London Bridge Is Falling Down . . . 
by Melanie Krill and Amber Pierzakowski
ITDPT - Section 3
 
Objective:  Using K'nex, the children will design and build a bridge, in pairs, that will span one foot and support at least five match box cars.  
 
Procedure:   
  • After forming groups, the children will experiment with structure design, balance, rigidity, and weight distribution based on previous discussions on bridge construction and physics.
  • They will draw the design and elect appropriate pieces from the K'nex sets.
  • Once the children have decided on a design, they will build it and test it.  They may try two different designs.  The design that has the best structural design and supportive ability will be graded.
  • The class will observe other designs and offer suggestions to their classmates.
 
Evaluation:  The students will be evaluated by how well the bridge supports its weight and the weight of the load  - AND - if they were successful in their replacement of London Bridge.
 
Feedback:  Children will receive feedback from a guest speaker, a real bridge engineer/builder.  He or she will offer suggestions as to how designs may be improved and how the designs would be made in the real world.  After the talk, the children will redesign their bridges to more sophisticated specifications.
 
Sources:  According to the National Science Education Standards for grades 5 -8, children should "identify appropriate problems for technological design; design a solution or product; implement a proposed design; evaluate completed technological designs or products; and communicate the process of technological design"(http://www.nap.edu/readingroom/books/nses/html/6d.html).  In these standards, students should consider: needs of the group, cost, materials, suitable tools and techniques, collaboration, plans, quality, improvements, implementation, and evaluation.   
 In the text, Science Plus, the unit "Structures and Design" presents lessons on planning the structure, response of structures to force, engineering structures, beauty in structures, and structures in the environment.  This unit would provide the background necessary to complete the London Bridge activity. McFadden. C. ed. (1993).  Science Plus.  Chicago, IL: Holt, Rinehart and Winston.