Tower Challenge

This project challenges students to construct a "cost-effective" tower that can support a designated load. In the project, students deal with the same problems faced by designers and engineers in the real world. They are given specific design parameters with which their structure must comply. Material, assembly, and production costs must be considered. Their structure must perform a specific task.

Just like engineers create a design to follow before starting a project, students are encouraged to devise a plan. By having a plan, students minimize the amount of "waste"--discarding index cards and using too many staples. I urged students to consider the "best" way to fulfill the eleven inch height requirement and to consider how a fold increased stability. I suggested that they make a simple model out of notebook paper to test different designs.

In this activity, teams comprised of two students design and construct a tower capable of holding a standard brick. An unlimited quantity of 4 x 6 inch index cards and staples may be used. The index cards represent building material costs, the staples represent assembly costs, and the folds in the index cards represent production costs. Every index card, staple, and fold costs a "$1.00."

There is an individual and a team component to the assessment. A maximum of fifty points was allotted to the team based upon the "cost" of the tower. A maximum of fifty points was awarded individually based upon questions dealing with the project.

Materials include an unlimited quantity of 4 x 6 inch index cards, staples, and a stapler. A standard brick is used for testing that has the dimensions of 8.5 inches x 3.25 inches x 2.75 inches. The brick weighs approximately 4.5 pounds.

Design parameters:

• The tower must be at least eleven inches tall.
• The tower must be capable of holding a brick for at least five seconds.
• The tower must be one unit that can be picked up and placed on the testing table.
• All folds must be discrete (no index cards rolled into tubes allowed).
• Index cards must be folded, not just bent.
• A separate count of staples, cards, and folds used during construction must be kept. This includes cards that were folded and discarded, etc.
• No initial testing of the tower with the brick is allowed.
• Every index card, staple, and fold used costs a hypothetical $1.00.

Designs to guide student inquiries:

• What is the best way to fulfill the eleven inch height requirement?
  1. Example One: Three cards are used. Cards overlap one half inch. Three staples are used to attach the card. In this configuration, the total height is eleven inches.

         material costs = $3.00
         assembly costs = $6.00
     
     
         total cost = $9.00/unit

  2. Example Two: Two cards are used. Cards overlap one inch. Two staples are used to attach the cards. In this configuration, the total height is eleven inches.

         material costs = $2.00
         assembly costs = $2.00
     
     
         total cost = $4.00/unit

  
  
  
  
  
  

• How does a fold increase stability?
  1. In example one, how many folds would you make and where would you place them to increase the stability of this unit?
  2. In example two, how many folds would you make and where would you place them to increase the stability of this unit?

  Folds represent production costs. The unit in example one is more costly than example two. By using folds to increase stability, could fewer units be used to complete the assigned task--reducing overall cost?

Assessment:

• A maximum of fifty points is awarded for the team assessment based upon the cost of the tower.

  Cost	Points	Cost	Points
  cost < $50	50	cost < $300	25
  cost < $100	45	cost < $350	20
  cost < $150	40	cost < $400	15
  cost < $200	35	cost < $450	10
  cost < $250	30	cost < $500	5
  cost > $500	0

• A maximum of fifty points is awarded for the individual assessment based upon the following questions.
  1. Draw a scale picture of your tower. Label all dimensions.
  2. How did you make the tower the required height? In other words, how many index cards did you use to meet the eleven inch height requirement? How were the cards configured?
  3. Describe what how you used folds in your design to achieve strength and stability. What else did you incorporate into your design to achieve this?
  4. How did you "cut costs" without sacrificing stability?
  5. Describe what part of your design was as successful as you predicted and what part was not.

  Form for submitting responses to questions two through five

  If using the form to submit your responses, you must turn in the answer to question one separately.

  This project was based upon an original activity developed by Dr. David Hoult, Senior Research Associate at MIT. My project source was Scientific American Frontiers Science Contests on-line.