October 07, 2010

 

LEWISBURG, Pa. — Margot Vigeant, associate dean of engineering and associate professor of chemical engineering, talks about new approaches to teaching engineering, learning from misconceptions and how students help teachers teach through the "Gizmo Expo."

Q: Your research looks at conceptual learning in engineering. Can you tell us about your work in this area and why it's important?

A: Conceptual learning is distinct from learning the equations or learning definitions. I think of concepts as, "What people say if you take away their calculator." For example, in the field of physics: You've got a ball on the end of a string and you're whipping it around like it's a slingshot and you let go. After studying physics, people can do the math and predict where the ball will end up. That comes out right. But if you ask them, "What does the ball do after you let go?" a large fraction of people say, "Oh, it keeps spinning," instead of going out straight, which is what it really does.

That's an example of a distinction between the arithmetic, the equations and the numbers — stuff you can memorize — and a concept. Learning concepts is important for a couple of reasons. One, we want to make sure that we are graduating students who can accurately discuss what it is they do with colleagues, the people who they meet on the street and, even, with other engineers.

Two, particularly for thermodynamics, which is the study of energy conversion (Vigeant's area of expertise), it's important because one of the most pressing issues facing humanity is energy: How do we get energy and how can we effectively use the energy sources we have without creating a lot of waste. People really want 100 percent efficiency to be possible. People really want to take all of the chemical energy that is captured in a gallon of gasoline and make that all go into making the car move.

But if society has engineers who say, "Oh, yes, let's try that, let's just keep tweaking that and it will get better," without realizing that there are, in fact, fundamental limits that we are stuck with, we've wasted a lot of time and we've wasted a lot of money and we've fooled a lot of people and we haven't spent our time productively.

Q: Does this research involve others, and what are you discovering?

A: I'm working on this with Professor Mike Prince, who is also in chemical engineering - his area for this particular research is heat transfer, which is related — and also Professor Katharyn Nottis in the education department. She brings in a really valuable component from the educational background and also our data analysis — how you draw conclusions when what you're studying is learning, as opposed to studying chemicals, which is what I was more used to.

There are two parts to this: One is we have worked on a tool to be able to measure what people understand conceptually in the first place. We now have a multiple-choice test that captures this, and what we've found is that, nationally, engineers are walking out of classrooms still scoring about 60 percent. Their conceptual understanding improves after courses (it starts around 50 percent), but nowhere near as much as we'd like.

The second part of our work is in creating materials that faculty can use to repair their students misconceptions. It turns out that one of the most effective ways to change someone's concepts, their pre-existing misconceptions, is by having them experience their misconception being wrong and the correct conception being correct. This is the situation our "inquiry-based activities" seek to create. We are still in the process of testing these activities, but the current data are quite promising. Students show a significant positive change in their scores when activities are combined with their coursework.

Q: What is an example of a misconception in engineering?

A: I'm after several concepts that are very important for chemical engineering students to understand in thermodynamics. One of them is the misconception that there aren't limits placed by the laws of physics on how efficient an engine can get, that is, energy in versus work out, especially if you're talking about the kind of engine that runs cars or runs power plants, what we call a heat engine. Those limits are dependent on the temperatures that you're using. So, if you could have really, really high-temperature steam or such a high temperature that you don't even have steam anymore, or sending something like (the temperature) from the inside of a star, you could get something with a very, very high-efficiency. Except that it's very hard to make an actual machine that can work like that.

When you're stuck in practical situations, you end up trapped with intrinsic efficiency that might reach maybe 60 percent. That's not a happy number. People don't like that. "We're Americans, darn it, and we can always make it better." So my big problem is getting people to work within these limits and get the math that gives us those limits into their thinking as they move forward.

The activity designed to repair this misconception is an engine simulation. As the students work with it, they get lots of feedback on how the plant works, if the temperatures they are using are realistic, that sort of thing. And they can directly experience that the high efficiencies, the ones they really want, only come from unrealistic situations, and that 100 percent efficiency is impossible.                                 

Q: Why is understanding such concepts so important?

A: Having a concept in your head correctly means that you can estimate answers and predict important factors before you work them out. We have a lot of required coursework in engineering and the idea is that these topics are supposed to build on each other. We don't expect people to memorize every single equation and actually keep all those things in their head. But concepts do stay in your head. Those ideas stick better.

What we really want is — when people are practicing or they're going to build a chemical plant or they're going to design a portion of a process for senior design or in real life — we want them, when they have to apply something from thermodynamics, or when they have to apply something from heat transfer, to be able to expect the right sorts of outcomes from whatever changes or input or design parameters they're putting in.

While we know under the current system they will get the math right, part of the design experience is coming up with ideas, selling ideas, before doing all the rigorous math. So that's an area where having the right idea, having the right concept, prepares you to know which math you should be using.

That's actually a big part of what we're looking for in a liberal arts education. If students exit Bucknell - and nothing about their approach to the world, engineering or otherwise has changed — they haven't really received an education. In general, what we're looking for people to say is, "What was my prediction and what really happened? Let me revise my thinking in light of reality."

Q: Tell us about the Engineering and Science Education Expo, or "Gizmo Expo," and what engineering students learn from that experience.

A: Engineers design things; that's what engineers do. You can do a lot of design with just a piece of paper and the computer, but there is a drawback. I can make an awesome chemical plant with pictures and math, and it'll be perfect and it will never blow up and it will never leak and it will never do anything unexpected and it will always produce exactly what it's supposed to produce.

However, just like repairing misconceptions, the way you can achieve some really deep learning is by having people experience what they are trying to do. One of the major driving forces behind the Gizmo Expo is to have them go, very early, in the first-years' careers, beyond the "always perfect" paper design to something they have to make work. In this case, they need to design and build a gizmo that a teacher could use to teach science, math, engineering or technology to kids. We wrap up the project with an Expo (Dec. 6), where there is an audience of over 100 teachers, students, Scouts and volunteers who come to see these Gizmos in action. Making it work is therefore a pretty significant part of the project.

And many of the students entering Engineering 100 really want to make the world a better place. We find a nice synergy on campus with the "Teaching of Science" course, led by Professor Lori Smolleck in education. There are students over there who are becoming teachers, and they could use demos, or interactive gizmos, that would help them teach science in their classes.

Now we can bring all of this together; we can work for real clients and real kids and come up with a gizmo that shows something about science. Our students benefit because it's motivational for them, and we the faculty have the added benefit of knowing our students have closed the loop by bringing a design from paper to reality.



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