The Marshmallow Challenge

The engineering design challenge:

Design a machine that will throw a marshmallow as far as possible. (Optional: design your machine so that it can hit a specified target.)

List of Materials:

• LEGO Education WeDo (or LEGO MINDSTORMS kit)
• Marshmallows
• Chart paper and markers
• Masking tape and marker (to mark the floor)
• Rulers

Engineering Concepts:

• Planning, building, testing, data collection and graphing, iteration

Integrated Concepts:

• Measurement and Data (math)
• Forces (science)

Description:

Students will design a machine that throws a marshmallow as far as possible. (If students meet this requirement, they can work on calibrating their machine to throw the marshmallow a specific distance and hit a target. Or, for example, making their machine consistently throw the marshmallow "5 feet.")

Students will work in groups of 3-4. There will be a Project Manager (for interacting with the teachers), a Materials Manager (for obtaining supplies), a Recorder (for recording plans and worksheets), and a Data Reporter (for graphing results on the chart). Each group will need an identifying name for the classroom graph (I used candybar names, since the challenged used marshmallows.)

Planning: As this is only a two-day activity, and because students are expected to rapidly test and redesign their machine, planning will be very short and informal. Give students 5 minutes to brainstorm a general idea of what shape their design will take, and the essential materials they will need.

Building: After planning time is over, students can begin building. Each group will only be given one marshmallow for testing, so they will need to keep track of it and not let it get lost/squished.

Testing: The testing station in the halloway will be open as soon as building begins. The testing station will have tape strips to mark off feet, and students will have to measure to the nearest inch with rulers. There will also be a starting line that all pieces of the machine must be behind when the machine begins to throw.

Graphing: When students are satisfied with their maximum distance during testing, they can record their distance on the classroom graph, on the row for their group's name. As they continue to revise and test, they can add more data points to the graph.

When time is up, the group with the longest distance wins!

Iteration will be encouraged because:

• The problem is not over-constrained (build "a machine")
• The problem has well-defined boundaries and objective requirements (Length is an objective, testable requirement)
• Students are allowed a role in defining the problem (Students are able to design any kind of machine that will throw the marshmallow. There is a huge opportunity for variation in design.)
• Iteration is explicitly encouraged through the structure of the lesson and classroom (Planning is not extensive, so ideas are not constrained to the students' original designs. Testing is encouraged early and often, and results are recorded publically on the graph to encourage students to improve their design.)
• Testing is encouraged and expected (the designated testing station is open for the entire lesson)

Notes from lesson enactment:

• Students were very motivated by the competitive aspect, but it stayed friendly. I observed students debating on the merits of different designs at the testing station.
• The winning group achieved success after discovering that, if placed on its side, the marshmallow would roll, increasing the distance travelled.
• One group built a car, which didn't strictly meet the challenge specification of "throwing" the marshmallow. I allowed the design out of creativity, and gave it an honorable mention, but still awarded the group with a throwing mechanism the top prize.