Tag Archives: labs

Contextual Feedback Using GitHub Pull Requests

After reading @dondi’s workflow for using pull requests to provide feedback to students, I wanted to try it this semester. I wasn’t exactly sure what steps were involved, but I found a workflow that worked for me and I wanted to share it. I decided that a screencast would be an easier way to illustrate the steps rather than trying to type every step.

In general, the key is to edit one of the student’s files (the edit is simply to provide an opportunity to comment in the pull request) so a branch and pull request can be created. At this point, comments can be left where each change was made.

In the past, I’ve provided feedback as comments via Canvas’ SpeedGrader. This new approach is much better in that the code on which I’m providing feedback is adjacent to the specific comment. Once students see that the assignment is marked complete in Canvas, they check the “feedback” pull request to review my comments. If they have questions or if they have answers to questions that I’ve asked, they can continue this conversation in the pull request. While this isn’t a traditional use for pull requests, it works well and it’s good for students to be familiar with participating in conversations for pull requests.

Please comment if you have any suggestions to improve this workflow or if you have any questions!

AP Physics B End-of-Year Survey Results

Before I start planning for the new AP Physics 2 class in detail, I first reviewed the end-of-year feedback from my AP Physics B students. I made very few changes in this course last year since two years ago went well and this is the last year for the course. In the following charts, a “1” represents strongly agree and a “5” represents strongly disagree.

A majority of the students didn’t read the textbook much. I’m not surprised by this since I don’t push the textbook very much. It is dated and doesn’t align much with my pedagogy. Students rely on other resources from class much more. However, I do think it is important that students learn to read a college-level text. I’m extremely pleased that next year we will have Knight’s College Physics text which I will incorporate much more strongly into the new AP Physics 2 course.

Screen Shot 2014 06 24 at 10 25 05 AM

I assigned conceptual questions from the textbook. Again, most students didn’t answer these. However, those that did, found them valuable. The conceptual questions assigned from the text were different than those I used for peer instruction. I may make use Knight’s conceptual questions as some of the peer instruction questions next year, which I expect will motivate students to answer them.

Screen Shot 2014 06 24 at 10 25 12 AM

Many students did not solve the homework problems. Those that did, found them helpful. Honestly, with few exceptions, I’m fine with this. I don’t grade homework and want students to learn to determine if they need the additional practice or not. Most of my students learn to self assess and make good choices in this area.

Screen Shot 2014 06 24 at 10 25 21 AM

Lab activities and practice quizzes are all about learning and not graded. Students found the quizzes (old AP free response questions) particularly useful. I’m really going to miss having a huge collection of old free response questions next year in AP Physics 2.

Screen Shot 2014 06 24 at 10 25 28 AM

I wanted to highlight peer instruction specifically. I was surprised last year how valuable students found peer instruction focused on conceptual questions. This year’s feedback was just as strong. In the free-form comments in the section “What are some things that I should keep doing next year?” peer instruction was mentioned more than anything else. I think focusing on conceptual questions through peer instruction will be even more important in the new AP Physics 1/2 courses which emphasize a deep, conceptual understanding. Perhaps, since this has been a focus of my class for the past two years, is why I’m freaking out much less than other AP physics teachers after taking the AP practice exams.

Screen Shot 2014 06 25 at 9 44 01 AM

Strong positive feedback on the summative labs for the course. I plan to incorporate those that are relevant into the AP Physics 2 course next year. We’ve already incorporated some of them into the AP Physics 1 course. The choices for the “I found the summative labs:” question ranged from too challenging (1) to too easy (5). In similar fashion to my AP Computer Science students’ feedback, students found the written feedback provided via Canvas helpful in developing their understanding of the material.

