Here's an exciting way to teach the Law of Diminishing Marginal Utility to your economics classes.
Time Required: 15 minutes
- Get a package of fun-size candy bars.
- In class, before introducing the idea of utility (satisfaction), get volunteers who say they would like to eat something with chocolate and peanuts in it.
- If there is more than one volunteer, have them choose a number between one and 100. Whoever is closest to your chosen number gets to be the volunteer.
- Place a desk in the front of the room facing the audience and have the student sit in it.
- Explain what utility means to the entire class.
- Draw a graph on the board, labeling the vertical side 'Utility' and the horizontal side 'Number of Candy Bars Consumed'.
- Place the numbers one to 10 on the vertical side of the graph.
- Explain to the volunteer that they are to eat one candy bar and then rate the utility they receive from one to 10. (10 is the highest utility)
- After each candy bar is consumed, have the volunteer rate their satisfaction and place a point on the graph that represents this.
- Continue until the student's satisfaction begins to drop. It is up to you how far you want this drop to go to prove the law.
- Thank the volunteer (and allow him/her to go get a drink of water.)
- It can be expensive to take the students' utility all the way to zero.