The marshmallow challenge is a simple design exercise which shows you the importance of brainstorming and running pilots. Although in this case they participants will design a product (structure), these concept can also be used when (re)designing a service or process. the lessons learned can be applied in your daily work when you have to be creative and innovative.

The goal is easy. You have to build the tallest freestanding structure possible which one Marshmallow on the top while only using the provided materials:

• 20 spaghetti sticks
• 1 meter or 1 yard of tape
• 1 meter or 1 yard of rope
• 1 marshmallow (don't eat it :-) )

The marshmallow challenge is a good team building activity which you can perform if you need to start the design of a new product or service Or if you want them to broaden the knowledge of your team on how to perform a good brainstorm session.

Furthermore, the marshmallow challenge can also be used to teach some fundamentals on practical problem solving.

Rules

you can break up the spaghetti sticks and cut the rope or tape in as many pieces as you want.

You can not cut (or eat) the marshmallow.

You do not have to use all the materials.

The height of the structure is measured from the table surface to the top of the marshmallow. Therefore the marshmallow should be ideally on the top of the structure.

You are not allowed to use other objects such as chairs, laptops, pens, ... The structures has to stand on his own at the end.

Your are not allowed to use other surfaces such as the walls or ceiling.

You have 18 minutes to build the structure. Afterwards you are not allowed to hold on to the structure. If you touch or hold the structure afterwards you will be disqualified.

The winning team is the team with the highest freestanding structure.

Make sure that the rules are always visible for all the teams throughout the complete marshmallow challenge. It allows the participants to check them easily again themselves when they are in doubt. And it give you the time to monitor if the teams are following the rules rather then to explain them over and over again.

Don't forget the most important rule: Have fun!

Preparation

Create groups of 4 to 5 people. 1 table per group. If the people do not know each other well it could be beneficial that you define who will be in which group. For small groups this can be done at hoc, but for larger groups you should do this upfront. You can hang out the different groups on the wall of project them on a screen.

Make certain that there is enough room to move around the table so that each team can move freely without disturbing the other team.

Next you have to prepare the required materials for each team.

For the marshmallow any brand should work as long as it are standard size marshmallow. So don't use jumbo size or mini marshmallows. Make certain that you work with fresh marshmallow. If they are to long exposed to the air they become hard which makes it difficult to pierce them.

Also for the spaghetti sticks all brands should work as long as they have a standard length. Just for your information there are roughly 400 sticks in 500 grams of spaghetti.

The rope and tape are used to put the stick of spaghetti together. For this purpose the rope should be not to thick.

Don't forget to give them a pair of scissors so they can cut the rope and tape easily. Keep it safe!

You should foresee 50 to 70 minutes for the total exercise depending on the number of trainees and the group's culture.

• 5 to 10 minutes to create the group
• 10 minutes to explain the rules
• 18 minutes to do the exercise
• 5 to 10 minutes to measure the results
• 10 to 20 minutes to discuss the results and the lessons learned

Before explaining the rules introducing the marshmallow challenge shortly. Explain to them that they should work as a team. Also, don't forget to mention that afterwards you would like to have a discussion on the results and define some lessons learned. They will be able to use these lessons learned in their future work. But don't tell yet in detail what the lessons learned will be otherwise you will ruin the exercise. In the end, the main goal of the marshmallow challenge is not to have the highest tower but to learn some valuable lessons!

Explain the rules to the participants, make certain that they understand the rules. Repeat them a couple of times so that you are certain that everyone understands them.  Ask if there are any questions before you begin the exercise.

Make sure that the teams can know how much time they have left. If you have a projector, you can show a countdown clock. If you have no projector you can tell the time every minute. Don't forget to shoot out the last minute and count down the last 10 seconds out loud.

Don't forget to foresee a Measuring Tape. You will need it to measure the different structures the teams have built. I find that a retractable measuring tape works the best, but any measurement tape will do the job.

Depending on the group's culture you could provide a small price for the winner. Make certain that the price will not lead to a severe competition because then the fun part will disappear.

3, 2, 1, let's go!

the marshmallow challenge

During the exercise you will see that some teams try to bend the rules in their favor. This is human nature! Make certain that the rules are followed and none of the teams get an unfair advantage.

typically, the teams will use the tape to stick the foundations of the structure to the table. This is allowed. Of course they can also use the tape for other purposes such as sticking the spaghetti sticks together or using it to fixate the marshmallow.

During the build you will maybe see that teams use object to support their structure temporary.  This is allowed. But when the 18 minutes have past the structure has to stand on its own without the support from any object or surface.

Keep in mind that it should be a team building activity and that people should have some fun!

If you see that people get frustrated remind them that it is just a game and the main goal is to learn from it rather than building the largest tower.

Don't forget to walk from table to table to observe how teams tackle the problem:

• How do they come up with a solution?
• How do they organize the brainstorming?
• Do they use iterative design?
• How do they take the decision for the final solution?
• ...

Let the teams know how far the other teams are. this will build some healthy competition. Again make sure that you adapt your communication to the group's culture.

As mentioned, don't forget to shoot out the last minute and count down the last 10 seconds out loud.

10, 9, 8, 7, 6, 5, 4, 3, 2, 1.  The marshmallow challenge is officially finished.

Remind the teams that if they support there structure from now on they will be disqualified! Last minute build structure will tend to fall down and it could be verry tempting to quickly hold on to the structure to prevent it from falling down.  A well build structure will also be a stable structure.

Start measuring the different structures and declare the winner!

You can start discussing the lessons learned after the winner has been declared ,and optionally,  you have awarded the team their price.

Lesson learned

• Running a pilot (prototyping/testing) to validate your concept is import. The marshmallow is quite heavy for the building materials at hand. Teams that spend all the time discussing the ideal design and building it at the end will probably fail. At the other hands, teams that use iterative design, meaning testing concepts and learning from it, will be more successful on average. They will find out quickly that the marshmallow is heavier than they thought.
• Practical problem solving means that you have to go to the place the work is done to gather data and run experiments to further increase your knowledge. This is the only way to validate assumptions. You cannot solve a problem from behind your desk. This is also the case in the marshmallow exercise. You have to build several towers to see what works best, it cannot be done just on paper. By running the experiment the team will quickly discover that it was a false assumption to think that the marshmallow is light.
• Typically teams who use iterative design do not only build a higher tower but are often sooner ready. Illustrating that iterative design will get you the market faster.
• Watch our article on brainstorming to get some lesson learned on how to perform a good brainstorm session.