Guided Discovery Labs Help Students Cement Engineering Intuition

There’s an old adage that one of the best ways to reinforce your own understanding of a topic is to teach it to somebody else. But there’s another, less common method for cementing knowledge into your brain—discovering it yourself.

That’s the general idea behind the teaching approach being taken by Michela Geri, assistant professor in Thomas Lord Department of Mechanical Engineering and Materials Science, in her session of EGR 201: Mechanics of Solids.

“The most common method of teaching fundamental concepts in college is for a professor to derive equations for the class on a chalkboard,” said Geri, who has been teaching a session of the class since she joined Duke in January 2024. “But I’m trying a different approach, where students try to discover the concepts on their own as if they were the first people to think about them.”

EGR 201 is a fundamental class that the majority of Duke Engineering students take. It focuses on statics, which is the understanding of how structures can stay upright and supported without moving, combined with concepts of dynamics and strength of materials to understand how an object responds to stresses and strains. These topics encompass basic concepts of mechanics, solids, fluids and thermodynamics that students will need regardless of what major they move forward into.

If this all sounds like a lot to cover, that’s because it is: EGR 201 includes material that used to be taught in two separate classes. It’s also challenging, Geri said, to keep all of the students engaged throughout the semester, which is part of the reason why she turned to “guided discovery labs.”

“When students get to this class, they already have the classical ability to conduct measurements and plug them into equations they’re given,” Geri said. “While that is an important skill, it doesn’t always bring a high level of intuition about what the concepts and equations actually mean. In these new types of labs, I tell them they’re like the first people discovering a concept, except they don’t have 100 years to do it, hence they are guided in the discovery process.”

For example, Geri has the students use silly putty to explore the physics of shear stresses and strains, rubber strips to investigate the mechanics of tension and axial strain, and pool noodles to probe the deformation of objects placed under torsion. With these various objects in hand, students are challenged to hypothesize how they will deform under the various loads applied to them and develop a simple model for it. Only after they have a prediction do they go ahead and observe what happens in reality, compare their model to the observations and develop the final theory themselves.

“All of us have our own intuition about what will happen, but sometimes real life is more complicated, or simpler,” said Srinath Iyer, a first-year student in Geri’s section this semester. “The discovery labs are a good way to solidify the concepts and not just learn the equations.”

“When we started learning about torsion, in my mind it was just spinning an object, so you’d probably get a larger angle of twist at the ends where the force was being applied and at its greatest,” said Maddox Hussar, who is also a student in Geri’s session this semester. “That turned out to be all wrong. It’s actually a linear relationship.”

Discovering that preconceived assumptions were incorrect, Geri said, is part of what makes her approach so powerful. Students who get into Duke are typically very high-performing and are used to getting everything right from the start.

The discovery labs give them a chance to fail without any serious negative consequences. Developing hypothesis, testing them and learning from observations is an intrinsic process of any eventually successful engineering endeavor.

“All students will eventually be asked to design something or explore a new concept as an engineer where they don’t know the solution—nobody does,” said Geri. “They need to be able to tackle failure before reaching their end goal.”

Another aspect of discovery labs that Geri touts is the physical intuition that comes from students having explored these concepts with their own hands. These topics can be very heavy on the mathematics required, even if the results are relatively straightforward. Going through all the algebra and calculus can cause students to lose touch with the physical concepts being taught.

“When we learned about tension, we had a rubber strip a couple of feet long with some parts that were thinner and some that were thicker,” said Avrick Altmann, another first-year student in Geri’s session this semester. “It also had colored markings so that we could see exactly how different parts were affected, which gave me a good understanding of why stretching is linear at its core.”

“Rather than just memorizing equations, I got a much more intuitive understanding of how the forces and kinematics actually work,” Hussar added. “And that’s much more useful to me because I’ll eventually forget the equations of how a beam bends under load, but that intuition will stay a lot longer.”

For now, Geri is the only EGR 201 teacher who is using this approach, which she learned as an instructor at the Massachusetts Institute of Technology while working with Profssor Ely Sachs, who has been a champion of inductive learning throughout his career. Being introduced to guided discovery labs, Geri said, deeply changed her perspective on teaching. Because the class is so fundamental and most students take it, there are many sessions led by faculty from all four departments, and each faculty member brings their own approach to teaching the material. But she hopes others will consider using it for their own sessions in the future.

“Some students get it right from the start, and I’m very happy for them,” Geri said. “But some struggle for a bit before a light turns on in their eyes and they understand the concept. Those are the best moments for me and where I think I can make an impact.”