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Battle of the X-Planes

Classroom Activity

To design a backpack that meets multiple needs.

Materials for each group
  • copy of the "Backpack Challenge" student handout (PDF or HTML)
  • copy of the "Designing Your Backpack" student handout (PDF or HTML)
  • copy of the "Material Costs" student handout (PDF or HTML)
  • graph paper
  • ruler
  • variety of student backpacks
  • standard-sized textbooks
  • pens and pencils
  • other materials as specified by students
  1. Tell students they have been hired to be designers for a backpack company. Organize students into groups and distribute a copy of the "Backpack Challenge," "Designing Your Backpack," and "Materials Costs" student handouts and materials to each group.

  2. The backpack students design must include space for two textbooks, one notebook, and pens and pencils. Ask students to specify three additional objects they would like the design to accommodate. Provide a class set of those items for students to measure. Objects might include sneakers, three-ring binder, water bottle, jacket or sweatshirt, cell phone, and keys. Students might also decide to specify design elements, such as comfortable shoulder straps, water-resistant material, or a reflective strip.

  3. Have students first look at existing backpack designs to understand some of the limitations and construction issues. Then have each group design a backpack to meet the needs outlined in the "Backpack Challenge" student handout, determine the amount of material necessary to create their design, and calculate the costs using the "Materials Costs" student handout.

  4. Have students evaluate their initial designs and associated costs and redesign the backpack until they are satisfied with their results.

  5. Upon completing their final design, have groups use any medium to create an advertisement highlighting special features of their backpack, including its dimensions, how the product meets design requirements, additional selling features, materials used, and cost. Note to students that the cost they calculate from the "Materials Costs" student handout is for materials only; actual production would also include labor, marketing, and distribution costs.

  6. Conclude the lesson by comparing final designs and reviewing each group's process with the class. Ask students to discuss which design they think is the best overall and why.

  7. As an extension, have students develop a marketing campaign for the chosen backpack.

Activity Answer

As they complete the challenge, students will likely come to understand that there is no such thing as a perfect design. Trade-offs of one kind or another must be made in order to find an optimal design, one that provides the most desirable results possible given a set of restrictions. Designers are constrained by what actually can be manufactured. Other constraints include price, size, materials available, or environmental concerns. It is quite often the case that the technology is available to create a better, more advanced product, but the need to maintain an affordable price, or limit environmental impact, constrains the design.

There are many possible solutions to the backpack challenge. A successful design will meet all the requirements. Other design features, such as comfort or appearance, might place one backpack in better favor than another. For example, a backpack designed so that all the weight is on one side might be unwieldy and difficult to keep on your back. Additionally, a backpack that has a certain appealing "look" to it might sell better than another that doesn't look as nice but is designed more functionally.

Links and Books


Sweetman, Bill. Joint Strike Fighter: Boeing X-32 vs Lockheed Martin X-35. Osceola, WI: Motorbooks International, 1999.
Covers the competitors' designs and performance features and includes photographs of production lines, test designs in flight, power plants, weaponry, cockpits, and markings.

Web Sites

NOVA's Web Site—Battle of the X-Planes
In this companion Web site to the NOVA program Battle of the X-Planes, which covers the Joint Strike Fighter program, read interviews with the producer and a test pilot, discover the principles of stealth, see what fighter pilots wear to protect themselves, explore what makes planes airborne and the importance of wing design, and more.

Joint Strike Fighter
Serves as the official site of the Joint Strike Fighter, providing a complete background on the development of the Joint Strike Fighter program.

Military Analysis Network
Gives details on which design eventually won the government contract and why.


The "Backpack Challenge" activity aligns with the following National Science Education Standards and Standards for School Mathematics.

Grades 5-8

Science as Inquiry

Science Standard E:
Science and Technology

Abilities of technological design

  • Design a solution or product. Students should make and compare different proposals in the light of the criteria they have selected. They must consider constraints—such as cost, time, trade-offs, and materials needed—and communicate ideas with drawings and simple models.

Understandings about science and technology

  • Perfectly designed solutions do not exist. All technological solutions have trade-offs, such as safety, cost, efficiency, and appearance.

  • Technological designs have constraints.

Math: Measurement

Mathematics Standard 13:

Grades 9-12

Science as Inquiry

Science Standard E:
Science and Technology

Abilities of technological design

  • Propose designs and choose between alternative solutions. Students should demonstrate thoughtful planning for a piece of technology or technique.

Understandings about science and technology

  • Creativity, imagination, and a good knowledge base are all required in the work of science and engineering.

Math: Measurement

Mathematics Standard 13:

Teacher's Guide
Battle of the X-Planes

Video is not required for this activity