1. Explain to students that they will be designing and building something that can store headphones and keep the wires from getting tangled. This is a product that will be marketed to middle and high school students. Some of the design constraints are that it needs to be small enough to fit in a pocket, it should be lightweight, and it can be made only with the materials provided. (Demonstrate to students how headphones get tangled. Ask them to think of other things that get tangled, like jewelry chains and hands-free devices for cell phones.)

2. Review the engineering design process with the students, describing each of the steps: Define the challenge, research and brainstorm solutions that fit within the given constraints, design and build a solution, test and evaluate the solution, and redesign if necessary. Use the Engineering Design Process Diagram PDF Document, What Is the Design Process? QuickTime Video, and Funny Boat QuickTime Video to emphasize the steps used.

3. Have the class review the Young Inventors Flash Image collection and discuss the challenge each student addressed with his or her invention. This can be done as a class or in small groups. Make sure that the class is aware of the ages of the students who designed these inventions.

4. Briefly review the challenge and constraints with the students, making sure to identify the parts of the design process with which they are associated. (Note: This step is to reinforce where the students are in the process before they begin the next phase.)

5. Let students know that they are starting the brainstorming and research component of the design process. Have them discuss options for how to keep headphones from getting tangled. Ask students if they can think of any examples of similar items. Show the Easy-Fit Design QuickTime Video to emphasize the research and brainstorming steps of the design process.

6. Divide the class into groups of two to three students, and have them share ideas with each other about what they think might work. Tell them to sketch all of their proposed ideas in their science/technology notebooks. Reinforce the notion that there are no bad ideas when brainstorming. What existing products or models have they seen that might be good for storing headphones?

7. After they have brainstormed ideas, have the groups list the important features that they think their storage device should have. For example, what size should it be? How easy should it be to access? Should it hold more than one set of headphones? Let students know what materials will be available to them, so that they can keep the design constraints in mind while developing their solutions.

8. With the students still in their groups, ask them to draw their proposed solution to the design challenge. Their drawings should be done on the same page (or on a new sheet if the previous one is full) that has the challenge, brainstorming, and design constraints information. Make sure that they include diagrams that show all the parts of their holder and/or how it will work.

9. Have each group choose the design that they think would be the most promising solution to build.

10. As a class, review the selected designs, discussing which ones students think will work the best.

11. Have each group of students build a tangle-free headphone holder. Each group should select one design that was drawn by one of its members and construct it together. While building their design, students can use their own headphones, if available, or two pieces of string (knotted together along half the length, and loose for the remainder, forming a "Y") to simulate headphones. If they use string, tell them to keep in mind that real headphones have earpieces. Provide students with access to the assortment of construction materials. Tell them to use masking tape to hold the construction together. Show the How Do You Keep Lemonade Cool? QuickTime Video to prompt a discussion about which materials are best to use and why.

12. Have students test their tangle-free headphone holders. Tell them to consider the following: How well did their invention meet the original design constraints? What needs improvement? How are students recording the success or failure of the tests? Optional: Have groups exchange their prototypes with each other, so that each tangle-free headphone holder is tested by someone other than its designers. Student groups can share instructions about the use of their prototypes as needed.

13. Show the Simple Solutions QuickTime Video and talk about how Amy Smith's design changed drastically throughout the design process — from a large device with aluminum to small balls with no aluminum.

14. Explain that almost everything that is built needs to be modified (redesigned) to make it an even better product. Have the students go through a redesign process with the models that they made. The "improved" versions will need to be tested against the same design constraints that were used on the first model, and the results recorded in the same format — ideally on the same page.

15. Ask the students to discuss the following points:

1. How did their designs change?
2. Why do they think their designs are better as a result?
3. Did they have a hard time letting go of their initial ideas, as Amy Smith did?