Grade Level: Middle school; also scalable for elementary and high school
Time Required: 11 hours (wild guess!)
Subject Areas: Problem Solving
Maker Challenge RecapPeople using crutches have their hands occupied, which makes it difficult to carry books and other items they want to have handy. Student teams are challenged to design assistive devices that modify crutches to help people carry things such as books and school supplies. Given a list of constraints, including a device weight limit and minimum load capacity, groups brainstorm ideas and then make detailed plans for their best solutions. They create prototypes and then test for functionality by loading them and using them, making improvements with each iteration. At a concluding design expo, teams present their concepts and demonstrate their final prototype devices.
Maker Materials & Supplies
This open-ended design project requires the use of a general fabrication shop or, at a minimum, an assortment of hand and power tools to support students’ designs and material choices.
- a wide variety of construction and fastener materials for device fabrication, such as woods, plastics, metals, cardboard, foam core board, fabric, string, rope, nails, screws, nuts and bolts, staples, grommets, clamps, needles and thread, Velcro, zip ties
- an assortment of fabrication tools to work with the materials, such as tape measures, scissors, duct tape, adhesives, twine, hammers, screwdrivers, drill/bits, sewing machine, hand/power saws
- a few pairs of crutches, one per group is ideal
- scale, for measuring weight up to ~5 pounds
- depending on the tools used, ear and eye protection
- computers with Internet access, for research
Note: To scale down for elementary-level students, have them create simple devices designed to hold small, lightweight objects using the most basic materials such as cardboard and tape.
Worksheets and AttachmentsVisit [ ] to print or download.
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Have you ever had an injury that required you to use crutches for a few days, or maybe even longer? What was it like to use crutches? Even if you have not used crutches yourself, you have probably seen or known someone who has used them.
Living a normal life with an injury is important, because life does not stop when you get hurt. So imagine that you need to use crutches during the school year. You would need to figure out a way to get around on your crutches all day—to and from school and from class to class—using both arms and hands to manipulate the crutches while also carrying anything you need for the day. What might your needs for your school day be? Perhaps school supplies, keys, cell phone and your lunch! (Adjust this list to make it age-appropriate for your students.)
Another consideration is that many schools do not permit backpacks in classrooms. So how would you carry these supplies if your hands are not free and a backpack may not be used? It means that you need a device to assist you when carrying to class the things you need each day.
To start, let’s clearly state our engineering design challenge: To design a device to enable a person on crutches to carry books and small objects. As with all engineering projects, we must first understand any design requirements and limitations. You might want to write these down in your design journal. For this challenge, your device must be safe to use, weigh less than 2 pounds (~1 kg), be able to carry a minimum of 4 pounds (~2 kg), attach to an individual or pair of crutches, and be completed in three weeks. Now let’s get into teams and start brainstorming ideas to solve this problem.
Realize that the project constraints for weight and safety naturally serve to minimize the size and amount of materials necessary for the activity, so adjust the constraints as makes sense for your situation.
Divide the class into engineering teams of two or three students each.
Suggest that groups conduct research to aid in their understanding of the problem. Prompts: What is a disability? How do disabilities affect humans? Define “assist.” What is an assistive device? (Assistive devices help persons with disabilities to perform many activities of daily living or other activities that they would normally be unable to do.) What are some examples of assistive devices or technologies? (Examples: Eyeglasses, contact lenses, wheelchairs, canes, walkers, hearing aids, replacement limbs, Lasik eye surgery.) How do assistive devices help people? Define “custom made.” Why are some things custom made?
During brainstorming, remind students to make no final decisions right away. Brainstorming is the time for groups to explore and build off ideas contributed by every team member, discuss the pros and cons of functionality and materials, and then agree as a team on a final “best” design solution that meets all the constraints.
Suggest that groups create detailed drawings of their devices (perhaps at half-scale) that include descriptions such as dimensions, materials and fasteners.
- Prompt students to identify the physical properties they want in the materials they use to make their devices, perhaps: rigid, durable, waterproof, cleanable, hard, lightweight, flexible, expandable, inexpensive, padded, insulated, smooth, soft, strong, lockable.
- Then figure out what materials have the desired properties to support the purpose of the device and the conditions it will encounter.
- Remind students to be aware of the weight and load constraints in their design and material choices.
Work with the student groups to review/approve designs as they develop. Encourage students to weigh components as they go to make sure they meet the weight constraint.
Remind students that the purpose of prototype is as a model that can be tested to see if the design functions as intended, and that you can learn a lot from failures.
Remind students that the engineering design process is cyclical and may begin at, and return to, any step. Every time a prototype is tested, evaluated and then redesigned to make improvements we call it a design iteration.
Remind students to take notes to document their tests, results, observations and evaluations, so they learn from every iteration.
Guide students to think about what sorts of tests and measurements to conduct in order to evaluate and evolve the prototype design. Prompts: How much does the device weigh? How much weight can the device hold? Once loaded with 5 pounds, how well does it work? Does the crutch hold the device securely with the chosen attachment method? Are the components strong enough to prevent the device from swinging during use? Does the device location on the crutch create any problems during use?
To conclude, hold a class event such as a “design expo” or “engineering night” with invited families and other classes. Have teams present their design concepts and demonstrate the use of their carrying devices in loaded capacity. Check to see how successful the devices are in meeting the design constraints. Observe the device in use to judge its effectiveness and safety. Notice if any devices provide bonus features and benefits.
To further the analysis, have groups contribute their device weights and maximum holding weights to compile a table of class data. Then create a graph of device weight vs. maximum weight capacities. As a class, discuss the trade-offs that are made for each type of device. For example, a lighter device is easier to carry around but cannot hold as much weight, whereas a heavier device can carry more weight but is not as easy to carry on crutches.
Make the challenge more difficult by having students create their design drawings using a 3D modeling program such as Google SketchUp; add a materials budget or cost limitation in addition to safety, weight, load and time constraints; and/or make available a machine shop and scale up the project materials and prototype quality expectations.
ContributorsDenise W. Carlson
Copyright© 2017 by Regents of the University of Colorado
Supporting ProgramIntegrated Teaching and Learning Program, College of Engineering, University of Colorado Boulder
This maker challenge was inspired by the Design a Carrying Device for People Using Crutches activity that was created by Worcester Polytechnic Institute in collaboration with the Worcester Public Schools.
Last modified: June 17, 2019