Target Grade Level:

4th Grade and 7th Grade


One 60-minute lesson or two 30-minute lessons 


Students will understand the law of supply and demand and how it affects the cost of goods and services. Students will use the law of supply and demand to explain why the market price of crops and livestock fluctuates.


  • Computer, internet connection, and projector to show video
  • Copies of Supply and Demand Worksheet for each group

Suggested Companion Resources (books, websites, etc.)

  • Hudsucker Proxy video:
  • Loewen, N., & Jensen, B. (2004). Lemons and Lemonade: A Book About Supply and Demand. Minneapolis, Minn.: Picture Window Books.
  • Larson, J. (2010). Who’s Buying? Who’s Selling? Understanding Consumers and Producers. Minneapolis Lerner Publications.

Vocabulary (with definitions)

  • Supply – the amount of product or service available for people to buy
  • Demand – how much of a product or service people are willing to buy
  • Product – anything made, especially to be sold to others
  • Cost amount of money paid for a good or service

Background – Agricultural Connections (what would a teacher need to know before teaching this lesson):

The teacher must understand the law of supply and demand and how this affects the price of crops and livestock.

Interest Approach or Motivator:

Show the Hudsucker Proxy video.  Ask students to describe what they saw in the video

  • What happened when no one was buying the hula-hoops? (The price went down)
  • How would you describe the supply of hula-hoops in the store before they were being bought? (High)
  • As kids started buying hula-hoops, what happened to the supply? (It went down)
  • As kids started buying hula-hoops and there were fewer hula-hoops available, what happened to the price of the hula-hoops? (It went up)

Procedures (outline the main points, step by step activities, and the full content to be presented to students)

  1. Introduce students to vocabulary and refer to video for examples
    • What product was being sold in the video? (hula-hoops)
    • What was the toyshop’s supply like in the beginning? (High…Many hula hoops)
    • What was the demand for hula-hoops like at this point? (Low)
    • What happened to the cost of the hula-hoops when supply was high and demand was low? (The price went down)
    • What happened to the demand for hula-hoops after the kids saw the boy doing all of his tricks with it? (Demand went up)
    • When demand for the hula-hoops went up, what happened to the supply of hula-hoops? (It went down…There were fewer hula hoops available)
    • When demand for the hula-hoops was high and the supply of hula-hoops was low, what happened to the cost of the hula-hoops? (It increased)
  2. Explain to students that supply can affect the cost of goods and service. Supply and Cost have an inverse relationship. This means when one goes up, the other goes down or when one goes down, the other goes up. When supply is high, is low…When supply is low, goes up.
  3. Explain to students that demand also affects cost, but it has a direct relationship. High demand leads to higher prices and low demand leads to lower prices.
  4. Ask students: Since most of us aren’t buying hula hoops every day, can you think of some goods or services that we buy on a regular basis where the costs may be determined by supply and/or demand? (gas, groceries, corn, soybeans, beef, pork) Use the example of the recent avian flu epidemic: the cost of eggs has recently doubled because chickens that lay eggs have died resulting in a low supply of eggs. Due to a low supply and consistent demand, the cost of eggs has increased.
  5. Divide students into groups and have them work together to complete the Supply and Demand Worksheet (see Essential Files). Give students 10 minutes to complete worksheets and then discuss answers.

Essential Files (maps, charts, pictures, or documents)


Extension Activities (how can students extend learning outside of the classroom? This could include assignments they do outside of class.)


Amy Kloberdanz


National Agriculture Literacy Outcomes

  • Describe how supply and demand impact the price of agricultural goods (Gr. 3-5)
  • Explain how prices for agricultural goods are determined (Gr. 6-8)

Iowa Core Standards

  • Social Studies
    • SS.4.14. Explain the reasons why the costs of goods and services rise and fall.
    • SS.7.19. Explain how external benefits, costs, supply and demand, and competition influence market prices, wages, and outcomes.
    • SS.7.27. Analyze the role that Iowa plays in contemporary global issues.




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