How cold can it get before my pipes burst? How long will this new battery last to power my cell phone? How warm does water need to be to heat my home?
The students who took 3.012 Fundamentals of Materials Science and Engineering learned the answers to these questions and much more during the new and improved 2012 fall semester of the thermodynamics component taught by Jeffrey C. Grossman, MIT’s Carl Richard Soderberg Associate Professor of Power Engineering. Because 3.012 (broken into thermodynamics, taught by Grossman, and structure, taught by Professor Silvija Gradečak of materials science and engineering) is the first required class for undergraduates who have declared materials science and engineering as their major, Grossman wanted to make sure the students came away knowing the basics. But he also wanted to find a way to make learning more fun and memorable to get them excited about what was ahead. So, after teaching the class for three years, Grossman was ready to make it his own by changing things up a bit through what he calls “demo-driven thermo.”
“The idea is that some classes, like basic physics 101, benefit tremendously from a bit of built-in intuition—like the idea of conservation of momentum, throwing a ball into a wall. A lot of what we remember are concepts that feel tangible,” Grossman says. Thermodynamics, on the other hand, can sometimes be very unintuitive. “The idea was to add intuition into the class. To do that, we needed to get stuff into people’s hands. The more you can touch and feel thermodynamics, the more you’re going to connect to the concepts.”
Having received funding from the MIT Energy Initiative through a grant from the S.D. Bechtel, Jr. Foundation, along with support from the Department of Materials Science and Engineering (MSE), Grossman sent his former teaching assistant Kevin Gotrik, graduate student in MSE, out exploring thermodynamic demonstrations to use to enhance the class. Grossman and Gotrik spent the summer of 2012 designing, testing, and retesting demonstrations to illustrate the concepts Grossman would teach in class.
After many experiments—some successful, some unsuccessful—Grossman was ready for the first day of class. At the beginning of that class, and each class that followed, he presented a demonstration and then asked related questions. For example, in one demo, he showed the students a bottle of water that he had cooled to -10°C—but it was still liquid. He then poured it into a bowl. As he poured the water, it turned into ice. He explained that under certain conditions materials can be cooled below their solidification temperature—and the reverse, materials can be heated above their melting temperature. What makes them change from one phase—for example, liquid, solid, or gas—to another?
Grossman then went into a lecture about phase diagrams, explaining how materials change phases. After teaching his planned lesson, he applied the concepts to answer the initial question. Using the “supercooled water” example, Grossman explained that the water was in a phase it didn’t want to be in: It badly wanted to be ice. Hitting the bowl was enough to nucleate the water, enabling it to change from the liquid to the solid phase.
“I think seeing all these hands-on demonstrations, seeing all the cool ways what you’re learning can be applied to things like making motors or causing chemical reactions, is a great way to get the students to connect with the lecture material,” says Sam Shames ’14 of MSE, who experienced the class without the experiments as a student and with them as the teaching assistant for the new-and-improved class.
“I remember from the year before— when I was taking the class—which concepts we got quickly and which were more difficult,” Shames said. “Having experienced that, I could see how having the demos there took some of the more difficult concepts and made them more concrete.”
Beth Murphy ’15 of MSE, who took the class in fall 2012, agrees. “Experiments can be fun, but sometimes it’s hard to see how they back what you’re actually learning. But Professor Grossman did a really good job of tying them together. He brought the science to life.”
Shames’ favorite demo explained how when materials change phases, some of their properties—such as volume—change as well. To demonstrate this concept, Grossman took a steel pipe and held it up. He then hit it with a hammer. Nothing happened. He tried a bigger hammer. Still, nothing happened. Then he took a sledgehammer, created a huge bang, and still the pipe didn’t even crack. Finally, Grossman poured water in the pipe and poured liquid nitrogen over it, freezing the water. Unlike most materials, which contract when going from a liquid to a solid, water expands. The pressure created by the freezing water caused the pipe to burst.
Shames says that all of a sudden something that seemed so abstract “is right in front of you…Something clicks and it all makes sense.”
He says this is “the coolest part” about the demos—not the shock the first time but seeing them the second time, when you understand why it is happening and “make the connection with something that was just an equation on the board.”
Achieving this “clicking moment” strikes at the heart of what Grossman’s “demo-driven thermo” is all about.
“I tell them all, go out and tell people about thermo. Use these demos and make it fun,” Grossman says. “So even in 10 years, when they’re in some spinoff changing the world or whatever, the hope is they’ll have a memory of this and be able to connect it back to the basic concepts. That’s the idea… showing students how they can use thermodynamics to answer questions that come up on the job and in day-to-day life.”
Grossman believes his enhanced class is a perfect example of why residence-based education is still really important in today’s increasingly virtual world.
“Everyone is excited about online learning, and I am too. But what we do so well at MIT—it’s kind of the slogan of the Institute—is that we couple learning with practice, experiment with theory. And I think the power of that in the classroom is tremendous.”
This article appears in the Spring 2013 issue of Energy Futures.