The Art of Breaking a Bridge

Waldorf graduates understand that their personal experience, a sense experience, is a major piece to appreciating and tying together their education. It is periodically referred to as a three-dimensional kind of imagination.  It’s the experience of recognizing how to learn through observation.

Where it started

The evolution of the Bridge Project, an Upper School staple for the past ten years, is an ideal approach to how the sense experience, in each bridge, has developed and matured since its inception. When the project began, bridges could sustain five or six bricks, according to Marisha Plotnik, an esteemed Physics teacher with 19 years experience at Rudolf Steiner School. Today, the students are building bridges that are supporting weights of over 1,000 pounds.


“What’s really interesting is the building of the bridge,” says Plotnik.  “We have now embedded the bridges in an actual geographical reality, based on the design of an existing bridge – that’s the sense experience.”

Instead of just telling students what dimensions their projects are required to meet, Steiner teachers embed the bridge in a story that requires imagination, mechanical and perspective drawing prior to the modeling of the respective bridge.  All of these elements tie together to create an overlap with a three-dimensional view of civilization.

“I’ve been told by prospective parents, such as a geologist recently, that the modeling and design approach that our students are taking up in their stories is on an entirely different plane,” says Julia Hays, Upper School Area Chair.  “I make prospective students stand on these bridges – their entire weight. The geologist said that he would have greatly benefitted from an education with a multi-dimensional approach in high school.”

Upper School math teacher Dan Marsch introduced the Bridge Project ten years ago. He cut down trees and milled them by hand – creating a substantiality that is much richer.  As each year passed, the expectations altered about the amount of weight a bridge would sustain.  Plotnik went on to stress that the weight bearing is purely for fun.  Records are not maintained, and the projects are not tied to a student’s grade – some students, in fact, choose against building their bridge with weight tolerance in mind.  They simply want to build a beautiful bridge with individualized expectations and goals. Teachers are most focused on the students’ methods of working and their own experience of focusing on goals.

Over the past couple years, students began visiting the bridges in advance of sketching.  They hiked up the East River with the intent of understanding the New York City bridges more.  Architecture teacher Yael Hameiri presented the students with a beautiful series of lectures on both the bridges themselves, and how they were constructed, using different tension and compression.

Hameiri and Plotnik began searching for geographical locations with specific proportions.

“I started looking at topographic maps for bridges that were narrower and taller than bridges that are typically found around New York City,” says Plotnik.  “We took a train up the Hudson River with the 10th grade to the Dia Art Foundation in Beacon, NY.  I found the Popolopen Creek Bridge by NY Route 9W – it’s very high and narrow. Dan and I built a physical representation, which the bridge needed to fit into that landscape.”

The dimensions and the requirements were the same as they were the previous year – 17-inch clear span that an 11-inch boat needs to be able to sail through unimpeded.

So how is it possible for architectural models, built with balsa wood, hold 1,000 pounds?  It’s all in the engineering, states Plotnik.  Wood doesn’t withstand much tension, and it can be snapped easily. But, it does withstand a lot of compression.  An incredibly strong person can push the capacity of the wood to withstand the compression, and it would not break.  It’s simple engineering questions where specific shapes are created that allow the design to work with compression forces as opposed to tension forces.

“I had a class in college called Introduction to Engineering Design where I had a great advantage because none of my teammates knew how to be creative and think outside of the textbook,” said Benjamin Trachtenberg ‘12, a junior at Rensselaer Polytechnic Institute (RPI), who is majoring in Mechanical Engineering (with the intentions of adding Product Design as a double major).  “I was able to come up with an idea that lead the team into building a great project.”

Recognizing the power of the art structure through observation is the paramount first step of the Bridge Project. The students sketch stone arches in Central Park, which is an example of engineer compression. They analyzed the RFK Bridge (formerly Triborough), a suspension bridge, and the Hellgate Bridge, which is a railway.  This offers a feeling for the structure.

In their math class, students discussed the bridges, and followed with vector analysis of the forced diagrams. They pondered the answers for structural questions, such as ‘how are those forces resolved?’ Students developed an appreciation for the effort of increasing the angle of suspension, or the results of doubling compression.  “It’s a trigometric relationship, so it’s not linear, it goes by square powers and trig functions,” says Plotnik.

The Bridge Project has developed significant capacities of the students in a relatively short period of time, and it achieved those capabilities through the personal experiences of each student. The excitement that reached a feverish pitch in the Upper School Assembly Room on June 11 when each bridge was put to the weight test was full of anticipation.  But, more important was the pride and outright respect that was shown to the students who put their hearts and souls into these projects. The Bridge Project will continue measuring in many fascinating ways, but it will always be held with a genuine, heartfelt sense experience that defies the expectations of each student in attendance.