"Conservation of Momentum" in a Transition to Physics First

Two teachers at the same school facilitate essentially the same lab activity, but with different levels of commitment to the process of inquiry.

In a time of transition from a traditional BCP sequence to a Physics First sequence, schools or districts are often faced with a distinct challenge of limited personnel. A ninth grade physics class is fundamentally different from both a ninth grade biology class or a physics class directed toward juniors or seniors, and very few teachers have direct experience teaching Physics First. In the switch to ninth grade Active Physics in the San Diego public schools, for example, the transition was driven mostly from the top down, with grossly inadequate professional development to prepare teachers for the task they were undertaking. Many biology teachers were simply ordered to become physics teachers, and physics teachers who had no experience with younger students were dropped into a project-based curriculum with little quantitative emphasis. The program was doomed to fail from the beginning, and San Diego switched back to BCP five years later.

Much of the time, however, the remnants of a switch to Physics First can be more more subtle. I visited a public school near Philadelphia that offers a Physics First track as an option for high-achieving students. The majority of ninth graders take environmental science. During my visit, I saw observed two sections of physics for ninth graders, both based in Modeling Instruction but taught by different teachers. The same basic lab activity was carried out in each class - both labs involved the use of a track with two carts with photogates mounted to measure the speed of a cart rolling toward either end of the track - but there were important differences between the classes.

At the beginning of one class, the teacher wrote a simple prompt on the board: "Objective: graph ∆Pbluecar vs. ∆Predcar" and showed students examples of possible interactions between the carts (bouncing, sticking, etc.). Students set to work putting together the apparatus, making measurements, calculating values, and eventually, plotting these values on a set of axes.

In the other class, the teacher gave students a worksheet on which to record the results of three specific collisions (bouncing with both carts moving toward each other, bouncing with one cart still, and sticking with one cart still). After all students had completed the required calculations for each collision, he asked students to tell him the results of their collisions and wrote each group's result on the board. He then told students:, "Something needs to be true about those initial and final momentums. If you didn't get this, there will be a lot of things wrong when I correct this lab... This is the goal for this unit." The teacher then wrote "pi = pf" on the board, and explained the details of conservation of momentum to his students while they sat in their seats.
 
Both of these classes served as the introduction to the same Modeling-centered unit on conservation of momentum, yet it seems to me that only one of them held true to the priorities of inquiry-based instruction. It's relevant that the first class was taught by a teacher whose Modeling Instruction training came early in his physics teaching career, while the second was taught by a seasoned physics teacher with many years of experience teaching AP. I learned in talking to this second teacher that the science faculty were a major force behind the decision to choose Modeling Instruction as a curriculum for their Physics First classes, but (on the basis of this one brief observation) the Modeling training they both received impacted the younger teacher more deeply than the older teacher.

At the end of my visit, I spoke with another teacher at the school who is teaching a "Pre-Chem" course for lower-track students, consisting of three units of Modeling chemistry combined with a less-quantitative introduction to five units of Modeling physics. (This teacher is also a Modeling Instruction summer workshop leader.) We talked about the complexities of transforming one's own teaching style, and the role that various teachers have played in the broader transition to Modeling at this school. It's clear that a successful transition to Physics First requires strong administrative support, but administrative support is no help at all if the teachers themselves are not committed to the classes they are teaching. Perhaps the successes of the program at this school are due in part to the flexibility of everyone involved to adapt to a wide range of teaching styles and expectations through this transitional period.

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Creativity and Introductory Physics

Open-ended, "creative" assignments can be an effective way of making science relevant to students, but there are more direct ways to exercise the creativity needed to excel in the fields of science and engineering.

"Creativity and Introductory Physics" is the title of an essay in the January, 2012 issue of The Physics Teacher on the importance of giving physics students opportunities for creative, divergent thinking (page 42 if you've got it handy).  In the essay, the author, a professor at Union University in Jackson, TN, illustrates how he tries to incorporate creative assignments into his courses, in topics ranging from magnetism to wave-particle duality. The teacher offers an example of a creative assignment where students are given an option to "create an original story that is critically dependent upon the concepts of Einstein's special theory of relativity," among other options.

