Lesson 1: When Is a Basketball a Substitute for Water?

Activity:  How Much Water Do You Need?

Download Activity 1:  Teacher Guide, Handouts, Visuals (.doc file)

Time Required:

  • Two and a half class periods


  • One copy of handouts 1, 3, and 4 for each student
  • One role card cut from handout 2 for each student
  • Calculator


  1. Explain that this lesson involves an examination of the choices people make regarding the use of water. Ask:
    • What are some of the uses for water in your daily life?
    • Rank items on the list in order of importance.
    • How much water do we need? How do you know?
    • Are there substitutes for water? In other words, could something else besides water satisfy any of the uses we have listed?
    • See suggested answers in teacher guide download linked above.
  2. Distribute Handout 1. Ask the students to examine the data on average uses per person/day. Discuss other categories of water use that are not included?
  3.  Assign students to calculate their families’ average monthly water use:
    • Assume 30-day months.
    • Remember that some activities, like laundry or showers, may not happen every day or may happen more than once in a single day.  Count up totals before multiplying by the average amount of water on the chart.
    • To calculate average monthly lawn usage, spread out over an entire year, students may use the following formula:
      • (# months lawn is watered X 30 days X 100 gallons/day) ÷ 12 months = avg. monthly lawn water usage.
  4. (# months lawn is watered X 30 days X 100 gallons/day) ÷ 12 months = avg. monthly lawn water usage.
    • Discuss
    • How much water does your family use?
    • How much water does your family need?
    • How do we know the difference between how much you need and how much you use?
    • Does your family waste water? How do we decide which uses of water are wasteful? 
    • What might cause your family to use less water?
    • What might happen to your family’s behavior if we changed the price paid for water? Suppose that the price of water is $0.0025 per gallon, or $.25 per 100 gallons.
      • Calculate your family’s average monthly water bill at this price:
    • Total water use _____________gallons x $0.0025 per gallon = $ ______________ water bill

  5. Explain that various surveys and estimates give us approximations of the amount of water used by the average person on the average day.
    • A United States Geological Survey report asserts that per capita household use of water averages 100 gallons per day.
    • The American Water Works Association estimates about 69.3 gallons per person per day for household use—not including outdoor uses like lawn watering. (www.drinktap.org)
    • The city of Nashville estimates residential use, including outdoor watering, to be about 70 gallons per person per day.
    • # people in your family_____  x 75 gal./day x 30 days) = _______gal./month
    • ________ gal./month X $.0025 = $__________average monthly bill.
    • Example:   family of 4: 4 x 75 x 30 = 9,000 gal. and an average water bill of $18 per month.
    • Let’s use 75 gallons per person per day as our average figure. If your family is “average,” how much water would you use in a month?
    • How does your real family’s use of water compare to the “aver­age” family use you just calculated? Is your use greater or smaller
    • How would you explain that difference?
  6. Divide the class into discus­sion groups of four. Distribute role cards (Handout 2) so that each group includes one of the following:  
    •   roles:
      •  a gardener
      • a car nut
      • a young parent
      • a busy executive
    • Direct students to read their role cards and list on the back of the card the most important uses of water to them in that role.
    • When students have listed several uses, direct them to put a star next to the use they value most.
    • Direct students to make a second list, brainstorming a few ways they could use less water. 
  7. Direct groups to conduct round-robin discus­sions in which each member
    • reads his or her role card aloud
    • lists the personal or family uses of water he or she finds most important
    • tells which use of water she or he would give up last
    • explains why his or her family uses water as it does
    • identifies some changes in water use the character could make and tells why the character would or would not be likely to make those change
  8. After the students have completed their discussions, conduct a class dis­cussion. Ask:
    • Did everyone in the group suggest the same changes? Why or why not?
    • Did anyone in the group not want to make any changes at all? Why?
    • Did anyone in the group want to make drastic changes in water use? Why?
  9. Distribute Handout 3. Announce that your region is suffering a drought. A severe water shortage is predicted for the coming summer. Direct each member of the group to review his or her role card and then complete the “New Water Policies” handout.
  10. Review the completed handout, by letting students share their answers.  Explain to the class that incentives are rewards or punishments for behav­ior. Prices are powerful incentives. A change in prices—including the price people pay for water—changes incentives and influences people’s decisions. Conduct a class discussion. Ask:
    • Which policies are likely to increase water consumption? Why?
    • Which policies are likely to reduce water consumption? Why?
    • Make a generalization about the price of water and how much people seem to “need”—or at least how much they use.
    • Do you think this generalization holds true for other things be­sides water?
    • Does the law of demand work the other way? What changes might the person in your role card make if the price of water were cut in half?
    • Let’s look back at our list of uses for water. Which of these uses would you consider to be an absolute “need,” in the sense that people cannot get by without it?
    • What about our other uses of water? Are they needs?
    • Why do you think that people generally use so much more water than the amount they drink?
    • Why do some people use more water than other people?
  11. Define:  Incentive:  reward or punishment for behavior
    • Look at your new policies handout.  What were the incentives for the new policies?  Did these incentives reward or punish reduced water use? Do these incentives force people to change their behavior? 
    • Which of these incentives – moral suasion or higher price – is likely to produce the greatest reduction in water use? 
    • Predict what will happen to the amount of water people use if the price of water goes up.
    • Predict what will happen to the amount of water people use if the price goes down.
  12. We have looked at incentives for people to make substitutions that reduce their household use of water.  With the idea of substitutions in mind answer these riddles about water use in other areas of life.
    • Recreation: When is a basketball an alternative to water?
    • Energy: When is coal an alternative to a waterfall?
    • Make up your own riddles. What other changes or substitutions can you think of?
  13. Summarize:  Why is raising the price of water a good way to reduce water use?
  14. Assessment:  Distribute Handout 4 to assess student learning.

Debbie Henney, FTE Director of Curriculum Receives Bessie B Moore Service Award

  Foundation for Teaching Economics is proud to announce that Debbie Henney, director of curriculum for the Foundation for Teaching…

FTE Pays Tribute to Jerry Hume

It is with deep sadness that we announce the loss of William J. Hume, known as Jerry Hume, former Chairman…

Why We Should Be Teaching Students Economic Literacy

Ted Tucker, Executive Director, Foundation for Teaching Economics October 26, 2022 More high schools are offering courses on personal finance…