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The app I need right now

March 19, 2020

So I and every other teacher right now are scrambling to get ready to teach school online. Here’s a problem I’m grappling with that I would welcome your advice.

In my Geometry class, we do a lot of group problem solving on wall mounted whiteboards using problems from the Exeter curriculum. It is so helpful for me as a teacher to be able to walk around the room, see students work, ask them questions, give them feedback, and then return later to see how their work has progressed.

I’ve been wondering a lot about what this might look like online. We’re using zoom, and of course there are break rooms, and even a rudimentary “whiteboard” built in where students could finger paint their work. But the reality is, most kids will be doing math work with pencil and paper, and it seems like it will be very hard for me to see that work as it progresses.

My students have all gotten very used to submitting scans of their written math homework using scanbot each night, and this is a great tool for seeing what students have done, but it isn’t seamless enough to really be useful for students to share their math work as they are going.

Here’s what I want—I want an app that allows a student to take a photo of their work. When that student’s work is photographed, it’s added to our class, tagged by student, date and time. Then all of these photographs would be nicely presented to me some way so that I could quickly see a students work, or step through their submissions. It would be extra awesome if I could some how annotate or give feedback to a student’s photo.

This seems like it would be pretty efficient for a student who was working on math and had their phone next to them. They’d just open the app, take a photo, and the work would be there for all to see.

I know students could just hold their notebooks up to a webcam, or take a photo fo their work, air drop it to their laptop, and then screen share. There are also lots of ways to do this saving to Google drive and other such cloud storage tools. But all of these seem to clunky to really foster conversation about math while students are doing it.

Are there any tools out there I’m not aware of that could do this? Is there some other approach that might work?

Challenging Coronavirus with Connections and Puppets

March 16, 2020

My school, just like every other school in the world, has told students not to come back from break, and asked faculty to begin to make plans for virtual school. If you check twitter, you’ll see it’s filled with plans and ideas for teaching virtually, and there are a ton of great resources there. More importantly, there’s a real community of people out there who are lend advice, listen, help out and so much more.

One idea that has stuck with me in the past two weeks is this one from Evan Weinberg, who’s been teaching online for the past five weeks:

At the moment, so much is uncertain about how our school is going to do virtual school—are we going to try to keep to our schedule? How can we teach students in 10+ time zones synchronously? I’ve decided to stop trying to think about possible lesson plans and just focus on thinking about how I will try to maintain those connections with my students. In that regard, this is one of the best things I’ve read on twitter (click through to see the amazing letter this professor sent to her students):

As my two daughters (now 9 and 5) have had their first day of no school, I was reminded just how important this was when we sent an email to a friend we made in Norway last year this morning. When we left last summer, we said we’d keep in touch–our daughters were best friends. But life got busy, and this was our first time reaching out. A few hours later, my 9-year-old, Maddie, and Barrett, her best friend, were taking on FaceTime.  While I was working on lunch, I was tuning in and out of their conversation—at first they were awkwardly asking each other questions, then being interrupted by little siblings, and then spending an amazing amount of time playing around with emojis, but soon Maddie was giving Barrett a tour of her house, and then they sat down and played Legos together. Barrett aimed the iPad at her lego set, and asked Maddie which lego character she wanted to be. Then what did she want the character to do, and on and on. They played legos for more than 20 minutes, and it was an amazing thing to see. These are the moments we are going to need in the weeks ahead, more than any lessons on math or social studies.

IMG 8603

I live on a boarding school campus, and it is teeming with kids of all ages, none of whom can play with each other thanks to social distancing. A few years ago, my wife started Eco-Kids Club, an environmental club for faculty children that meets most Sundays and does fun projects to help or learn about the environment—learning about recycling in our state, hiking in the woods, painting kindness rocks and more. Obviously, Eco-Kids club is on hiatus for the coronavirus, but it got me wondering what if we could find a way to build some connection online.

So after some thinking, I sent out this email to faculty parents at my school:

Calling all Ecokids! We need some eco-superheros for the first-ever eco kids superhero virtual puppet show! You can be a hero, save the world, and do it all from the comfort of your home.

Diana and I are planning a virtual puppet show for all eco kids—in a few days, we want to invite all of the eco kids (and their parents) to perform a virtual puppet show via zoom that we are going to design, record, and share with the community.

Here’s what we need from every eco-kid:

Make a puppet of your eco superhero: Recycle some of the stuff around your house and that you find in nature to create a puppet of your eco-superhero. Be creative—it doesn’t need to be fancy. If you’ve got some extra time and want to make some props to go with your superhero, go for it!

