Set in the late 1950s, this is the moving story of a young boy whose father operates a ferryboat between Michigan's Upper and Lower peninsulas. As young Mark witnesses the building of the new Mackinac Bridge, he is torn between family loyalty and eager anticipation. He can't help being awestruck by the majesty of the five-mile-long bridge that will connect the two peninsulas and change the lives of so many. But the Mighty Mac will also put Mark's father out of business. As his father struggles with the flow of progress, Mark dreams of future bridges he will build. Details of the complex construction of the bridge will fascinate children as they learn an important part of America's history and come to understand the meaning of change. The Mackinac Bridge Authority provides history notes at the back of the book.


design challenge


How can we design a bridge a bridge to connect ______ to ______? Consider Petoskey to Harbor Springs, Charlevoix to Beaver Island, or another location. Try to make this real world to be able to pull the length to apply scale proportion and quality. 


​Simply Suggestions:

  • Popsicle sticks

  • Toothpicks

  • Pipeceaners

  • String

  • Cardboard

  • Hot glue

  • Elmers glue

  • Binderclips


Who will be using this bridge? Is the target audience driving cars, walking, or riding bikes? It will also need to fit the surrounding environment to be aesthetically pleasing. Will it be in the woods and in nature, or the city, should it be an artistic representation? Students should also consider the native animals in the area and how this bridge might affect their lives as well. 


Your Choice: 

  • Length

  • Time

  • Hold a specified amount of weight

  • Width for a specific audience

PE aligned

Including, but not limited to: 

  • CCC: Scale, proportion, and quantity

  • SEP: Developing Models


Students will begin to draw on background knowledge and experience to think about ways to approach the challenge and solve the problem. Allow class discussion of considerations and ideas. Students will have various experiences with bridges of all kinds. Consider showing pictures of the different kinds, look for similarities and differences between bridges. Encourage them to look at structure, foundation, span, width, supports, and visual appeal. 

If interested, spend some time helping students discover the strength of a triangle. 


In teams, students will draw a model of the bridge they want to build. Have students first consider the way they want it to look with specific measurements to the scale of the distance needing to traverse, as well as heights. Then have teams connect to share their model and discuss the choices they made. 

Once they have a clear model of the design, they need to consider the materials they can use to complete this. Special attention needs to given to a stable base and support across the middle. Materials should then be reflected in their plan. 


It is beneficial to have student roles in designing the bridges some to consider are project manager, structural engineer, data manager, materials engineer, etc. Please try to have these be real roles as opposed to time keeper, and materials getter. 

Teacher Tip: Depending on the age of your students, you may need to manage the glue gun or change the way they assemble their bridges. This can be a logistical challenge with limited adults and limited glue guns. 


This should be a formalized testing day, so that a constraint is time and students have a deadline for their project (which reflects a real piece of project management). Also it creates real attention for each team's design and validating their work. Another consideration is that if bridges tend to break, and so they are not able to do formal repetitive testing. They can do smaller tests for weight and length as they go through the design. 


Discuss and compare the various level of success for students. In using a length constraint it helps all students be success in some aspect of bridge building. Rebuilding is not always possible with this challenge, but it is critical to give discussion and attention to how students would improve their design. Maybe there is a way that they can redesign and test on a digital program. 

additional texts


model / sim