Presentations

Thus far I've given 3 presentations in Mr. Tuttle's class and I think each one has been an improvement over the last. I know other teaching fellows in Ypsi High who have given many more presentations than me, but I spend 8-12 hours preparing the powerpoint slides and visual aids for each presentation. This is partly because I am a perfectionist, but it's also because I've seen how displaying just the right diagrams and guiding the students through a certain progression of thought can make confusing concepts quite clear. Anyone who has taken a college class with me knows I hold Professors up to a high bar, and I've been dissatisfied more than once with the quality of teaching at U of M. This motivates me to try and live up to my own standards, and avoid the fumbles I've seen others make. I think the biggest challenge I face with each presentation is determining what level to pitch the material at. In my experience, it is the more involved topics in math, science, and engineering that are the most interesting. If I'm presenting ideas that are obvious then I'm not doing a thing to illuminate the excitement and beauty surrounding science. Presenting obvious concepts reinforces the viewpoint that students can get away with using their intuition on everything; that math and science are only academic constructs that have no place in their lives. Conversely, it is easy to be too ambitious and lose them with concepts that they just aren't ready for yet, which is what happened in my first presentation.

For my first presentation I decided to teach them about a material I study for my research: shape memory alloys. This material can be deformed at a low temperature, but when it's heated up it regains its old shape. So I wowed them with a few different neat demos of the shape memory effect, and talked about engineering applications of these materials. This all worked out pretty well and I got lots of excited looks and questions. However when I got into the science behind the flashy surface level stuff, I lost 'em. I knew this would be difficult so I tried to have lots of pictures, but it was just too much. I think it's still good for the top level students to see something impressive that they can't understand immediately, since it gives them a reason to continue to be curious. There was one girl who screwed up her face as she tried so hard to understand what I was saying, which was rewarding in its own way. Meanwhile the rest of the class tuned out and maybe thought that math and science really aren't their thing. Clearly something had to change.

The second presentation I decided to flip my last approach on its head: start with an interesting application and use it to demonstrate engineering principles, instead of starting with science and building up to applications. I gave a talk on design of submarines. I built a 3 foot long remote control sub for my senior project while I was in college, so I brought it in, talked about how it works, and demonstrated it's operation. This along with a short video about the majesty of nuclear submarines grabbed their attention. From here I could talk about how the bouyancy force has to equal the weight of the sub for it to be neutrally bouyant, how the bouyancy force can be calculated using Archimedes principle, and why you need to trim the ballast to make the sub stay level underwater. Judging from the answers to my questions, and the good questions asked by interested students, I felt like I reached the majority of the students.

Last week I followed the same approach and gave a full hour presentation on design of airplanes. I started off with a 2 minute video of all the failed attempts to fly before the Wright Brothers to illustrate the exploration process. After this, I went into the four forces in flight: weight, thrust, drag, and lift. Using the common experience of sticking your hand out the window of a moving car, I think they got a good feel for the lift equation from simple aerodynamics. Here I wanted to go beyond the traditional lecture format of my previous presentations and make it more interactive, so we threw paper airplanes. (I was amazed: a 1/4 of every class had never made paper airplanes before!) It was a bit chaotic as you might imagine, but we did three different trials with a paperclip in the front, back, and middle of the paper airplanes. From there, we talked about center of lift vs. center of gravity and why paperclip position matters. Then to improve the gliding we modified the design to improve the stability of the airplane and threw them again. With this hands-on feel for things, we talked about why real planes are designed the way that they are by drawing forces and moments (torques). I was really happy the way this turned out. Airplane stability was one of those good topics that wasn't obvious from the beginning, but with just a little analysis suddenly a lot of neat things become clear to the students. Afterwards, two different girls in different classes said that they really liked the presentation, which made me especially happy since I was worried that airplanes and submarines might capture the imagination of just the boys.

I'm thinking the next presentation may be on the design of bridges, but we'll see...