Take a picture of your puppet, give it a name, and tell us the story of your superhero in a couple of sentences. What are your superhero’s superpowers? Where do they come from?

Get your adult to send me an email with the photo, name and a sentence or two about your eco-superhero.

For example, Ada wants to create an eco-bunny whose superpower is hopping around the forest and picking up trash.

I will compile all these photos and descriptions and share them back with all of us.

Once we’ve got our cast, we’ll spend half an hour writing a very simple script where our eco-superheros save the world. We’ll have this writers meeting on zoom, and we welcome everyone, even if you didn’t get to make a puppet.

Who can participate: Anyone! Even if you’ve never been to an eco-kids club meeting. If you’re an older kid, we could really use your help in working with our team to come up with a script. Adults—you can make a puppet, too!

On Friday, we’ll get together again on zoom and we will film our puppet show, and share it with the community, hopefully teaching everyone that when the world needs a hero, sometimes, you can just make one up.

Parents, we don’t want this to create work for you—we are hoping this will be a nice small project for your child to work on one afternoon, and a couple of opportunities to talk to other kids on campus virtually as we work together on a fun project. If you’ve got ideas for how to make this better/easier/more fun, we’d love to hear them.

If you think you or your kids would like to participate in this project, please email me so that I can add you to the mailing list for future communication.

Tentative schedule (we’ll poll all participants to find times that will work best)
Wednesday 4pm—submit a photo of your puppet, name and 2 sentence description.
Thursday 10am-11am—scriptwriting meeting
Friday 10am-11am—rehearsal and filming of the final puppet show

I’ve gotten three replies, which gives us half a dozen or so puppets for our production. I’ve never done anything theater-related before, and I was super relieved when the daughter of our wonderful Theater director decided to join this project. Hopefully, you’ll see what we put together next week.

Once we get past all the schedules, assessments, and other details about what virtual school will look like, I hope we’ll be able to find some time to think about how we will create real moments of connection for our students using the incredible tools that are available to us—the very tools that we too often malign agents of distraction and disconnection.

Pivot Interactives and Tychos—even better together

October 8, 2019

I’m a huge fan of physics teacher written software. At the moment, I think three of the most useful pieces of software for physics teaching are written by physics teachers:

  • SBGbook: This is the best standards based grade book I know of, created by Josh Gates.
  • Pivot interactive: One of the most easy to use tools for video analysis, featuring an awesome library of Direct Measurement Videos, where students use a virtual meter stick and stop watch to make measurements of objects in the video. Pivot was created by Peter Bohacek, and he and his team of incredible students have done some amazing work building a huge library of chemistry and biology videos that make it possible to assign laboratory work as homework
  • Tychos: Tychos is an amazing platform for creating computational models in the browser. It was created by Winston Wolff and Steve Temple, another physics teacher.

If you know of other physics teachers who have created pieces of software, I’d love to hear about them. I think Jeff Hellman, author of Planbook was also a physics teacher before he became a full time developer.

In this post, I’d like to describe how we are using two of these tools, Pivot and Tychos to help our students explore motion, and better understand the notion of a model.

Our Intro Physics students (mostly 10th graders) have just finished their study of the Constant Velocity Particle Model, and we wanted them to get a chance to do some sort of practicum to test out their understanding. Rather than have them do the classic buggy collision lab, we decided to let try our Pivot and work on this Rolling Ball Challenge. Students were already familiar with Pivot from an activity we did earlier in the unit, and after some hiccups, they all found it very easy to use and even fun. Students can directly measure the position of each of the balls, and enter their measurements directly into a simple spreadsheet on the webpage. From there, they can plot their data and perform a linear regression, again, right on the webpage. And finally, the cool part is after making measurements of a segment of the video before the balls collide, they can test out the prediction they get from their mathematical model on the full video.


This worked out great for most of our students. In 30 minutes of homework time they were able to successfully model the collision and test their preciction.

On the next day, we wanted to introduce computational modeling with Tychos, so we gave students this partially completed simulation, and a carefully scaffolded set of instructions.

Here’s what students see when they open the simulation and run it for the first time.

The instructions walk them through the steps needed to make the Tychos simulation match what they see in the video. They have to change the initial position of the purple ball, change the initial velocity of the red ball, and then add a line to the calculation tab to update the position of the purple ball. All in all, by editing two lines of code and writing another two, they can build a working computational model. They can even use the example in the code to add the position of the purple ball to the position graph, and change the sizes of the balls to match the bowling balls from the experiment. After all that, they can then step through to find when the balls collide.

