Oct 28, 2009

Story: I'm a klutz

I'm a bit of a klutz. I don't think it's because I have an artificial leg. I just don't think my brain and my body are always in sync.

For example, one day, I decided to turn and walk into the hanging copper letter holder. I don't know why, but after walking smack into it, I realized, I had a scrape on my glasses. The next thought I had was, thank goodness I had glass glasses when I went through puberty. Since we got my glasses shipped from Hong Kong, I would have been twitching with a phantom scratch in my sight for months.

I usually use this story when we cover material properties, particularly hardness - the resistance to abrasion or indentation. My polycarbonate lenses are not as hard as my old glass lenses from my teenage years.

The concrete example helps students generalize their understanding - and I suppose knowing their professor is a klutz is endearing to them. Someone usually pipes up - what about breaking? If glass is hard, why does it break? Ah, good question. I ask for particulars on how it breaks... is it dropped or do you, for example, sit on it, and then it breaks?

This is a perfect segway into the terms, strength and toughness. It twists up the mind sometimes to think of these as different. If we can pile weight on top of my lens, for example, and it doesn't fail, then it is strong in compression. However, if it cannot absorb a high amount of energy put into it, for example, through a hammer blow or a drop on the floor, then it is not tough. Glass is strong and hard, but not tough.

As my sister, the English major, pointed out. Each word has its own definition. In engineering, terms are often different because they are defined, thus measured, differently. Concrete examples help tease out the differences and tie those definitions to past experiences. And apparently, my being a klutz helps students remember those past experiences better.

Oct 26, 2009

Movie: Square peg and round hole

I like to show movie clips when possible so that my students can see the drama of an engineer's world. Apollo 13 is a no-brainer; engineers are everywhere -- and it's one of the few American films where they are the heroes.

This particular scene is one I use to dispel the half-conception that "engineering and science are the same". It illustrates the fact that engineers work within constraints.

Apollo 13: CO2 filter problem

Oct 25, 2009

Joke: Engineers like to solve problems

I like to tell this to students to illustrate that engineers like to solve problems. A lively discussion about consequences to solving those problems usually follows:
A priest, a lawyer and an engineer were about to be executed during the French Revolution. The priest was brought up and laid down. The rope was released but the blad of the guillotine did not fall. He declared it was divine intervention and was released. The lawyer was brought up next. He was laid down, and again, the rope was released. He declared he could not be tried twice for the same crime and was released. The engineer was next, and as he was being laid down, he looked up at the blade and said, "Oh, I think I see your problem."

Insights from cleaning a pan

From An Engineer's Playground
I have an ugly frying pan. It's an All-Clad that we bought a few years ago, but somehow, perhaps through neglect or oily living, it's become sticky ugly. (Maybe that's why Marie doesn't stay for dinner...)

Today, I was in the Chinese grocery store and picked up a curly metal spongy thing - much like a Brillo steel wool pad. At Target, the cleaning section contains any number of plastic or natural fiber cleaning pads designed to be kind to non-stick pans. I can't tell you how long I scrubbed with them (even the 3M heavy duty) with no success. Within about 5 circles with the steel, I saw noticeable change. Within about 15 minutes, the pan actually started to shine. Sometimes the old ways are the most effective.

As I cleaned the pan, I got a bit obsessed with some of the really icky spots which nestled around the rivets. I found myself scrubbing these spots longer, with much more zeal, but with little noticeable progress compared to some other areas of the pan. I finally made the decision to clean over the whole pan, making the pan look better overall, than necessarily perfect in any one area. It reminded me of sketching. It also reminded me of teaching engineering to elementary teachers.

From An Engineer's Playground
Minnesota is requiring children to learn engineering from kindergarten through 12th grade. Elementary teachers are particularly worried about whether they will be able to handle the material, let alone teach the children adequately. But in a way, it is like my pan. In the early stages, it is best to work the whole surface, cleaning away the "easy" spots, giving a sense of accomplishment, and a providing a sneak peek to what a completed job can look like. Another day, I will scrub more around the trouble spots just like a teacher, later, in high school or even college, will be able to teach a student more in depth on a few focused topic.

Teaching breadth is not watering down just like cleaning the entire pan and leaving some icky spots is not cheating. It is an important stage in the learning (and cleaning) and if done well, can inspire one to pick up the task again, with new vigor and motivation. -- And sometimes discovering the old ways can be more effective than new more modern inventions.