Every year, the University of Washington puts on Discovery Days where the engineers showcase their research for students in area schools (K-12). My lab has always participated, but our research does not have a great deal of hands-on work due to the sub-micrometer dimensions of our devices. This year, we decided to change that after a discussion over drinks in San Francisco at a conference a few months ago.
We decided to make an interactive display with posts about 10,000 times larger than the ones we use in the lab. We wanted the students to understand the concept of deflection showing the force of the post based on an equation, so we made the bendable by using acrylic. We had different sizes, different materials, and used strain gauges to display the force. While building the contraption, there was a moment where we worried about the ability of the students to break the acrylic rods, so we put on our safety glass, put all of our weight into it, and could not break any of the posts. Feeling content that we were stronger than 12 year-olds, we finished setting up the experiment, and were feeling good when the day started on Friday.
Within five minutes, during the first groups attempt, the first post broke!
We decided to encourage the students to be more careful as the day progressed, and only had one more post break before the end of the day. By the time 2pm rolled around, we still had a working setup, and I think the kids actually learned something about how dimensions of posts affect the ability to pull on them.