Senior Think Like an Engineer Journey


Take the Harmless Holder Design Challenge


Find out how engineers solve problems with the Design Thinking Process. Then, take on a design challenge to engineer a soda holder that helps protect animals and sea life!

Activity Details

Set-Up:  Plastic rings are great for carrying cans, but they're a real problem when they become trash on a beach or in the ocean.   When people litter, garbage like the plastic rings become harmful for birds, turtles, fish, and other animals.   When the plastic ends up in the ocean, it breaks down into debris, called microplastics. Microplastics pollute the ocean and are often eaten by sea creatures, who may then be eaten by humans!

For this design challenge, follow the steps of the Design Thinking Process to engineer a prototype for a new and better way to hold a six-pack of soda cans that isn't harmful to animals. A prototype is a quick way to show an idea to others or to try it out. The Design Thinking Process is the steps engineers go through to solve problems. They: identify the problem, brainstorm and plan, build, test, and improve.

Time needed: 60 minutes

Materials needed:

  • 1 large piece of cardboard (1 x 2 ft or more)
  • 8 paint stirrers or dowels
  • Wax paper
  • Another type of paper, like white or newspaper
  •  20 rubber bands
  • 1 meter (39 inches) of string
  • 6 cans of soda
  • Duct or packing tape
  • Scissors
  • Paper
  • Pencil

Note: If you’re missing a material or have another idea for something that might be useful, free feel to test them. Trying out different ideas to see what works is something engineers do!


To get started, Then, identify the problem you're trying to solve: engineer a soda holder that isn’t harmful to animals.

Then, spend a few minutes brainstorming the design of your holder. Sketch your ideas on sheets of scratch paper to create a plan that keeps in mind the criteria and constraints.

  • Criteria are things the design needs to accomplish. They’re the goals for a prototype. The criteria for the challenge is that your holder must: 1) hold six cans, 2) be easy to carry, 3) be safe for animals, and 4) be convenient for people to use.
  • Constraints are ways the design is limited. For example, there might only be a certain amount of time to build the prototype or a limited amount of materials to make it. The constraint for this challenge is that you can only use your challenge materials, including the cardboard, paint stirrers or dowels, wax paper, other paper, rubber bands, and string. If you also gathered other materials to use, feel free to try them out!

It might help to ask yourself questions like:

  • How can you hold six cans together?
  • How could you arrange the cans? On their sides? Stack them?
  • How can you easily remove the cans?
  • How will you carry the holder?
  • How are you going to keep the cans from falling out of the holder?

Once you have some ideas, choose one to turn into a prototype.

Then, use your plan and materials to build your holder. As you build, feel free to try lots of different ideas to see what works and doesn't work. Remember, the goal is to practice thinking like an engineer, NOT to make a perfect holder!

When you think you have a finished holder, test it and see how well it works!

Before you start testing, what do you think will happen to your holder? Will it be able to meet the criteria? Take a guess!

Then, find out if you were right! Test your prototype by placing the cans in your holder and walking around the room.

During the test, you may find things that work and others that don’t. So, after testing, make sure to ask yourself: How could you improve the prototype?

Then, improve your holder using what you’ve learned. Once you have a new version, test it again to see if your changes worked!

Want More Challenge? Try This!

  • Design a holder that can hold more than six soda cans. See how many cans you can design it to hold!
  • Add another function to your holder. So your holder can hold cans, but what about lunch? What else can you design your holder to do?
  • Learn more about the materials that make up your holder. How could you make it more sustainable? How could it be improved to be better for the environment? What materials could you use?

Once you’ve created a can holder or any type of prototype, you can share it with others. They can help you to think of new ideas and look for ways to make your prototype even better.

And that’s it! You’ve completed a design challenge from the Senior Think Like an Engineer Journey! You’ve learned about the Design Thinking Process and used the steps to engineer a prototype of a soda holder that isn’t harmful to animals.

If you had fun with this design challenge, check out the other activities in the Think Like an Engineer Journey. Or, explore more about engineering and computer science with the Robotics badges. 

Adapted from the Design Squad® Global "Harmless Holder" activity. © 2017 WGBH Educational Foundation. Design Squad is a registered trademark of the WGBH Educational Foundation. and Design Squad Global is a trademark of the WGBH Educational Foundation.

Note: Girls, volunteers and families are encouraged to take the time and space they need to adjust to this period of rapid change and uncertainty. When they’re ready, we’re here to support Senior and Ambassador Girl Scouts to safely take action in their communities—whether it’s helping ensure kids are still getting the nourishment and enrichment they need out of school, responding to the possible ramifications of isolation during social distancing, adapting an existing project to positively impact local communities today, or something else entirely! 


Troop Leaders:  The instructions for all badge steps are available free of charge in your  Girl Scout Volunteer Toolkit.

Girl Scouts at Home activities have been adapted from existing Girl Scout programming and optimized for use at home during a period of social distancing.

Adapted from the Design Squad® Global "Harmless Holder" activity. © 2017 WGBH Educational Foundation. Design Squad is a registered trademark of the WGBH Educational Foundation. Design Squad Global is a trademark of the WGBH Educational Foundation. Contact your troop leader or your local Girl Scout council to become a Girl Scout and learn all the requirements needed to earn the award badge.