Lesson Plan

• Describe the concept of joint supply and identify its key characteristics.
• Explain how a price change in one product influences the supply of its jointly‑produced counterpart.
• Analyse the effects of taxes, subsidies and export restrictions on jointly supplied markets.
• Construct and interpret a joint‑supply diagram showing shifts in supply curves.
• Apply the joint‑supply framework to real‑world examples such as beef & leather or oil & natural gas.

• Projector or interactive whiteboard
• Printed handout with key points and a blank joint‑supply graph
• Case‑study worksheets (beef & leather, oil & gas)
• Markers and whiteboard
• Calculator (optional) for profit‑maximising equation

Begin with a quick poll: “If the price of beef rises, what happens to leather supply?” Use the responses to link prior knowledge of supply shifts to the new concept of joint supply. Explain that today’s success criteria are to define joint supply, illustrate its diagram and evaluate policy impacts.

1. Do‑now (5 minutes): Students write a brief answer to the poll question and share with a partner.
2. Mini‑lecture (10 minutes): Define joint supply, outline key features and give common examples.
3. Diagram activity (12 minutes): In pairs, students draw a joint‑supply diagram for oil and natural gas, showing how a price rise in oil shifts the gas supply curve.
4. Policy analysis (10 minutes): Small‑group discussion on how a tax on crude oil or a subsidy to timber would affect the related product, referencing the earlier diagram.
5. Case‑study application (8 minutes): Work through the beef‑leather example, answer one of the practice questions.
6. Check for understanding (5 minutes): Exit ticket – one sentence explaining the profit‑maximising condition for jointly supplied outputs.

Recap the definition of joint supply, the inter‑dependence of supply curves, and the policy implications discussed. Collect the exit tickets to gauge understanding, and assign homework: complete the remaining practice questions in the worksheet.