Screen Shot 2014 06 25 at 9 44 16 AM

A couple of surprises in terms of which labs students marked as their favorites. The Simple Harmonic Motion lab has students develop a mathematical model by modifying various physical characteristics of a mass on a vertical spring. I was surprised it wasn’t more popular. We also did this lab in Honors Physics (AP Physics 1) this year. I was surprised that the diffraction and interference lab was in the top 5. I don’t feel that it is one of my strongest labs, yet students disagree. No surprise that the capstone project was the run-away favorite. I will keep that in the AP Physics 2 class. I’m planning to continue to do the CMS Masterclass, which focuses on particle physics, in AP Physics 2 as well. Hopefully, we can do this as part of a field trip to Fermilab next year. We didn’t have a field trip to Fermilab this year. The most common suggestion in the section “What are some things that I should try next year?” was to have a field trip to Fermilab. I hate to lose the Projectile Motion lab. The only way it would be part of AP Physics 2 is if I use it as a lab for an introductory unit on computational modeling. It is too advanced for AP Physics 1 in the projectile motion unit.

Screen Shot 2014 06 24 at 10 26 23 AM

Pleased that so many students are considering pursuing STEM-related fields, but not too surprised since this is a second-year physics course.

Screen Shot 2014 06 24 at 10 26 30 AM

Strong positive feedback on standards-based assessment and reporting. Summative labs and exams were scored on a 1-5 scale. Each unit that consisted of one exam and one lab. I’m considering changing this next year and having a standard for each AP Physics 2 Essential Knowledge item grouped into categories based on each AP Physics 2 Big Ideas. I feel this will emphasize science practices and connections between concepts rather than my traditional approach focused on units and content.

Screen Shot 2014 06 24 at 10 26 35 AM

This summer I have a lot of work to do developing the new AP Physics 2 course which includes incorporating a new textbook and much more Modeling Instruction. I’ll take as much as possible from the AP Physics B course since most of it worked well the past two years. My AP Physics 2 students will also be piloting a 1:1 program (Chromebooks in the fall semester) which will require some additional preparation. AP Physics B is dead! Long live AP Physics 2!

AP Computer Science Reflections and Plans for Next Year

I’ve been collecting my thoughts on this past year throughout the summer. Since I’m about to start a new school year, now is a good time to review these reflections and share my thoughts and plans for the upcoming year.

Last year was the first time that I taught AP Computer Science. Based on my experience teaching Physics, I appreciated the significant difference between content knowledge and pedagogical content knowledge. I spent the year building my pedagogical content knowledge and trying various types of activities to determine which would be most effective. I expanded my network of computer science teachers throughout the year and attended a couple of great workshops this summer: the AP Annual Conference and the Tapestry Workshop.

One aspect of the class that did not work well was the textbook. The textbook was old (it didn’t cover Java 5 features) and didn’t align with my personal teaching preferences (I’m a strong object-oriented proponent and start objects first). We stopped using the textbook after the first couple chapters. My department chair was super supportive and I was able to purchase Cay Horstmann’s Java Concepts book for the upcoming year. I spent a lot of time this summer creating units, choosing questions, and selecting programming activities based on the new text, but it will be well worth it.

Students spent most of class time working on programming activities. These activities were small in scope, focused on a specific concept, and not graded. They were formative assessments. I spent most of class time visiting students, asking questions, and providing direction without being too helpful. Perhaps my favorite part of this class was that I had the opportunity almost every day to talk individually with every student and directly observe their work. This upcoming year, I hope to spend even more time on these programming assignments. I hope that with the better textbook, I can minimize lecture and notes and just focus on highlighting key aspects the assigned reading and discussing questions that the students have after having read the chapter.

One part of class that worked out very well, was providing choice in the programming activities. My students were fairly diverse in both interest and background knowledge. Providing them with a variety of programming assignments, all focused on the same concept, but of varying degrees of difficulty and application, allowed each student to challenge themselves and yet be successful. I stumbled upon this by accident when I was unable to decide which of three programming activities would be the best. I decided to offer all three and was surprised at increased level of interest as students chose their favorite. While I’m changing most of the programming assignments this upcoming year, I consciously defined sets of programming assignments to provide students with choice.

