Discover Engineering in Central Texas

Build a Bridge

Grade Level:  Middle School and High School, 5^th-12th

Related classroom topics:  Civil Engineering, Force

Supplies Needed: 

Divide students into groups of 3-5.  Each group will need: 

·        Copier Paper (100 sheets total)

·        Plastic Straws (50 total)

·        Marshmallows (1 bag total)

·        Lag Washer (50-100 total depending on age of students)

Procedure: 

1.      Give each group 10 dollars of monopoly money to purchase supplies to build a bridge.

2.      The bridge must span 10 inches with two thick textbooks supporting each end of the bridge.

3.      The students have 15-20 minutes to design and build their bridges.

4.      Each bridge is tested in front of the whole class.

5.      The bridges are tested using lag washers, or any other weight you want to use

6.      Allow the students to spread the testing weight over the bridge evenly.

7.      A summary of the “costs” of supplies is given:

a.       Paper = $1

b.      Straws = $3

c.       Marshmallows = 50 cents        

Extensions:  Incorporate different materials with different costs to build lots of different kind of bridges.  Possibly provide a slideshow before the competition starts to show some of the different bridges already built around the world. 

Related topics you could discuss:  Engineering design, Construction and analysis, Teamwork, Force, Stability, cost control, compromise, deadlines, testing

Hints/Tips:  Pre-build a truss folded version out of 1 or 2 pieces of paper.  Show students that the cheaper material may also be the strongest when engineering concepts are used in design.  It also shows how education can make what seems impossible work.

Experiment Submitter:  Michael Fisher, Oregon