If students come in with working mathematical models, it takes only 20 minutes or so for them to follow the instructions to figure out how to change the position and velocity of the objects in the computational model. Once they test their model, they notice something very interesting. The collision in Tychos takes place well before the actual collision in the simulation—why is that?

This is when we look back at the Pivot experiment, and how we measure data. I project this image, that shows the ruler the students used to measure the position of the two balls.

Very quickly, someone realizes that in Pivot, we were measuring in the position of the ball to be the location of its leading edge (right side for the red ball). We did this because it makes for easy measuring. But for Tycos, it automatically assumes that the position of the ball is the center of the object. I ask the students to think with their partners about how they might modify this simulation to account for this difference, and soon, some group realizes that if you push the starting positions of each ball out by one radius in Tychos, the motion in the computer model will match the motion in the video.

Once we did that, we got great agreement between our simulation and the video, which was wonderful. More importantly, I think students got a much better appreciation for what a model is, and in particular, what we mean by the notion of “particle model” and how we can modify our model to account for the behavior of extended objects like bowling balls. It’s even better that we could see this in the very first situation we tried to model.



Certianly, this exposure to Tychos was heavily scaffolded—the point was to get students to see that they could use a tool like a computer to build a model of a situation to make predictions, not to understand the ins and outs of the Tychos javascript syntax, which we will surely get to in future lessons. This didn’t stop students from appreciating that they’d written their first program, and my students were almost universally excited to work with both of these tools again.

Climate week warm up—let’s analyze some data

September 21, 2019

This week is climate week, and on Friday, I wanted to have a short assignment that would get my students thinking about climate change before we headed out for our observance of the worldwide climate strike.

I decided I would create short warm up activity where I would give students a data set of some quantity. I anonymized each data set so that all students knew is that they were analyzing a time series of data for some quantity and asked them to spend 5 minutes analyzing and making a graph, and then we would share our work with the class. After each presentation, I then revealed what the dataset was.

Here’s the data I used

  • Data set 1: CO2 concentration from 1958.
  • Data set 2: Arctic Sea ice extent in September for the past 40 years
  • Data Set 3: Global temperature anomalies for the past 140 years (January Measurements)
  • Data Set 4: global Temperature Anomalies for the past 140 years (September measurements)
  • Data Set 5:Area of the Agassiz Glacier in Glacier National Park for the past 120 years

I shared an empty Google slides presentation with the class, and asked each group to produce one slide with their graph and any observations they made in 5 minutes of analysis.

Here’s the reveal slide deck I created which explains what each of the datasets are.

This turned out to be a great 10 minute activity. Students were able to figure out easily how to make scatter plots in Google sheets, and came up with all sorts of other insights. Everyone was taken aback when they realized the origin of each dataset and its implications.

Teachers Coding: exploring CalDav files

August 25, 2019

It’s the start of the school year, and for me on of the big mundane tasks is getting my calendar set up for the school year. Our school’s home-brew SAS has this great feature that will generate .ics file containing all of your classes that you can import into Google calendar or any other calendaring program. But it has one problem—all of your class data is in the single file. Since we have a new rotating schedule, I was hoping I might be able to put each class into it’s own calendar in order to let me better see how a particular class is mapping out through the upcoming weeks.

When I thought about it for a bit, I realized this was a great opportunity to put my coding skills to use. I knew an .ics file was basically a text file that listed all of the events to be imported into the calendar. I opened up the calendar file in a text editor (Atom, in this case) and took a look:

Screen Shot 2019 08 25 at 11 23 39 PM

If you look closely at this file you see the structure is pretty simple. The first 7 lines are the header that sets up the calendar, and then every event begins with a BEGIN: VEVENT and ends with a END:VEVENT 7 lines later.

That got me thinking that I could write a python program that would find the first event, and then parse it in 7-line chunks, writing each chunk into a file based on which class it was associated with (the SUMMARY line).

I knew the python is great for this thing, but I’d forgotten the finer points of reading and writing files, so I Googled it. I also didn’t know about how I would parse the text file in 7 line chunks, but googling “parse text file n lines at a time python” sent me to this very helpful post that introduced me to itertools and the islice function which does exactly what I needed.

Here’s the program I came up with (link to code on Github Gist):


If you’re interested, here’s a 5-minute screencast where I explain how this code works

All told, it took me about 45 minutes to write this code, which is probably close to the amount of time it would have taken me to just cut and paste the original file into 4 separate calendar files. I’m also sure there’s some regex expert out there who could have done this in 5 seconds, and if you’re reading this, I’d love to hear about it in the comments.

