Beautiful Physics: A Summer Mini-Course

ESU, the Enrichment Studies Unit, is a really neat program here at Queen's. Instructors (usually grad students) can submit a proposal to teach a mini enrichment course on pretty much any topic they are passionate about. A diverse range of proposals are chosen, and the instructors set out to design engaging curriculum on their favourite topics. I think it's an ideal way to run these courses - giving autonomy to instructors to teach what they love.

So naturally, I wrote a course on... the history of penguins. I'm kidding, of 'course'.  My course was called "Beautiful Physics: Light and Sound".  I took a very different approach to the teaching style I used this past year in tutorials.  My whiteboards only came out twice - first for a boggle-style competition brainstorming all the different types of waves we knew, and later for a pictionary review game - we didn't do any problem solving because the students' math skills were too much of a barrier.

Instead, I went for a purely conceptual course with the goal of inspiring questions and finding a couple answers. One thing that I found interesting and encouraging: even without math, the course remained challenging for the students - this was important to me since it was an enrichment course for keen students. (Though a custodian saw the play-doh we used for stop motion, and refused to believe that I wasn't teaching kindergarten students - I was mildly taken aback. I still like play-doh... )

So we did a waves a hundred ways. The human longitudinal wave was a fun one, since it involved knocking over your friends. Similarly, the refracted human wave - lines of students walking quickly on pavement (representing light in air) and slowing down when their feet touched grass (representing glass) worked well for creating an experience of refraction.

We applied refraction to water waves, asking non-intuitive questions like:

As you can probably tell, the "lectures" were mostly done using Peer Instruction. It's easy to do and is the most popularly adopted strategy coming out of physics education research. So at this point - as a 'reader' in my class, you get to pull out your A B C D flashcard and vote for the most likely explanation you can think of for why water waves always move towards the shore. Then, find a friend, discuss the question with them, and then return to reading.

Wait - did you really discuss with a friend? Hmm, I think you should share the best explanation you can come up with - and see if you can tie it to refraction - in the comments. Next week, I'll tell you the rest of the story ;)

We went on to learn about refraction of different frequencies, chromatic aberration, and of course the question:

We looked at dispersion of both light and sound. We did sound dispersion with one of my favourite simple demos - try hitting the end of a metal slinky while holding the other end up to your ear. It's Star Wars! Not kidding! Buy a metal slinky right now and try it. Yes, right now. What happens is this: a clap or tap is made of a thousand different frequencies (or pitches) - high ones, medium ones, low ones, etc. But high frequencies travel faster in metal than low frequencies, so the high ones make it down the slinky and to your ear first... then the medium ones... then the low ones. So you hear Star Wars!

The other place we looked at dispersion was in optical fibers. We learned that in multimode fibers, light that bounces around (by total internal reflection) a lot in the fiber has to travel further to get from Kingston to Columbus than light that goes basically down the middle of the fiber without too much bouncing. The light that travels further takes longer to arrive; therefore the pulse smears out in time:

That's a real problem because then the skype conversation can't be interpretted by the computer in Columbus, and the conversation would fail! So what would you do to fix the dispersion problem in optical fibers?

Once again, discuss, drop me a question or two, and let me know what you think would work to reduce pulse dispersion in the comments! I'll explain the solution next week :)

So as you can tell, we did a lot of waves. Here's a sense of the topics we covered and questions we asked. If you're teaching anything related to these areas, feel free to drop me a note and we can share lesson plans!

• Moire patterns  - why should you not to wear a striped shirt on TV?
• Thin film interference - why do you see rainbows on puddles of gasoline?
• Doppler effect - how do we know that the universe is expanding, and why does the pitch of a motorcycle engine changes as it drives past you?
• Reflection - why do you look upsidedown in a spoon?
• Virtual images - how to make pigs fly (or look like they are)
• Total internal reflection - how does data travel to talk to a fabulous Jeremy via skype, or how do you trap a laser beam in a bending stream of water?
• Polarization - how do 3D movies work?
• Resonance - what do the Tacoma bridge (see this clip: http://www.youtube.com/watch?v=3mclp9QmCGs), a flute,  a swing,  a guitar, a singing bowl,  and a washing machine have in common?
• Overtones - how do you force nodes on a guitar string?
• Quantum, Relativity and other fun topics that students requested we learn about

Whew! That explains why I slept for 12 hours on Thursday night! So as you can guess, I was worried they would forget everything as soon as they'd learned it. I decided that I wanted the students to at least remember one thing, and gain a general sense that physics is the coolest subject ever. So the students made stop motion movies in groups to teach one concept to their friends. 

This group made a video about how a rainbow is formed. I was pretty impressed with the quality of the physics they explained in their video! http://www.youtube.com/watch?v=OR0SOlJ_9d0. Other groups had more trouble explaining the physics, but did have a lot of fun making their video - which was half of the goal. This group went for a Harry Potter style Schrodinger's cat video. http://www.youtube.com/watch?v=f1VBMc_8kkI&feature=youtu.be. And this group did a creative mix of a Schrodinger's cat and the Doppler Effect to tell a story of resuscitating the poor cat after he was observed to be in the 'dead' state. http://www.youtube.com/watch?v=8H-Qa5cbLXM&feature=youtu.be. It was a bit of a tricky call for me to decide if their choice of music for the credits fit the requirements of PG only. I decided this was a battle I wouldn't pick.

There were other battles I did pick. We had some sad issues with emotional and verbal bullying in the class. But I decided to take a different approach than the traditional scary "stop the bullying" approach because I know they've all heard that talk before.... and the bullying obviously hasn't stopped. So I chatted with the class about my experiences with bullying. The fact that empathy and interpersonal skills end up being way more important than putting people down to get ahead. That it's actually a good thing to be a bit quirky and have a personality that stands out when you're looking for a job. That it means a lot to have learned that you can persevere even when life is tough.  I think it helped that by the time we had the chat on bullying, they (including the bullies) liked me enough as a teacher, and were quite surprised to hear I was just like the kids who they were excluding and calling names.  

One of my goals in teaching the course was to show my students that physics goes way beyond our stereotypes as a subject that's simply about trains, airplanes and blowing things up.  It's a creative and beautiful subject that needs all kinds of people - men and women, introverts and extraverts, silly and serious, etc.  I hope the students took that message home. But I hope they took more than physics home. I hope they learned a bit about treating each other well too.