Using a PEM Fuel Cell as the primary power source, student teams design, build, and test prototype vehicles which they must then present to an audience. The AWIM Fuel Cells Challenge requires students to explore physical science concepts such as force, friction and energy transformations as well as environmental concepts such as green design, and incorporates mathematics concepts as student teams collect, analyze and display data.
The Fuel Cell Challenge has been designed to supplement the curriculum of a middle school science teacher. Like all AWIM challenges, the Fuel Cell Challenge will join together teachers, students, and industry volunteers in an exploration of physical science while addressing essential mathematic and scientific concepts and skills.
In the Fuel Cell Challenge, students receive a letter from a fictitious toy company, Green Design Toys (GDT). Green Design Toys is interested in receiving new designs for toys that are environmentally friendly and are powered with alternative power sources and fuels. This letter asks students to work in teams to design a vehicle that can meet specific performance goals. Students are asked to keep a design log in which they record the results of experiments, design sketches of their vehicles, and performance data. The program culminates in student presentations of their working models and a discussion of the design teams' efforts to address the challenge.
This challenge presents students with the opportunity to investigate a new and developing technology; the fuel cell. Over the course of the curriculum, a variety of activities introduce students to the development and use of fuel cells, types of fuel cells, and hands-on experiments with a PEM (proton exchange membrane) fuel cell to produce electricity to power an electric motor.
Lesson 1: Reading and Evaluating the Request For Proposal (45 min)—Students receive a Request For Proposal (RFP) from the director of new product development at Green Design Toys (GDT), a fictitious toy company. The RFP explains that GDT is looking for new designs of a toy to add to their current product line and is inviting design teams to submit proposals and prototypes of their ideas. Students will carefully read the RFP to determine what is expected of the design teams and what is needed to meet the challenge. They use the Evaluating the RFP Log Sheet to begin analyzing what the RFP is asking them to do.
A volunteer engineer visits the class to talk to students about how engineers work when they design things. The volunteer's conversation with the students focuses on the engineering design experience, the purpose of an RFP, working in design teams, and using design logs to keep careful records of their work. Students can use this opportunity to ask the volunteer questions about the RFP.
Lesson 2: Team Formation and Recordkeeping (45 min)—Students are divided into design teams. The class discusses how to work in teams, and the roles they will take in their teams. Students then work in their design teams to design a team name, logo, and slogan.
In this unit student design teams will record their work in Design Logs. This activity introduces students to the importance of keeping a Design Log, and ways they can use their Design Logs to keep a record of their work and to reflect on their designs.
The activities in the unit suggest specific ways the Design Logs can be used. You may want to suggest to students other ways they can use the Design Logs. For example, students will need to use data recorded in their Design Logs to document the development of their vehicle designs as part of their final presentations. Students can also use the Design Logs to record questions they want to pose to other students, the teacher, the volunteer engineer, or others. Finally, you can use students' Design Log entries to assess their understanding of content, design process, and writing skills.
Lesson 3: Looking at Powered Vehicles (45 min)—In this activity, students are introduced to the basic components of powered vehicles, and the dynamics of vehicle operation in a context that will be familiar to most of them: the automobile. They will examine the dynamic forces acting on an automobile. They connect their experience with automobiles to the design of the fuel cell-powered toy requested by Green Design Toys. In addition, students will identify the functions performed by the major components of the automobile and later will relate these to the fuel cell toy challenge.
Lesson 4: What We Know About Fuel Cells (45 min)—As a challenge pre-test, each student is given a diagram of a PEM (Proton Exchange Membrane) fuel cell with a word bank and asked to label the parts of the fuel cell. After viewing some animations of how a PEM fuel cell works, design teams meet to share their thinking and work cooperatively to complete the labeling of a new diagram of a fuel cell. Teams then write a description of how the PEM fuel cell works, describing the paths that hydrogen electrons and protons take through the cell, and the results. Design teams then use a PEM fuel cell to make, collect, and use hydrogen as an energy source.
Beginning with this activity, students investigate several types of energy transfers between the following energy forms: chemical, mechanical, and electrical. In each of these activities students working in teams of four students will record each energy transfer in their design log.
Lesson 5: Chemistry of Electrolysis (45 min)—Students are introduced to electrolysis as a chemical process by which water molecules are decomposed into molecules of hydrogen gas and oxygen gas. They use a PEM (proton exchange membrane) fuel cell as an electrolyser to produce the gases from water.
Lesson 6: Using the Fuel Cell to Produce Power (45 min)—In this activity students use a PEM fuel cell in the electrolyser mode to produce hydrogen gas. This hydrogen gas is used in the fuel cell mode to produce electrical power that is used to power an electric motor.
Lesson 7: Powering an Electric Motor and Gearbox (45 min)—In this activity, students use the electrical energy from the PEM fuel cell to power an electric motor and gearbox to lift a weight. They investigate the process of turning electrical energy into mechanical energy and determine the amount of work produced by the motor.
Lesson 8: Looking at Green Design (45 min)—In this activity students investigate and apply some of the principles of Green Design. Students investigate use of renewable fuels and use of green materials.
Students evaluate the use of PEM fuel cells and an electric motor as the engine for the toy. They compare the merits of this combination with other possible engines and energy sources. Then students compare various materials to determine how difficult it is to reuse, recycle, renew, or dispose of the materials at the end of the life of the toy. Later students may use the results of the materials study to decide which materials they might use to build their toy.
Lesson 9: Writing the Design Brief (90 min)—In this activity, student design teams write a design brief containing design specifications that outline the characteristics of the toy they plan to design for GDT. The design specifications include a description of the type of toy (race car, truck, tractor, off-road vehicle), the appearance of the toy, and the desired performance of the toy (fast, carry a load, or travel over a long distance).
Design teams meet and review the lists they made in activities they experienced in the Set Goals and Build Knowledge phases. Students integrate and apply the understanding they have gained in these phases to create a design that will meet the challenge posed in the RFP by GDT.
Students use the information and understanding from the Build Knowledge activities to design a chassis for the toy. They present their drawings to the class.
Lesson 10: Building and Testing the Prototype (90 min)—In this activity, design teams build a prototype based on the design drawings they made in the Writing the Design Brief activity. Teams carry out performance testing of their prototypes to see how well they meet their own performance specifications. They record results of each test and report the results as data in written, numeric, and graphical form when appropriate.
The design teams interpret the data produced by their tests to see if their vehicles meet the performance criteria. They begin to troubleshoot their designs to isolate factors that degrade performance and, if needed, redesign their prototype.
Lesson 11: Assembling, Testing, and Adjusting the Final Design (90 min)—Students have designed, tested, and redesigned their prototypes so that they meet the performance specifications they wrote in the Writing the Design Brief activity.
Lesson 12: Present (45 min)—Preparations for the final presentation can be overwhelming and hectic. As the final day approaches students will rush to finish their prototypes, diagrams, speeches, and related work. In the meantime, the teachers will need to begin advance preparation for the culminating event.