Spaghetti, Marshmallows, and Earthquake Preparedness

This project works great for a middle school-aged audience but could easily be tailored to elementary-aged students. I used it with both my seventh-grade and sixth-grade classes. The lesson takes approximately 55 minutes to complete but could benefit from an additional 30 - 60 minutes of time reviewing what was learned and how new ideas could improve the results.

February break was just around the corner and we had planned on watching a pretty heavyweight video about the 2010 earthquake in Haiti. One of our past students, Britney Gengel, was tragically killed in the earthquake while she was helping with the orphanages in Haiti. Her family did a truly amazing thing and honored their daughter in the construction of a beautiful orphanage that houses sixty-six children while they developed the Be Like Brit foundation to help those in need in Haiti. The orphanage is built to withstand a 9.0 earthquake, which are the same standards used in San Fransisco. Like I said, the video really does give you some heartache, but the message and inspiration that comes from it is truly remarkable. I didn't want my science class to just end on a discussion but to also make some connections to the science and engineering I teach in my class. I decided that we would do a lab on the following day (Friday before February break) that would help connect engineering design to natural disasters such as earthquakes. It's a bit of a new take on a classic lesson; build a structure out of spaghetti and marshmallows (or gum drops), but in this case I adapted to the idea of building an earthquake resistant structure with certain constraints. Since many earthquakes result in tsunamis and there are often storm surges that accompany hurricanes the structure had to have a living space at the top that would keep it out of flooding waters. All the while the structure had to resist "earthquake-like" vibrations and movements created by a vortex mixer I have in my classroom. I tell my students that they are our future engineers, builders, architects, designers, humanitarians, and citizens. They have the ability to do so much good for our world and science is just one avenue they might take to get there.

I want to share this easy lesson with you and encourage you to take a similar approach to connecting the engineering design process to a real-world scenario.

Spaghetti

Mini-marshmallows

Plastic containers with lids (I used cat cookie containers from Trader Joe's)

Vortex Mixing Machine

Gravel / Aquarium Rocks

Timer

Metric Rulers

I have some fantastic parents in my town that have been unbelievably helpful with materials over the years. I sent out a quick email to all of them the night before the project requesting spaghetti and received 30 boxes worth! I had mini-marshmallows from a previous catapult project we did at the start of the school year... all from parent donations again (it never hurts to ask).

We went through approximately one box of spaghetti and a half bag of marshmallows per class for this project (groups of 2 and about 8 to 12 groups). I also used dixie cups to distribute the marshmallows and keep things somewhat even but I definitely did not count out marshmallows and spaghetti sticks.

One of my student's parents worked in a lab that was replacing damaged or antiquated equipment who incidentally offered up the equipment to me. Along with a centrifuge, a nice hotplate, and a magnetic stirrer, I received a couple of vortex mixers. Usually you use a vortex mixer to mix up liquids or dissolvable solids in a liquid inside of test vials. Basically, you push down on a heavy piece of rubber that initiates a big heavy-duty motor inducing a vibration into the vial. In this case I used the periodic movement of the mixer to represent (to some degree) the movement of an earthquake. Using a plastic cat cookie (for people) container I cut a hold to fit tightly over the rubber center of the vortex mixer. I then cut another container around the rim so it was shorter and would fit neatly into the previous container. This shortened container was filled up partially with gravel until I got the right intensity of shaking figured out. I did this with a couple of test structures my homeroom kids made for me. They build the structures directly on top of the cat cookie lids so that they could snap right onto the container attached to the mixer. Let's just say we went through a lot of gingersnaps, cat cookies, and animal crackers from Trader Joe's back when our own kids were really young so we had a horde of stored up containers that I have been using for labs up the wazoo over the past eight years.

You want the mixer to not vibrate the crud out of the structure but to kind of whip it side to side and then vibrate a bit (more similar to some earthquake movement). You can see this in the video.

Any engineering process has specific constraints that need to be considered. In this case we used some of the ideas presented from the video and based upon the specifications that the Gengel's used to build the small hurricane proof homes for the citizens of Haiti. We added a couple of elements to the design to make the structure both flood and earthquake resistant. This translated to the students designing a structure that had a base between 8 and 10 cm wide (no more than 100 sq cm), a central tower that was between 25 and 30 cm tall, and finally a flood escape area that is at least 6cm x 6cm (36 sq cm) in size. The living space is well out of the reach of flood waters if there was an ensuing tsunami after an earthquake or a hurricane was to strike the area and the entire structure needs to be able to withstand at least 1 minute of earthquake movement using the vortex mixer.

Once my students are in groups of two and three students per group I distribute the materials to them. Each group gets one of the lids to the cat cookie containers to build their structure on, a handful of spaghetti, and a dixie cupful of mini-marshmallows to build their structure. Some groups decided to sketch out the initial designs prior to building, other groups decided to go right to the building process. Many groups figured out pretty quickly that the triangle is the optimal geometric shape to use for both support and flexibility but the way they used the shape was really impressive. I loved all of the ideas and variations each group came up with, and without much instruction on structural design.

The final step with this project is the best part... testing! I use a stop watch to test how long the structure survives the earthquake movement created by the vortex mixer. The goal is for the structure to survive for one minute with little to no structural damage. This is after I have measured the structure to make sure it fits within the constraints given at the onset of the project. If the structure fails during testing I give them a few more sticks of spaghetti if they need it and a few more marshmallows... and occasionally a few tips to help them (i.e. use the stickiness of the marshmallows to help anchor it to the plastic lid). We really had some fantastic successes with the final structures created and the best part is that it took only a single class period to complete the activity. With a couple of class periods or at least 1-1/2 class periods you could really spend some time reviewing the best structures and what made them work so well. I was able to tie in the locations of tectonic plates relative to Haiti, and why it is so important to have engineers and other scientists involved with civilian-based structures.