Law of Supply
Unit 2 · Lesson 2.4 · Last updated June 2026
A 45-minute lesson where students draw on their hat firm experience to learn the law of supply, practice graphing changes in quantity supplied, and tackle mixed supply and demand scenarios.
Overview
In this lesson, students continue to learn about the product market model. They build on their knowledge of the law of demand and prior participation in simulations to learn about the law of supply, and practice illustrating changes in quantity supplied.
Learning Objective
- Explain the relationship between price and quantity supplied.
Create a free account, or log in.
Get full access to materials, the complete lesson sequence, aligned standards, and every lesson across all units.
Already a member? Sign in here.
Materials
- Instruction Slides (display during class period)
- Student Handout pp. 4–7 (1 copy per student)
- Summarizer pp. 8–9 (1 copy per student)
Lesson Sequence
Slides 2–6
- Display Slide 2 and distribute 1 copy of Student Handout. Direct students to work individually to complete activator problems 1 and 2 and write their response to question 3. After 3 minutes of individual work, click to reveal and review the answers using Slides 3 and 4. (Additional educator tips and suggested answers are in the notes section throughout Instruction Slides.)
- Proceed to Slide 5. Explain the connection between the law of demand and sales.
- Display Slide 6. Introduce the learning objective for the lesson.
Slides 7–29
- Progress through Slides 7–8. In pairs, students discuss the review questions related to the Hat Firm Simulation (Lesson 2.3) on Slide 8. After 1 minute, click to reveal the correct responses and review as needed.
- Proceed to Slide 9. In pairs, students reflect on the Coffee Market Simulation (Lesson 2.1) and the model of supply and demand. After 1 minute, click to reveal the correct responses.
- Display Slide 10. Introduce the law of supply and click to reveal the movements along the supply curve. Note to students that there is a direct (positive) relationship between the price of a good or service and a firm's willingness to supply it. Alert students to the stumbling block (as indicated by the yellow warning graphic): it is important that students refer to a change in "quantity supplied," not "supply," when the only variable is product price. This is a common area of confusion, and precision now will make things much clearer in the future.
- Proceed to Slide 11. Direct students to synthesize the law of supply with their partners and then write responses on Student Handout, question 4.
- Guide students through two practice examples (and solutions) in Slides 12–17, pointing out that as price increases, quantity supplied increases and vice versa. Students sketch the changes on Student Handout for each example.
- Display Slide 18. Alert students to the stumbling block: the law of supply is typically more challenging for students. Reinforce that students can use their experience as a hat-making firm to help frame problems that relate to the law of supply. (Throughout the course, encourage students to "put on your Firm Hat" when faced with supply questions.)
- Advance to Slide 19. Direct students to complete "Rate your understanding," questions 6–7, on Student Handout.
- Advance through Slides 20–21. Instruct students to work for 8 minutes with a partner to complete practice questions 1–4 on Student Handout. Remind students that questions 1–4 are all examples of a change in quantity supplied and therefore all movement takes place along the supply curve. Students should be wearing their "Firm Hat" when thinking about these problems. After 8 minutes, review answers as a class using Slides 22–24.
- Proceed to Slide 25. Alert students that the next practice section may be a challenge — questions 5–7 are a mix of supply and demand scenarios. Remind students to read carefully and make changes along the appropriate curve. Students work with a partner on questions 5–7 for 6 minutes.
- Review answers as a class using Slides 26–29. If students finish early, encourage them to complete extension questions 8–11. Note: Any change in price will affect both quantity supplied and quantity demanded, but each question focuses on buyers or sellers — student graphs should reflect the change for the relevant group.
Slides 30–33
- Display Slide 30. Tell students to put Student Handout and any other notes away.
- Proceed to Slide 31. Distribute Summarizer to each student. Direct students to write their name next to "Scenario Creator" and take 1 minute to write their own example of a scenario that illustrates the law of supply OR the law of demand (does not need to be a real-world example).
- Advance to Slide 32. Instruct students to swap their copy of Summarizer with a classmate and write their name on their partner's copy next to "Scenario Solver." The Scenario Solver answers all 4 questions on their partner's copy and models the changes on the graph. Upon completion, students return their partner's copy, review responses together, and discuss areas of confusion.
- Display Slide 33. With 1 minute remaining, students respond to the "Gauge Your Understanding" questions (6 and 7) on their original copy of Summarizer.
- Collect Summarizer from students to review for common errors or sources of confusion.
Aligned Standards
Voluntary National Content Standards in Economics
What Educators Are Saying
They spend more time interacting with the material than just writing notes. There is a lot of practice embedded throughout the lesson. I have also never taught law of demand and demand shifts separate — this seemed to help them grasp the concept that price changes don't change overall demand.
Impossible to improve this! I have used quite a few of your lessons and will continue to do so. You are impacting so many students (and teachers) and I cannot thank you enough!
Incredibly helpful with real world examples and easy to implement!