Related to these topics of choice and diversity, I quickly realized last year that some students would complete a programming assignment in 10 minutes while others would need an entire class period. Again, by accident or intuition, when I first encountered this diversity, I spontaneously created an extension of the programming activity to challenge student who finished quickly. After that, I made an effort to define extensions to most of the programming activities. I also encouraged students to explore their own extensions. I will offer some of these to this year’s class. Throughout the year, these extensions were generalized into the idea of “add more awesome.” As students finished the base assignment, they would start to “add more awesome” without direction.

While I’m changing most of the programming assignments, many of the summative programming labs will remain the same. The programming labs are submitted for scoring and involve significant effort compared to the programming assignments. We will continue to do the Game of Life lab, Media Computation, Fractal Trees, and Capstone projects. A few labs will be new. For example, we will try a Word Search lab from Stuyvesant High School.

There are a couple of new ideas that I found lacking last year that we will try this year. I want students to have more experience with Test Driven Development and unit testing with JUnit. I also want students to present their work to their peers; specifically, their capstone projects. While there was plenty of interaction among pairs of students last year, I didn’t provide an opportunity for students to present to all their peers.

My final focus for the upcoming year is applying some of what I learned at the Tapestry Workshop to increase the number of female students and under-represented minorities in computer science. Some of these efforts will be outside of class focused on administrators and counselors, but others will be in the classroom. Everything from my choice of programming activities to the decor of the lab can reduce stereotype threats. I hope to see a change in enrollment of the coming years!

Reflection and Refraction Activities

We are currently in the midst of the geometric optics unit in my honors physics class and just finished waves, which includes reflection and refraction, in my regular physics class.

My colleagues and I have developed a series of reflection and refraction activities that provide a shared experience that can be leveraged as we explore reflection and refraction of light. In addition, students find these activities engaging and they generate a lot of great questions.

I hope you find a new activity that you can use in class.

Here are the handouts.

Download (PDF, 41KB)

Download (PDF, 38KB)

I don’t have photos of the reflection activities, but I think they are pretty self explanatory. If not, ask, and I’ll clarify.

I do have photos of the refraction activities. I need to give credit for the first activity which is a recreation of an AAPT Photo Content winner from a few years ago.

Colored paper behind glasses

Colored Paper behind Water Glasses

Pencil in air oil water

Pencil in Air, Oil, and Water

Toy car in beaker 1

Toy Car in Round Beaker

Masses Hiding in Fish Tank (Total Internal Reflection)

N3L Activity Stations

While the Newton’s 1st Law activities serve as a fun and short introduction, the Newton’s 3rd Law activities provide a shared experience that spans several classes. The activities that the students explore are selected to highlight the most common preconceptions that students have about Newton’s 3rd Law. I stress how important free-body diagrams are as a tool in their physics toolbox and that, once they are adept at drawing free-body diagrams and once they actually trust their free-body diagrams, they will be able to explain a number of counter-intuitive situations. I introduce these activities by stating that Newton’s 3rd Law is one of the most easily recited laws of physics and yet is least understood. Here are the activities:

Download (PDF, 35KB)

Sequential Spring Scales

Sequential Spring Scales

The spring scales are initially hidden under the coffee filters. Only after students make their prediction are the coffee filters removed. Most students do not predict that the spring scales will read 10 N. Some predict 5 N (the spring scales split the weight). Some predict 20 N (10 N each way adds up to 20 N). In addition to drawing the free-body diagrams, this scenario can be explored further by asking students to predict the reading on the scales if one of the weights is removed and the string is tied to a clamp instead.

Bathroom Scale

This station provides an important shared experience that we will refer back to when discussing the elevator problems later in the unit. This station also generates a number of excellent questions such as “would the scale work on the moon?” and “how could you measure mass on unknown planet?”

Twist on Tug-of-War

tug-of-war

Students were very interested in this station this year since they were in the midst of Homecoming Week and inter-class tug-of-war competitions were being held. It may have been the first time free-body diagrams were used in the planning of the tug-of-war team’s strategy. The dynamics platform in the photo is a cart build from plywood and 2x4s with rollerblade wheels and has little friction. Most students claim that whoever wins the tug-of-war pulls harder on the rope than the person who loses. Only after drawing the free-body-digram and trusting it, do they realize this is not the case.

