## What it takes to become an engineer

Ideas more or less related to teaching and learning physics at Luther College.

J-term is a unique time in Luther's academic schedule. This J-term I taught one of Luther's engineering courses called "Statics".

So you may be thinking, what the heck is "Statics"? Do you guys study static electricity? Is that the same thing as probability? Actually, Statics isn't about electricity and it isn't the same thing as statistics. Statics is the study of structures that do not move: meaning they are static. In physics and engineering we call this static equilibrium. So essentially the eleven students in this course studied how to keep a bridge from falling down.

The best part of the J-term class was the sense of community that was built between the students in this class. The students had to work hard in order to minimize careless errors that they made on their homework. Just like practicing engineers, the students could reduce the number of mistakes by working collaboratively with others.

The capstone project for the Statics course was a bridge building project. No, this isn't the same thing as the popsicle stick bridges that you built in high school. These pre-engineering students need to be much more precise in their work. Instead of trying to build a bridge that could hold as much weight as possible, their goal was to build a bridge for which they could accurately predict its strength. They also had to predict exactly where the bridge's breaking point would be.

Doing this kind of accurate prediction is hard. It took the entire J-term to get the students up to speed on the basic techniques of structural analysis.

In order to predict the failure of their bridges, they needed to understand the strength of the balsa wood they would use and the strength of the screw joints they would construct. We had the opportunity to use strength testing equipment at a local company, DECO.

Even so, it was possible to build a bridge that could not be analyzed. One group built a bridge that was referred to as a "beauty". Jayden and Sam (seen below) were two members in the group that built this bridge.

While their bridge was beautiful, it was too complicated to analyze. So they decided to save their Beauty Bridge from destruction, and built a second bridge which they could analyze properly.

The students tested their bridges the last week of J-term. They loaded their bridges slowly and hoped their predictions matched the results.

Notice that the bridge in the picture above has the failure locations are marked in red. Jesse's group also drew arrows on the bridge structure. Those arrows show whether the wood members of the bridge were in tension or compression during loading.

Some bridges could hold more than others.

The students discovered that their bridges didn't always fail they way they predicted. A couple bridges broke with the two halves of the bridge splitting apart. You can see in the image below that Rudie and Madeline are each holding one half of their broken bridge.

I have to admit that it was a bit sad to see those bridges destroyed. Fortunately the destruction process was a lot of fun.

My hope is that through this J-term course my students learned what it takes to become an engineer. Engineers know how to work collaboratively with others to make great designs and to minimize design flaws. Engineers need to be detail-oriented and know science principles well. Engineers test materials, built multiple prototypes, and test their predictions. And have fun along the way.