Nathaniel Kinsey, Ph.D., assistant professor in the Department of Electrical and Computer Engineering.
Nathaniel Kinsey, Ph.D., assistant professor in the Department of Electrical and Computer Engineering.

Your E-ZPass is not magic

Visual simulations bring the invisible to life to give the big picture — literally — of the physics behind electromagnetics

For electrical engineering majors, electromagnetics isn’t just a challenging class. It’s a rite of passage.

“This is the class that makes or breaks us,” said electrical engineering senior Robert Grey. “You hear a lot about it and it’s known for being really hard. But getting through it is what makes you an electrical engineer.”

What makes electromagnetics such a challenge, even for students who gravitate to electrical engineering?

“Through things like Wi-Fi and cell phone towers, electromagnetic fields are all around us but we can’t see them, feel them or interact with them,” said Nathaniel Kinsey, Ph.D., assistant professor in the Department of Electrical and Computer Engineering. As a result, he said, these phenomena seem like “some sort of black magic wrapped in an enormity of complex math equations.”

So to the novice, Kinsey said, “your E-ZPass seems like magic.” Except that it’s not. “If you could see the fields, if you could see that there is a link coming from the antenna overhead and connecting to your pass, you would see the information being transferred, it would start to make sense,” he said.

But without that visual, students have traditionally had to try to “see” electromagnetics through a combination of advanced math and complex physics, which many are learning and combining for the first time. Thus, Kinsey said, “it’s easy to get stuck in the math and miss the picture of the physics behind what’s happening.”

To restore that missing picture, Kinsey has designed interactive, computer-based simulations that display electromagnetic problems as colorful, 3D images. He and his teaching assistants build these simulations using the COMSOL Multiphysics software, which lets students rotate and scale the electromagnetic fields with which they are working. Students change parameters in these simulations and, voilà, the field can be seen on screen and interacted with like water — or smoke or wind.

“The simulations make fields visible. Students can interact with them, combining thought and motion and creating a sort of muscle memory,” Kinsey said.

Rahnuma Rahman, a Ph.D. student and teaching assistant in Kinsey’s electromagnetics courses, has seen the breakthrough this teaching method brings about.

“Instead of looking at all of the equations first, you’re looking at the result first and working backward to understand the problem,” she said. “Let's say we have two electrons. What is the distance between them? You can change that. How many do you have? You can change those and see the resulting field changing. Students can work out the relations among these parameters and from that can relate it to the equation or theory that they learn in class.”

When students have a strong intuitive grasp of the nature of these fields, Kinsey said, “the math makes sense. It isn’t abstract. In fact, it can be the simplest, most compact way to describe what is happening.”

For Grey, this simulation-based learning has helped him answer some of the longstanding questions that drew him to electrical engineering in the first place. “I wanted a deeper understanding about things like voltage and the physics of electricity for a long time, as early as high school,” he said.

The COMSOL simulations unlocked not only the underlying principles of electromagnetics, but also a new way of thinking about them.

“To solve these problems, I have to do a rudimentary version of what COMSOL Multiphysics is doing at a higher and more complex level,” Grey said. “It has essentially taught me how to think like a computer.”

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