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December Engineering Activity: Design a Better Cast

If you’ve ever had a broken bone and needed to wear a cast you know they can be heavy, unwieldy, itchy and SMELLY by the time they get removed. Design a better one!
December Engineering Activity: Design a Better Cast - Engineering

Your job in this activity is to design a better alternative! Using the engineering design process, you’ll identify the problem, brainstorm possible solutions, make sketches, create a prototype and test your solution! 

december engineering activity: design a better cast - engineering

Materials and Equipment: 

  • Half can of Play-Doh™ 
  • 4 popsicle sticks 
  • 6 to 8 recyclable materials of your choice: fabric, cotton batting, egg cartons, toilet paper or paper towel rolls, toothpicks, plastic bottles, milk cartons cut in pieces, rubber bands, straws, plastic tubing 
  • Digital scale 

The Challenge: Your prototype must have a mass of less than 300 grams and must be stable enough to hold the “broken bone” in place.  

  1. Take a look at your materials, these may represent any materials you would like, even ones that have not been developed yet, you just need to be able to describe the properties of the materials you choose for your cast alternative. Take a minute to play with the materials and think about how they work.
  2. Brainstorm solutions using the materials. Draw a sketch. Describe the properties of your chosen materials. Material Properties: _____________________________________________
  3. Using the provided materials and sketches, construct your prototype cast.  
  4. Test and evaluate your prototype. Since the materials you are using could feasibly represent any materials, the only physical test to determine whether or not the project is successful is to measure the mass of the prototype. Use the digital scale to determine the mass of your design. Does it meet the requirements of the challenge? If not, what could you remove to lower the mass?__________________________________________________________________________________________
  5. Evaluate your design based on its stability: Does it bend or move from side to side? What could you do to make it more stable? _____________________________________________
  6. Does your design solve the given problem? How could you make it better?_____________________________________________ 


 Keep working on your design until you’ve made the best cast possible with the available materials. How is it different than a cast you might get from the hospital? If you have different materials to use, what changes might you make to your design?  


  • december engineering activity: design a better cast engineering

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    Heather Sheridan

    Heather Sheridan P.E., PMP is a Civil Engineer and Project Manager at Black & Veatch in the Hydropower Department. Heather has a BS in Civil Engineering from the University of California, Davis with a focus on hydraulic structures and environmental design.