Exploring an Electronic World with Working Model Software

Frank Lee
Engineering Transfer Program, Chair
Science Division
Bellevue Community College
Bellevue, Washington
flee@bcc.ctc.edu

Why use technology?
In the core engineering courses I teach--Statics, Mechanics, and Dynamics--I talk about the concepts, and the textbook has diagrams, but nothing's moving. A lot of the learning experience depends on the students' ability to visualize and wonder: "Okay, how would this thing move?"

But students can't do much wondering when they're just trying to do the calculations. And if they can't visualize how an object is moving, then solving the equations that describe how it's moving is going to be even tougher.

I began using Working Model 2D, a physical simulation software package, to verify with visualizations and simulations the theoretical calculations we were doing by hand in class. With Working Model, the sky is the limit; you can build anything you want.

Bellevue Community College Working Model 2D Working Model 2D Windows demo version MSC Software

On a second level, the software is helpful for doing explorations and analysis--you know, exploring the "what if" questions and applying the concepts. What if we changed this parameter or that? As long as you can do the calculations once by hand, you realize how much work is involved. And you need to make sure you can do it right. But when you get to the "what if" questions, working on those by hand would be really laborious, doing the number crunching over and over. So that's when you want to take advantage of a computer program or write your own code. You let the computer do all the number crunching, and then you can start exploring: What if the person's weight was double a certain amount? Or what if I tripled this force, what would happen to something else?

At Bellevue Community College, the third largest institute of higher learning in the State of Washington, the coursework mimics the first two years of a four-year degree; then students transfer to an accredited four-year college or university that offers their discipline. The courses are designed to transfer as the equivalents of certain courses at the university, so the students can hit the ground running when they transfer.

The courses
Within the Science Division, I take care of the sophomore-level engineering core courses: Statics, Mechanics of Materials, and Dynamics. These classes last a quarter rather than a semester and have about 15 students each. Statics covers the mechanical forces on systems, which we analyze for equilibrium. At the end of the course we start looking at what's happening inside a particular material, at what kinds of forces must be inside that material in order to keep the system or object from falling apart.

In Mechanics of Materials, we start analyzing the stresses inside the material, based on a number of theoretical assessments. This applies to developing new types of materials or doing design work, such as looking at two different geometries and deciding which one you want to use to make the material strongest or stiffest, to make the bolts strong enough to hold the object together--whatever your design and criteria.

In Dynamics, the systems we look at aren't necessarily stable, they're moving--and the work analyzes forces that involve mass times acceleration.

The strategy
I use the Working Model 2D program as a demonstration in class to verify the theoretical material and equations I'm teaching. We work with vectors and graphics, and we do all the number crunching. In addition, the publishers of the textbooks I use include a CD-ROM that contains pre-canned simulations done in Working Model.

I don't require the students to buy and use the software in class. In addition to the added expense, there's a learning curve associated with starting to use a new piece of software, and that could be a barrier to a student struggling with just trying to learn the class material. I think the software package is fun enough that it can motivate students to say, "Hey, I want to learn this." So I use it for demonstrations, and it definitely helps in visualizing the concepts.

Say, for example, we're studying relative motion. The students get the textbook theory; they work through the topic with vectors and graphs, and they calculate--they do all the number crunching. And they get a result. I tell them, "As engineers, you'd be asking, 'Is this result correct? Did I make any mistakes?'" So I build the model in Working Model, we run it, and we see how close we can match it up to their results. One caveat that I always tell the students is that this is just another software package; it's doing the calculations, and it may be wrong. You always have that doubt whenever you're using any software package. There could be minor errors in the program. Ideally, you'd have the laboratory in which to build the physical model, but having laboratories for design projects are expensive and usually reserved for more advanced work in upper division majors' courses.

The learning technology
Working Model: The Working Model software, developed by MSC. MSC.Working Knowledge, gives faculty, students, and professional engineers drawing and mathematical tools with which they can build complex models that simulate the real world. According to the MSC.Working Knowledge website, these tools allow users to "design, test, refine, and verify mechanical, biomechanical, an structural assemblies." Working Model is Windows-based and a demo version can be downloaded or viewed from the website.

I use two textbooks in my courses: Vector Mechanics for Engineers, Statics SI and Vector Mechanics for Engineers, Dynamics SI, both written by Beer and Johnston. These both come with CD-ROMS that contain pre-canned simulations based on Working Model, as I mentioned before. Some of these simulations are interactive. You can vary some of the initial parameters--they're like little programs; they have textboxes that you can use to change the initial conditions and then run the simulations.

In one simulation, for example, a diver is jumping off a tall cliff, with waves coming towards the shore. The diver is timing the waves, because when he jumps, he doesn't want to fall into the water at the low end of the wave. So when should the diver jump? You guess, and then you run the simulation and the diver dives. If you guess wrong, the diver falls into the water and hits his head on the ground. If you guess right, the diver enters the water at the wave's peak, and he's safe. In this problem, the student has to analyze projectile motion--the diver jumping off the cliff--with a second variable, the speed of the waves. Mathematically, the student has to solve this with either a second-order or third-order polynomial.

The results
When I do the demonstrations, using Working Model, the students love it. A lot of them will say, "Hey, let's try this," and if I know how, I'll change the parameters and try it. Then we run the model and see what it does. I see them doing the exploration and analysis in their minds.

On a personal level, I think using the Working Model 2D software is worth the effort, because it's interesting. On a classroom level, it takes work. You've got to have the computer equipment in the classroom--and if you're supporting it yourself, it's a big headache. If you have other people supporting it, that's also a big headache. All the same, I do think that the learning technology opens up the physical world to the students--it's just a cool program. I use it to help my students figure out the correct computations. The software, whiz-bang, is great. But just because you can make the software run doesn't mean you know the concepts. Helping them learn the concepts is what we're going for.

If you have any questions about our project, you can contact me at: flee@bcc.ctc.edu