There’s the vacuum bazooka that shoots a ping pong ball at the speed of sound, blasting clean through a set of aluminum cans. There’s the cast iron “bomb” which goes off inside of a plexiglass case. Not to mention the set of 100 mousetraps which goes off in a minute-long frenzy of snapping. Brian confides that the latter is one of the most difficult and nerve wracking to prepare.
Andersson’s job is to set-up, repair, and build lecture demonstrations. Sometimes this involves building demos from scratch such as the pair of phonebooks with interlocking pages that requires the force of two heavy trucks to pull it apart. The phonebooks are one of Andersson’s favorites because it is fun to see confident students attempt to pull them apart. Other demonstrations, such as the vacuum bazooka have been modified by Andersson to be more effective. After seeing the bazooka in a publication on lecture demos he decided to build one, he created a rack for the pop cans so that they would be held in place and show the power of the ping pong ball as it comes out of the end of barrel.
Demonstrations in general have a unique ability to get students involved in the classroom. Andersson says that he got interested in lecture demonstration during his time as a student at the University of Minnesota. “When I went here, I didn’t see a lot of demos. Many of the faculty weren’t using them and now they are.” Andersson is glad to see that has changed in recent years. “A lot of the faculty were pleasantly surprised to see how popular they were,” he said. Andersson said that students and teachers alike appreciate the break from the lecture format that the demonstrations provide.
You can see many of School of Physics and Astronomy’s catalog of physics demonstrations as they have been filmed by Andersson and various student workers. Andersson says this resource is frequently used by groups outside the University that don’t have access to such an exhaustive supply of demos. He estimates the University has the second or third largest collection of lecture demonstrations in the US.