Final days at Ypsi High

I'm not good with goodbyes, so I'll just spit it out: this is my last post of the year. This academic year has had its ups and downs, but I certainly continue to learn a lot about teaching, about high school students, and about engaging non-technical audiences in interesting topics related to technical things. In my last two days I had the opportunity to do a design activity, which was bridge building out of candy (the same activity that I did with the students at the Expo in December), and I had a while to talk about my research on vehicle design optimization. These both went really well, and it was a great way to close out the year in these classes.

Last week I did the bridge building activity in the second and third hour classes. Since it was a short day, fourth and sixth hours didn't exist, so I suppose they missed out. I started with a brief slideshow talking about bridges with examples of good design and bad design, and showing them what a truss (triangular structure) is and why they are stronger than square structures. From here I gave them their task: to design and build a bridge (in teams of 3) using only gum drops and toothpicks which would span 11 inches. Ms. Tran helped them out by telling them that their participation would be graded, and winning any of the four awards would give them extra credit on their progress reports coming out the next day. The class was shorter than the activity was designed for, so we only had about 25-30 minutes to design, build, and test. I gave the students 5 minutes to just plan their designs and sketch them out before I even gave them the materials, and then they had about 15 minutes to build. Particularly in the first class, we were extremely pressed on time, and with less than 5 minutes left it was clear that they wouldn't finish, so I changed it from 11 to 6 inches. It turned out that 6 inches was way too easy! The students' bridges withstood all the pennies (weights) that I brought and even went through most of Ms. Tran's change. They did a nice job though, even though we ran out of time during testing. In third hour we were able to get through everything, this time with 8 inch bridges. For the most part, the students got very into this activity, and the group sizes of 3 were good to make sure everyone was able to contribute. I'd do this again.

Today I wanted to finally talk about my research, since I haven't directly shared it with the students yet. I started out by telling them that when I'm not in their classroom, I'm at U of M working on computers running simulations and analyzing data for my research. I used this opportunity to remind them that as a graduate student I'm getting paid to do this research, so it's sort of like a real job. I started out with some videos of the crash and blast simulations that I've been running, just to give them something interesting to look at and grab their attention. I then introduced the phrase "design optimization" and asked them to define it. I'm still surprised at how few students know the term "optimal" or "optimize", but there was always some student that could give us the gist. I then asked what the "optimal" or "best" car would be? Is it the safest car? most fuel efficient? best looking? least costly? fastest? The students often replied that it should be all five, but I suggested that this isn't the case and cited examples of vehicles that are among the best in certain categories, but seriously lacking in others. Next I explained that in order to evaluate cars on these criteria, we have to be able to quantify each of the objectives, and I gave the example that we quantify fuel efficiency using miles-per-gallon (mpg), but in other places they use gallons per mile or liters per kilometer. Next I actually gave them some time to think about how to quantify the other four objectives, and asked them to talk in pairs about them. Most students seemed to actually spend the minute or two that I gave them to discuss this (which I considered a huge success), and in the end they were able to give some good ideas on how to quantify these things. I explained in the end that this is the most important and perhaps hardest part: formulating problems mathematically with numbers. I then continued to talk broadly about some of my research in both the commercial vehicle sector and military vehicle design, discussing the problems as well as some of the things that I've found in my studies. I closed out and asked if they had any final questions for me.

One of my challenges with this talk was in keeping it simple enough for the students to understand and follow, yet still showing something meaningful. In the end I showed less meaningful things, but brought up some interesting discussion topics that the students were able to participate in. I think the think-pair-share activity was useful in that it gave those who were interested an opportunity to think about the questions I posed, and we got more participation this way than normally. Second hour was very receptive in general, and one of the students asked what he should do if he wants to get into vehicle design for a career - I think he was already interested in this area, but my presence might have strengthened that interest, which I consider a success. Third and fourth hours were slightly less engaged in the latter part of the presentation where I discussed my research, but they were still polite and receptive to me. Sixth hour, as usual, was rowdy but respectful, and many of the students contributed to the discussion and asked questions. All in all, I think this was a great way to close out the year, which lets me leave with a fairly positive attitude toward my students and my contributions at YHS. Thank you to everyone who made this experience possible!

Reduce, Reuse, Recycle

No, this post isn't about environmental friendliness. In the last two weeks I gave presentations that I "recycled" from last year, both of which went pretty well once again. Since I used them both last year and they both went well, I allowed myself to be lazy and only made a few minor changes from the old slides. As a result, I can say that they both went well, though not exceptionally so. As is often the case, many of the students checked out early and quietly ignored me for both talks, but I did feel like there were a good number of students who stayed with me and as a result learned a few things.

Last week's talk was about the angles that are important when steering a car. I started out by showing a video that had a Corvette driving along a curvy road before spinning out because of driving too fast and taking the curve too hard. So I posed the question: why do cars spin out? Most of the answers revolved around poor driving or poor car maintenance, so I pushed them to continue brainstorming and come up with the more specific cause: the tires of the car slip against the surface of the road. So then I asked the students whether the wheels of the car turn at the same angle as the steering wheel, and usually got a resounding "no", which is good. Power steering makes it so that we can turn the steering wheel almost a full turn while the wheels only rotate 20 or 30 degrees. Next I asked whether both front wheels turn at the same angle, and most people thought the answer was yes. I spent the next couple of slides showing them why the tires should turn at different angles - the inside wheel (with respect to the turn) needs to turn a little bit steeper because it's revolving around a tighter turning radius than the outside wheel. We then talked briefly about handling and how at high speeds, the tires of a car slip on the road, and if there is too much weight in the back of the car, that might cause spinning out to occur more easily. This was a fairly quick talk (less than 15 minutes), and I did get the impression that the students were engaged and many of them learned a few things or at least will think a bit differently next time they are in a car.

This week I talked about flight. I started out with a cool, somewhat funny video that showed some early attempts at flying and mostly how some elaborate machines broke down after they started moving. We then talked about some of the reasons that we fly (we can go really fast, avoid obstacles, it's safe, it gives the military more options), and then we went through the three main types of aircraft that we see: blimps, airplanes, and helicopters. With blimps, we fill it with a gas that is lighter than air (I showed a periodic table to illustrate what gases are lighter than air), and heat it up or cool it down to make it lift or lower the weight in the cabin. With airplanes, there are a lot of complex forces going on, but the important force is lift, which is controlled by the speed of the aircraft along with the angle that the wings hit the air. I spent a little bit of time discussing those angles, but tried not to talk too long for fear of losing students. I ended by briefly discussing how helicopters work, and how the speed and the angles of the main rotor affect the lift of the vehicle. I think on the whole it was valuable and I think that some of the students gained some higher understanding of the challenges and current methods in flying work.