For some students, assignments like these can bring seemingly irrelevant and abstract ideas into focus. In a general interest course about the weird world of modern physics offered at my alma mater, the final project for the course was quite similar in nature to this one, and I knew many humanities folks who expressed relief that they could receive "quantitative proficiency" credit for writing a poem about the impossibility of faster-than-light travel! But such assignments can sometimes bear only superficial relevance to the physics being studied, and I believe there are applications for creative thinking that more directly exercise the creativity that is essential for being a good scientist. One example is the student-designed paradigm labs that form the introduction to most units in a Modeling Instruction course. Another is the requirement of "Design Criterion" labs in the IB Physics Internal Assessment, where students must develop an investigation into the relationship between two variables of their choosing. (One student of mine investigated the relationship between the mass of iron filings mixed into a consistent sample of play-doh and the resistance of the dough. Another looked at the relationship between the time a spaghetti strand was left soaking in cold water and the applied force from a spring scale required to break that strand... One written example of such a project can be found here.)

In this short excerpt from a talk given by Sir Ken Robinson on divergent thinking and creativity, we learn that an individual score on some quantitative evaluation of divergent thinking generally declines drastically from age 3 to age 25:

I'd love it if Robinson gave us a few more details about this test (he refers to a book called "Breakpoint and Beyond" - I'll let you know if I end up picking it up), but this little result tells us exactly what we should be fighting in our physics classes - as our students get told how things work, they learn to see fewer possibilities in the world around them, to look outside themselves for ideas. I can't think of a better argument for teaching physics in ninth grade! Ninth graders are enthusiastic and creative thinkers, potentially unburdened (in some environments) of the pressures of getting the answer right as quickly as possible so that they can move on to the next question. What better time than early high school to reinforce to our students that science is something that is done with your own two hands?  What better tools to accomplish this than tangible instruments like the meter stick, the stopwatch, and the spring scale? (and the force plate, and the motion detector, and the video camera...)

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Yale-Lynn Hall Teacher Action Research Prize

A quick one: A friend of mine just let me know about an informal PER project that won an interesting prize in March of last year: the Yale-Lynn Hall Teacher Action Research Prize. It's timely only because the deadline for projects this year is coming up in early February. One of the winners of the $1000 prize last year was a teacher at Camden Hills Regional High School in Rockport, Maine. She carried out an investigation into the effect of in-class personal response systems, or clickers, on student FCI scores and AP-C Mechanics scores. So get your research in by February 3!!

This particular paper can be downloaded and read here. The results of the investigation reveal that although the increase in FCI scores was not statistically significant (an increase in the averaged normalized gain from 0.465 to 0.475), there was a significant increase in scores on the multiple choice section of the AP-C. Notably, the teacher identified a dramatic improvement in student affect toward class discussions of multiple choice problems. "Students seemed more engaged and invested in discussing their ideas about physics when the subject of that discussion [involved the use of clickers]."

Though PER is thriving in universities across the country, there continues to be very little direct research into the efficacy of Physics First. Developing a controlled study of the effect of a given method in a high school is challenging, given small sample sizes and wide variations in factors affecting student performance. Perhaps a research prize targeted specifically for ninth grade physics teachers could encourage teachers to investigate the impact that their own classes have on local populations.

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Modeling Workshop and Revising Worksheets

This past summer I had the opportunity to attend one week of a three-week workshop in a physics teaching method known as Modeling Instruction. The workshop was a couple hours drive away, and I got a flat tire on the way down AND the way back (!!), but it was well worth it. The leader of the workshop knew Modeling inside and out, and graciously filled me in on some details about the weeks that I was missing. I probably wouldn't try to teach a Modeling course without attending the full three-week workshop, but this was a perfect introduction to whet my appetite for learning more about the method. I took so much away from the workshop I'll have to spread it out over multiple posts, but here are some thoughts I've been having in the meantime...