Medicine Ball Propulsion

Medicine Ball Propulsion

This is a fairly straight-forward station. I often wander by and ask the students exploring it why they don’t move backwards when playing catch under normal situations. I also check at this point and see if they are convinced that the force on the ball by them is equal to the force on them by the ball.

Computerized Force Comparison

This is the most important station in that it helps students truly appreciate Newton’s Third Law. I setup several of these stations to make sure that everyone has an opportunity to watch the graph in real-time as they pull on the force sensors. This is the standard Modeling activity for Newton’s 3rd Law. For students still struggling to accept Newton’s 3rd Law while working through this activity, I challenge them to find a way to pull on the two sensors such that the forces are not equal in magnitude and opposite in direction. This activity also counters the misconception promoted by some textbooks (perhaps unintentionally) that the “reaction” force follows the “action” force. Students can clearly see that both forces occur at the same time. (We refer to paired forces according to Newton’s 3rd Law, not action-reaction forces.)

WALL-E and the Fire Extinguisher

Who doesn’t love WALL-E? I repeatedly loop through a clip from the WALL-E trailer. In addition to the questions on the handout, I ask students what is incorrect about the physics in the scene. This year, I also showed students this clip that Physics Club filmed several weeks ago:

N1L Activity Stations

I like to introduce Newton’s First Law with a series of activity stations for students to explore followed by a couple of demos. They have fun and it provides shared experiences which we can refer back to later. Here is the activity sheet that guides them:

Download (PDF, 32KB)

Many of these stations and demos have as much to do with impulse as they do with Newton’s First Law. I mention this and we revisit these stations and demos later when studying impulse.

Most of these stations and demos are fairly self explanatory. However, a few can benefit from a photo. Here is the “Nuts about Hoops & Bottles” station:

nuts, hoop, bottle

You quickly grab the hoop with a fast, horizontal motion. This station can become overcrowded because some students obsess over trying to capture the most nuts in the bottle. (I’ve seen students catch over twenty.)

The “Hitting the Stake” station is perhaps the most surprising to students. It is easy to build and looks like this:

hitting the stake

The “Spin the Human” station works best on teachers with little hair. We have one constructed from pool balls. This one is built with golf balls and a coat hanger:

spin the human

It is best to put the “Chopping Blocks” station in the corner. Some students have an incredible amount of aggression to release.

I’m sure everyone has seen the “Clearing the Table” demo. If not, MythBusters has an extreme version.

A couple of years ago, I captured the “Egg Drop Soup” demo with the high-speed camera. I usually have all four eggs make it.

What is interesting about these activities is the evolution of this lesson. When I started teaching, these were all demos. I put on the show and the students’ engagement was that they laughed. A few years ago, my team transitioned these from demos to activities. More fun, more engaging. Based on a suggestion from my instructional coordinator, I now introduce each station and have the students record their predictions before get up and start visiting stations. This ensures they actually make predictions since many of these stations are too enticing for them to make predictions before playing with them.

Maybe I’ll let students “Clear the Table” next year.

CV Buggy Lab

Last week, I participated in a great discussion on Twitter about the various ways Modelers perform the Constant-Velocity Buggy Lab in their classrooms. The CV Buggy Lab is the paradigm lab for constant-velocity and, as a result, Modeling classrooms are filled with toy cars in the fall. I’m not sure why, but it seems that the red cars are always configured to go “fast” and the blue cars configured to go “slow”.1

CV buggies

We’ve always done a CV buggy lab, even before I started modeling, but this year we did something different. To provide some context, before we do the CV buggy lab, students have already completed a mini-modeling cycle involving the bouncing ball and explored non-linear relationships with the sliding box of mass and rubber bands. We have also briefly discussed the concept of position in terms of specifying the location of something relative to a commonly defined point. For example, “my chair is 5 floor tiles from the south wall and 10 floor tiles from the west wall.” Another teacher and I were discussing that since students were rocking these labs, our typical buggy lab that involves only one car might not be as engaging or beneficial. She decided to have students start with both cars from the start. I thought this was a great idea and decided that I also wanted each group to analyze a different scenario which would make the post-lab whiteboards discussion more interesting.