If you were at my school, or happened to have a similar calDav file containing events with the same name that you wanted to separate into individual files, you should be able to modify the search strings in line 27, 31, 35 and 39 to whatever you’re looking for, change the names of the output files in the first 4 lines and you’d be good to go.

Now, I’ve got a much better idea of how CalDav files work, and can think of a lot of ways to modify this program:

  • If I knew all the days I was going to give a quiz in a class, I could put together a file that would list all of the quiz days to share with my students.
  • I could modify this program to calculate the total number of class periods or total minutes I have in a class.
  • I could export my Google calendar as an .ics file, and then use a program like this to analyze all sorts of questions like if I had logged my workouts, how often do I workout in the past year.

Measuring the length of a pendulum with a microbit

June 12, 2019

Here’s a write up of another activity I’ve been working on as part of my sabbatical.

In college, I remember a dean telling us the joke about the student who was challenged by their professor to measure the height of a building using a barometer, and all the ingenious ways in which the student came up with complete the task: tying a piece of string to the barometer and lowering it from the side of the building to measure the heigh, dropping the barometer off the top of the building and measuring the time it takes to hit the ground, offering the barometer as a gift to the building superintendent in exchange for the height of the building, and more.

Inspired in part by this joke, I decided to see if we might be able to use a BBC micro:bit to measure the length of a piece of string. First, I want to give a serious shout out to the micro:bit as a pretty amazing tool for exploring computing. They are small (2in x 1in) integrated circuit computers that include an array of sensors (light, temperature, accelerometer, compass), a 5×5 LED display, 2 physical buttons, 25 pin outs, and bluetooth wireless connectivity. They’re also cheap ($15) and very easy to program in a block based javascript, or text based python. The platform has a ton of accessories and curricular materials, and seems to be in pretty wide use across the UK and Norway, and probably many other places as well. Microbit is the easiest microcontroller platform I’ve ever worked with, and I think they would be an ideal platform for any middle of high school STEM class looking to add some embedded systems programming to their work.

When I first started playing with micro:bit, it took me about 10 minutes to follow these instructions about Live data logging with Python and Mu (a great beginning python editor for programming micro:bit), and suddenly I had an accelerometer that could wirelessly transmit its readings to a second micro:bit serving as a receiver connected to my computer. This got me thinking, could I use the micro:bit as a pendulum?

Here’s a description of what I did, with some ideas for how to turn this into an actual activity for students in physics class.

Measuring the length of a piece of string with a microbit

The microbit is just about the perfect size to serve as pendulum bob, and it’s easy to attach a battery pack and string through one of the pre-drilled connection holes.

The first thing I needed to do was modify the program from the live data logging example to calculate the magnitude of the acceleration, rather than logging the 3 components for the x, y, and z axes. Thanks to the great documentation of the platform, and the built in tooltips of the mu editor, I was pretty easily able to come up with this program for the accelerometer:

from microbit import *
import radio
import math

while True:
a_x = accelerometer.get_x()
a_y = accelerometer.get_y()
a_z = accelerometer.get_z()
a_mag = math.sqrt(a_x2+a_y2+a_z**2)

and the receiver program was unchanged:

from microbit import *
import radio

while True:
message = radio.receive()

The beauty of the mu-editor is that it will automatically graph any data that is displayed using the print function with its built in plotter. (To take advantage of this feature, the data you print must be sent as a tuple, a single data value followed by a comma, and the radio.send function requires the transmission of a string, so this is the reason for the slightly strange notation of the radio.send argument in the transmitter).


Unfortunately, the mu-plotter is very limited in terms of what it can do—you can’t rescale the axis or do anything to manipulate the data. But mu-python also automatically saves each data run as a .csv file inside the “data_capture” folder within “mu_code”, which you can import into a spreadsheet. Once you’ve imported the data into the spreadheet, you can add a column of time measurements (this program takes readings every 20 milliseconds), and then graph and fit that data.

Since Geogebra is heavily used in Norwegian high school, I decided to try my hand at it for fitting sinusoid data. After pasting the data into the spreadsheet, you need to create a list of points, using the toolbar as follows:


You can then use the FitSin function to fit the list of points:

Knowing that the angular acceleration of the pendulum can be written in general as

\theta(t)=A\sin\left(\omega t -\phi\right)+C

The angular frequency for this pendulum must be 11.32 rad/s.