I've seen a few Physics First classes where Modeling is used, and all of them have used worksheets that are centered around solving classic quantitative problems (projectile motion problems, collisions, etc.). Most of these worksheets were developed a few years ago, out of the Modeling Instruction Program at Arizona State University. Many of these worksheets can be found on various websites, if you hunt around a bit, but the Modeling Instruction Program has taken pains to prevent them from being disseminated freely. On their own, the worksheets are a somewhat misleading "face" for the Modeling method, and the important aspects of Modeling as a curriculum are not in contained in these worksheets. However, when a physics teacher looks around for documentation about how to teach a Modeling class, these worksheets are often what they see. In fact, I've talked to teachers who use these worksheets as problems sets in their class, but lecture to their students in an otherwise totally conventional way. These teachers are missing the point of what makes Modeling special.

I've felt for a while that these worksheets do not reflect my own priorities for what should be emphasized in a course for ninth graders. Some are overly quantitative for the math level of many freshmen, and they do not overtly provide fuel for "conceptual" discussion. Let me clarify: a good teacher of Modeling can definitely emphasize the aspects of a problem that would be considered conceptual, but these aspects are not often emphasized in a given worksheet itself. But these particular worksheets do not have to be the worksheets used in a Modeling-based Physics First class. I feel that there is a lot of exciting work yet to be done developing curriculum materials to apply Modeling Instruction to a ninth grade level.

Some teachers in various parts of the country have taken on the task of revising these worksheets to be more age-appropriate for fourteen-year-olds. In particular, a password-protected page on the ASU Modeling Instruction site offers two sets of materials developed by teachers at at high school in Missouri and another in Pennsylvania. I've just started to look through these modified worksheets, but what I've seen is very exciting. You can get an idea of how the class works by checking out some of the whiteboards posted on one of these authors' page of whiteboards prepared by students in his Honors Freshman Physics class.  Unlike the worksheets mentioned above, whiteboarding IS central to the Modeling method - you can see some whiteboarding in action here.

I'm curious to what extent other teachers have undertaken their own attempts to "freshmanize" the modeling materials. Teachers new to the method may not feel experienced enough take on the task of making new worksheets themselves, and veteran modelers have probably developed effective ways to steer worksheet discussions where they'd like to go through class discussion. I have started to work out how materials I developed for my own class would fit into a modeling course, but I've only gotten so far… Perhaps, not too long from now, revised worksheets such as this will form the core of more Modeling workshops geared specifically for teachers of Physics First, and the Modeling materials that get used in ninth grade classes across the country will begin to shift.

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Happy Holidays, and THANKS to the Physics First listserv!

Happy Holidays! It's been a while since I posted last, and I apologize... I've been busy with some other things, including a nation-wide tour with a rock band that I've played in for a about 10 years now!! Here's a music video I made for one of our songs, in a case you'd like to check it out!! (If you look closely, you'll see a demonstration of blackbody radiation from a light bulb AND a glowing piece of 0.7mm mechanical pencil lead - it's amazing what 6A can do!!) In any case, sorry for the delay... I've got a lot to catch up on, so let's get started!

In the spring of last year, I had an opportunity to sit in on a few classes taught by a teacher who has been a great asset to the movement to popularize Physics First. This teacher maintains the Physics First listserv, an invaluable resource to all of us interested in seeing Physics First gain traction across the country. Many of the teachers I've observed for this blog I've found through the listserv. For as long as I've known about Physics First the listserv has consistently been a great hub of communication for educators and physics education researchers across the country, and even the world.

