Marshmallow Challenge

Purpose

The Marshmallow Challenge is a design-thinking exercise where small teams build the tallest freestanding structure possible using spaghetti, tape, string, and a marshmallow that must sit on top. It reveals assumptions about prototyping, iteration, and collaboration. Teams that prototype early and iterate consistently outperform those that plan extensively and build once — making it a powerful lesson in agile thinking.

At a glance

• Group size: 8–40 participants (teams of 4)
• Duration: 30 minutes
• Difficulty: Beginner
• Facilitation style: Timed challenge with debrief
• Setting: Indoors; tables required

How to run

1. Setup (3 min): Divide into teams of 4. Distribute identical kits: 20 sticks of spaghetti, 1 metre of tape, 1 metre of string, 1 marshmallow.
2. Explain rules (2 min): You have 18 minutes to build the tallest freestanding structure with the marshmallow on top. The structure must stand on its own. You may break the spaghetti, cut the tape and string, but the marshmallow must be whole and on top.
3. Build phase (18 min): Start the timer. Give time warnings at 10, 5, and 1 minute.
4. Measure (2 min): Measure surviving structures from table to marshmallow top.
5. Debrief (5 min): Share Tom Wujec's TED Talk findings. Ask: When did you place the marshmallow? What assumptions did you make? How did your team make decisions?

Materials needed

• 20 sticks of dry spaghetti per team
• 1 metre of masking tape per team
• 1 metre of string per team
• 1 marshmallow per team
• Measuring tape
• Timer

Pitfalls & common mistakes

• Not testing the marshmallow early: The number one failure mode. Teams that wait until the last minute to place the marshmallow watch their structure collapse.
• Unequal kits: Ensure every team has identical materials.
• Skipping the debrief: The magic is in connecting the experience to real-world project behaviour.
• Teams of 2 or 6: Four is the sweet spot. Two lacks complexity; six leads to passengers.

Inclusion & accessibility

• Provide tables at standing and seated heights if wheelchair users are present.
• This exercise works well across language barriers as it is primarily hands-on.
• Assign roles (builder, architect, time-keeper) to ensure everyone contributes.

Variations

• Marshmallow Challenge 2.0: After the first round, give teams 5 minutes to plan a second attempt with a fresh kit. Compare results.
• Blind Marshmallow Challenge: One team member is blindfolded and builds while others give verbal instructions only.
• Budget version: Replace spaghetti with newspaper rolls and tape for a larger-scale build.

When NOT to use this

• When teams are under real project deadline stress — adding a competitive time-pressure game may increase anxiety rather than teach.
• With groups that have strong competitive dynamics that could turn toxic during a ranking exercise.

Source & further reading

• Wujec, T. (2010). Build a Tower, Build a Team. TED Talk.
• marshmallowchallenge.com — official resource with data from thousands of sessions.