For a simple pendulum,

\omega^2 = \frac{g}{L}

which we can rearrange and solve for L:

L = \frac{g}{\omega^2}=\frac{\unit[9.8]{N/kg}}{\left(\unit[11.32]{rad/s}\right)^2}=

Hmm—something here isn’t right. It’s calculating a pendulum that is 0.07 m long.

Update: I realized the problem seems to be in the code—the sleep(20) statements in the both the pendululum and the receiver seem to combine to making the actual time between data points 0.04 seconds, rather than 0.02 seconds. Taking this into account would make the angular frequency of the pendulum 5.66 rad/s, giving a much more reasonable value for the lenght of the pendulum as 0.30m.

Some updates to Physics Coach, we’re ready for beta testers

May 27, 2019

Note 2 (May 28): I think I’ve fixed the bug, but if you encounter an error loading the site, I’d greatly appreciate you reaching out via twitter, this blog, or email. 

Note: it seems like the site has a bug I missed and isn’t loading in production. I’m traveling now, but will try to take a look at it tonight and fix it.

When I announced Physics Coach a couple of months ago, I thought I was just a few edits from being done. Of course, I’d totally forgotten the lessons I’d learned from reading The Mythical Man Month back in college. But with two more months of tweaking, I’m ready to share a beta version of Physics Coach complete with a few new features. Also, I again have to send big thanks to my former students, Holly, Yousaf, and Leo who were amazing pair programming companions for much of the development, and tremendous earth shattering thanks to Jason, a totally random reader of my blog who offered to help with the project, implemented a bunch of features and guided me through countless challenges.


New Features:

  • Support for multiple courses: it’s now possible for teachers and students to be enrolled in multiple courses. Practices completed for a course also only appear in that course.
  • Streamlined interface: Rather than ask three different questions at the end of each practice, Physics Coach just asks students to rate how well they accomplished their goal, notes on their practice, and write a question they thought of during their work.
  • More data: Practice cards now show show more information, including the practice time, and emojis to indicate how well you accomplished your goal (🔥🔥 = accomplished much more than your goal). The question mark icon in the corner also indicates whether you have an open question associated with this practice (red= open question, green = closed question).
  • Open and Closed Questions: after each practice, practice coach asks you to write a question that you still have. By default, this question is considered unanswered or open, until you go into the practice card and mark it is answered, which will change the color of the outline of the textbook, and the question icon on the practice card.


  • Push Protocol: Back when I assigned homework consisting of a number of problems for students to solve, it often happened that students would come in the next day talking about how they struggled on a particular problem and spent an hour or more without making any progress. This sort of frustrated practice is a major detriment to student learning—it causes great frustration, decreases student self confidence, and can quickly lead to the student hating physics. To prevent this, I took some inspiration from Cal Newport, and asked students to recognize when they hadn’t made progress on a problem for 5 minutes, and in these moments, to write everything they’d tried to solve the problem, a question that would help them to get unstuck, share this with their teacher and then to move on completely from physics and start working on something else.I’ve created something similar in Physics Coach—once 5 minutes passes, the “I’m stuck” button becomes active, and if a student finds that they can’t make any progress on a problem for 5 minutes, they should press this button and will be asked to document their work, and write a question that would help them to make progress again.
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Possible future directions:

  • Creating summary page: this might show your recent practices, or a graph of your feeling of accomplishment over your most recent practices.
  • Push protocol alerts: I’d like to create setting where the teacher would get sent an email when a student submits a push protocol practice, so that the teacher could respond with help.
  • Comments: I’d like to add in the ability for teachers and students to add comments to their practices and questions.
  • A question tracker page: I’m thinking it might be helpful to pull all of the questions from practices into their own page so that students might be able to browse and review those questions.
  • Practice sharing: It might be useful for students to be able share their practices, especially push protocol practices, with other students in their class so that they can get feedback from their peers.

At this point, I really need some feedback from users to decide where to go with this app, so I think I’m ready to turn it over for beta testing. You can begin using the app right away. Here’s how:

  1. Go to and login with your Google account (at the moment, only users with Google accounts can use Physics Coach).
  2. To experience the student side of the app, enroll in the test course by following this link, and clicking the request to join button.
  3. To get set up as a teacher, please complete this short beta test request form, and I’ll convert your account to a teacher, which will then let you create your own course, and enroll students by sending them the link to your course.

That’s it. I’m a bit bummed I wasn’t able to get this app out earlier in the spring so that we might be able to get some real student testing. But I appreciate any testing and feedback you might be willing to share over the summer.