The things we don't know we know

Today, my fellow grad students and I were launching ping pong balls across the room with a ping pong ball cannon (something physics students are wont to do). And the topic came up of what would happen if (this is what I love about science students--the phrase "I wonder what would happen if..."!!) we poked holes in the ping pong balls. We tried one, and it smashed into the opposite wall the same as the others. However, it had developed a crack from the hole. My cohorts commented, "Hey, it cracked!" I replied, "Well yeah, we put a stress concentrator." To which they responded, "A WHAT?"

Wow! So here is a bit of knowledge I'd thought I'd learned in high school, but which I'd evidently learned in engineering school. I got to explain to them about stress concentrators, and further how plastics are quite notch-sensitive, and concluded with "why were you nicking the edge of the tape with your teeth before you tore off a piece of tape earlier?"

Now I am quite proud at my ability to pull off that example on the fly, from my friend's own action, which he evidently hadn't even thought about before. And I'm proud that obviously my engineering education has come to something more than fancy titles on my resume. But I also have some anxiety that there is evidently less crossover between mechanical engineering and physics than I had supposed. That all these years I've spent learning stuff that they haven't, they've had the same number of years learning stuff that I haven't!

It makes me nervous to think about, but it's also terribly exciting. I get to learn all new stuff in the coming years!