantity demanded or a change in demand and explain using auction observations.

Exit Ticket

During The 'Trend' Tracker, have students complete an exit-ticket with the Law of Demand in their own words on one side and two factors that could increase demand for their favorite snack on the other, explaining how each factor affects demand.

Discussion Prompt

After Substitutes and Complements, pose the discussion question: 'If the price of streaming doubled, how would this affect your entertainment budget?' Have partners discuss how this differs from a new streaming service entering the market, using their understanding of purchasing power and substitutes.

Extensions & Scaffolding

• Challenge students who finish early to create a new auction scenario with a good that has many substitutes and predict how demand will respond to a price increase.
• For students who struggle, provide a partially completed demand curve on graph paper with labeled axes to help them plot data points from The 'Trend' Tracker.
• Deeper exploration: Have students research how demand for a product like electric vehicles changed over the past decade and identify which non-price factors shifted the demand curve most significantly.

Key Vocabulary

Law of Demand	An economic principle stating that, all other factors being equal, as the price of a good or service increases, the quantity demanded will decrease, and conversely, as the price decreases, the quantity demanded will increase.
Quantity Demanded	The specific amount of a good or service that consumers are willing and able to purchase at a particular price during a given period.
Demand Curve	A graphical representation showing the relationship between the price of a good or service and the quantity demanded at each price, typically sloping downward.
Change in Quantity Demanded	A movement along the existing demand curve caused solely by a change in the price of the good or service.
Change in Demand	A shift of the entire demand curve to the right or left, caused by factors other than the price of the good or service itself.