Seems like the new iPhone6 camera is going to be pretty great for physics class.
Special bonus: Two students from honors physics last year dropped by class and jumped right into lab work. It was great to see how quickly they were able to design experiments to show that speed and surface area don’t affect the frictional force, and it gave me a nice appreciation for just how much students grow in a year’s time.
In Intro Physics we’ve started working on circuits using a modified version of the CASTLE materials and students encountered a question about which bulb in a two bulbs in series circuit would light first. This led to a lot of interesting conversations—some students swore they saw one lightbulb light before the other. Then one student suggested we try lengthening the wire and see if we could then tell which bulb lights first. Since this was another good chance to try out the high speed settings on my phone, I went ahead and created these two videos.
My colleague took this even further—he has his kids assume that the electrical activity in the wires was moving at near the speed of light, and then had them calculate how much wire you would need for there to be a 1/240 s difference in time.
For the past week or so it’s been rec time all the time. I ended up with 14 college recs and our school has an internal deadline where they are all due early in the year. I thought I might die.
But two things helped me get through. One was taking Sam Shah’s excellent tips on writing college recs and creating a Google doc with 15 questions that I have each student complete. I try to send this document out as soon as I’m asked in May, and try to send a few reminders over the summer. I still find I have a few people who forget to do this, and sometimes the responses aren’t all that helpful, so I need to keep working on the form.
The other huge help is having my computer read the rec to me for proofreading. I can’t tell you how many errors I’ve caught in my writing using this trick, and it’s dead simple to use.
In Computer Science 3, we’ve been truing to find an authentic way to get students to better understand the value of good coding habits, like carefully naming their functions, and including comments. So my co-teacher and I decided to try a new exercise which he dubbed “coding roulette.”
At the moment, we’re trying to develop an approach to allow you to quickly select one or more members of our 450 person community for a package notification system. The students have come up with a lot of creating ideas for various search algorithms, ranging from a simple last name search, to a chorded keyboard where you would divide the keyboard into 5 quadrants, and just have the user press the appropriate quadrant for the first letter of the person’s name.
So we started coding roulette by asking students to work for 20 minutes on their search idea. Then when 20 minutes were up, we asked students to stop, post their code to gist, and pull down someone else’s code. Then they work for 15 minutes on the code, and we do the same procedure again, so that after 3 round, everyone in our programming class, everyone was worked on every piece of code. At that point, the last person to work on the code presents it to the class in a sort of mini code review/demo. We then talk about how how the code as implemented compares to the original vision of the creator.
The students enjoyed this exercise, and it only took one swap for them to suddenly see a much more pressing need for commenting their work.
Unfortunately, I don’t have a great photo to share, but we have been enjoying the communications platform Slack for a lot of our communication in CS3, and it’s amazing, and also a bit hard to describe. Be sure to check out the demo video.
I’m borrowing a lot of ideas from Dan Anderson’s Computer Science course, and one of the things I really like about his approach is how he’s introducing students to a number of different languages, and through this, helping students to see the strengths and weaknesses of individual languages.
After playing with Lightbot, an admittedly extremely limited language, students were pretty pleased by the flexibility of scratch, which lets them string together an unlimited number of commands and has a far greater palette of commands to choose from. But, we’ve also been recently bumping up against the limitations of scratch, as we most recently saw when trying to implement a simple factorial program via livecoding (an awesome idea from Mark Guzdial). The left side is a solution in scratch, and the right side is the same program in Python.
Students were impressed by the brevity, readability, and intuitiveness of the pythonic approach. One student even recognized recursion from Lightbot, and they sort of laughed at my favorite XKCD Python cartoon.
Today, along with 8 other faculty, I took this bus full of kids to see Ta-Nehisi Coates, author of the must read article of the summer: The Case for Reparations.
The talk was amazing. Coates even made time to speak to our students beforehand.
I think Coates talk was also super challenging for my students (see my Storify post with quotes from Mr. Coates). I don’t think atone has ever talked to them about race or racism in this way before. I’d say our daily existence is much more one of thinking that everyone within our idyllic 400 person community gets along, and racism is something mostly of the past that exists “out there.”
Now here’s the interesting part—my students loved it. Their ideas where challenged and their thinking was pushed hard, but they loved heart someone who is direct and doesn’t talk about racial tensions, but instead simply calls white supremacy and racism out for what they are.
I often think that my students are ready to handle difficult problems from the get go, and a lot of my growth as a teacher has come from learning to strip away scaffolding and hand holding and let students wrestle with challenging problems on their own and with their classmates. I’m always astounded by the progress they make.
It occurs to me that discussions about race and other difficult issues don’t need to be all that different. Students are ready to think about difficult, thorny problems without easy solutions, and they would better off if we let them do so often.
In the past, BFPM has been a bit of a morass for us—we’ve sometimes spent 4 weeks on all the stuff in this unit. This year, our goal is to clear it in less than 3 weeks, and hopefully closer to two. To do this, I’m trying not to get lost in whiteboarding every single problem, and trying not to feel a need to explore every detail the moment we introduce a concept.
In the past, this activity has taken more than 3 days to whiteboard out way through it. Today I wanted to get it done in 40 minutes.
So I gave the class 15 minutes to work on the Free Body Diagrams. I gave them some guidance to focus on being efficient—if they really got stuck on something, they should move on.
After 15 minutes, I passed out 12 1×1 whiteboards and asked each student to draw one of the solutions, intentionally including a mistake. I then put all the boards up in order in the front of the room, and asked students to go and draw correct FBDs above the incorrect ones, while also making a list of pro tips to help us draw FBDs in general.
After we got to near consensus, I walked past the revisions and said “I see some mistakes” and encouraged students to check out other boards. 2-3 minutes of thinking later and every board was correct. I was able to go through and pick out a few more pro tips like drawing in a dotted line for the surface, and highlight how the forces must sum up to zero in all the constant velocity problems and we were done.
Along the way, some students brought up some great questions, like whether the net force must act in the direction of motion of an object, and we were able to use these examples to develop an argument for why FBDs can really only tell us about changes in velocity.
Josh Gates has a great experiment for a Newton’s 2nd law lab using an atwood machine (here’s a related post he wrote about a similar lab with a half atwood). We decided to incorporate this experiment into a group paradigm lab to help introduce BFPM, and it worked incredibly well. Josh has submitted a paper describing this experience in detail to the Physics Teacher, so hopefully, you’ll be able to read about it soon.
I wrote about it a ton on my main blog, but today was a pretty special day in my honors physics class. My students blew me away with their ability to run a physics discussion and think deeply about some difficult problems.
Here’s just one small 2 minute video excerpt:
And here’s a comment that blew my mind from a student after class:
This class was the first time that a student’s comment has ever changed my mind in discussion.
I think this student was pretty surprised to see this happen in physics class, which seems to be about right answers, rather than the many other discussion based classes that are the core of the other disciplines.
This has never happened before, but when working on Matt Greenwolfe’s box pushing activity, students started drawing Free Body Diagrams and then they just got into a spontaneous conversation about the best way to represent forces in the diagram (I had introduced them only very quickly the day before). The big question was whether the arrows should begin on the dot, or begin where the force comes from, and after a little bit of questioning, I was amazed to see how the students were able to question one another an come to a consensus that drawing arrows that begin on the dot is more helpful, and the diagram in this drawing turned out to be the key to that insight, as these students drew their horizontal forces following a different convention than the one they used for vertical forces.