As a class, we go through the usual process of making observations, determining what we can measure, and, eventually, coming up with the purpose for the lab:

To graphically and mathematically model the relationship between position and time for two buggies traveling at different speeds.

At this point, I had to constrain the lab more than I usually would by specifying the starting position and direction for each car. I assigned each lab group a scenario (this allowed some degree of differentiation in terms of difficulty):

  1. red positive direction, blue negative direction; red at 0 m, blue at 2 m
  2. red positive direction, blue negative direction; red at -1 m, blue at 1 m
  3. red negative direction, blue positive direction; red at 2 m, blue at 0 m
  4. red positive direction, blue positive direction; red at 0 m, blue at 0.5 m
  5. red positive direction, blue positive direction; red at -1 m, blue at -0.5 m
  6. red negative direction, blue negative direction; red at 2 m, blue at 1.5 m

Their homework was to draw a picture of their scenario and brainstorm on how they would design the experiment.

The next day, groups designed their experiment. I didn’t provide any additional restrictions. I only verified that their pictures matched the scenarios that I had specified. Some groups decided that their independent variable would be time; others, position; others, distance. One group decided to gather data from both cars at the same time! Another group taped a marker to the back of the cars which traced their paths on butcher paper and allowed them to make more accurate measurements of the actual distance traveled.

When groups started graphing their data, I requested that they plot time on the horizontal axis. Some objected and remarked that if time was their dependent variable it should be plotted on the vertical axis. I explained that I wanted all the groups to be able to share their results which would be easier if we used a common set of axes. I reassured them that the graph police would not come and get them for plotting their dependent variable on the horizontal axis. (Anyone know why this is the convention?)

Some expected and unexpected issues emerged as students began to graph their data. As expected, those groups who chose to measure distance instead of position soon realized that their graph wasn’t going to convey everything they wanted. They went back, and using their picture, calculated positions corresponding to each distance. We use LoggerPro for graphing, and those groups who made time their independent variable, simply added a new column for the position of the second buggy. LoggerPro makes it super simple to graph multiple sets of values on the vertical axis (click on the vertical axis label and choose Moreā€¦). However, those groups that made position their independent variable had more trouble since LoggerPro only allows one column to be plotted on the horizontal axis. These groups required more assistance and, in the end, I discovered that it was best to create two data sets and name the time columns identically for each. LoggerPro would then plot this “common” time column on the horizontal axis and the two position columns on the vertical axis. Not super simple, but doable.

2 data sets in LoggerPro

Each group drew their picture, graph, and equations on a whiteboard. We did a “circle whiteboard” discussion rather than having each group formally present their results. At first, the discussion focused on how the graph described the motion of the buggies. As students became more comfortable with those ideas, the discussion shifted to comparing and contrasting the different whiteboards. This was the best whiteboard discussion for the CV Buggy Lab that I have ever had. At the end of class, I confidently shared that their whiteboards captured everything that we would learn about constant velocity. We just needed more time to digest, appreciate, and refine what they had already created.

I’ll definitely do this again next year, but I hope to find a way to not assign each group a scenario and yet still end up with a variety of initial positions, directions, and relative motion. Perhaps, if I ask each group to design their own scenario, I can subtly encourage small changes to ensure the variety still exists. Plus, students usually create scenarios that I never would consider!

1 There are many ways to make the blue buggy slow. I have used wooden dowels wrapped in aluminum foil and wooden dowels with thumbtacks and wire. Others have shared that they use dead batteries, electrical tape, and aluminum foil. This year, I tried something completely different. I found these wires with magnetic ends while cleaning last spring (I have no idea who sells them). While in previous years, it seems that in every class someone’s blue buggy has an intermittent connection, I had no problems at all this year.

making a slow car