The school I visited is a Quaker boarding school in Pennsylvania, on a beautiful campus surrounded by trees and open fields. I spent the better part of the day at the school, and sat in on quite a few different physics classes, as well as the school's weekly Quaker meeting. This teacher's teaching style was relaxed and comfortable, and students clearly felt at ease. They were studying wave motion, and after a few minutes of lecture on the topic, the entire class headed outdoors to measure the speed of wave pulses on large slinkies that the teacher had affixed to trees earlier in the day. When we returned to the room, I polled students (at his suggestion) with a simple prompt, to be answered anonymously: "Name three things that come to your mind when you think of this class." The students were honest, and the responses showed varied levels enthusiasm ("interesting concepts", "learning how things work", "too much math"), but taken together this poll was a nice window into the success of the Physics First program at this school.

In conversations with this teacher during my visit, I learned that last year was his final year of teaching. He had been at the school for decades, and has seen the Physics First program grow from its initial implementation in 1999. In my brief time at the school, I saw this teacher offer his time and experience to teachers and students time and time again - even giving up his free periods to help another teacher run the same waves on slinkies lab he had prepared earlier for his own class. This teacher had a presence at the school that will be sorely missed, and his ongoing contributions to the Physics First community are much appreciated.

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Discussion Physics

This is a very exciting day for me because the September issue of The Physics Teacher came in the mail... Most exciting of all, a column I wrote on using handouts to teach effective note-taking in my ninth-grade physics class is printed in this issue! If you're a subscriber to The Physics Teacher, the column is on page 396 of Issue Number 6 of Volume 49, or you can read it here. If you're not a subscriber, you should be!! (You can subscribe to TPT here.)

The "For the New Teacher" column, organized by Patricia Blanton of Watauga High School, is intended to provide helpful tips for anyone new to physics teaching, and to help all physics teachers expand their thinking to include creative new methods. My column suggests a way to use Notes Outline handouts to provide a hierarchical structure to help students think about new concepts and methods in their science class, and be aware of how these concepts are presented over the course of a class discussion. Here is an excerpt from the column: 

Taking conscientious notes in a science class is a skill that's crucial for a student's success, yet students rarely receive direct instruction on how to do this... A sophisticated note taker must simultaneously recognize the role of new ideas and examples in the hierarchy of information of the class, and identify which pieces of information will be most valuable to have recorded... In my Notes Outline handouts... [questions that will be the focus of class discussion] are highlighted in sections marked Notes on Discussion... Students are expected to [record any arguments or examples from this discussion] that will help them answer a similar question later on... Isolating the most sophisticated and personalized form of note taking in these Notes on Discussion sections allows students to focus on and practice this technique specifically.

One aspect of these Notes on Discussion sections that I did not elaborate on in this column was the role they play in the labs that I've written for use in my course. Taking a cue from the fantastic Physics by Inquiry books, (by Lillian C. McDermott and the Physics Education Group at the University of Washington) I like to structure student discussion of a complicated idea by offering excerpts from a discussion on this topic between fictional students.

Here is an example of how Physics by Inquiry structures a student discussion about batteries and bulbs:

Consider the following dispute between two students.Student 1: "The current through the battery in each circuit is the same. In the circuit on the right the current from the battery is divided between the two bulbs - so each bulb has half the current through it that the bulb in the circuit on the left has through it."

Student 2: "We know that the current through each of the bulbs in the circuit on the right is the same as through the bulb in the circuit on the left. That's because the bulbs are all about the same brightness - and bulbs that are equally bright have the same current through them. So the flow through the battery in the circuit on the right is more than through the battery in the circuit on the left."

Do you agree with Student 1 or Student 2?

(Physics by Inquiry Vol II, McDermott & P.E.G., 1996)

I fell in love with this method of structuring lab discussions the moment I first saw it. Giving words to common student misconceptions is an excellent way to bring these misconceptions out into the open so that students must face the concrete implications of such thinking directly. I have found that asking a complicated question outright in a lab handout is ineffective, as students' responses are often brief, hasty, and poorly thought through. With the structure of a fictional discussion, however, students will often collectively reach a correct conclusion through discussion in their lab group, even if no individual student could clarify a correct response on their own. Furthermore, these passages from fictional students provide opportunities to model effective argumentation in science - emphasizing for students the importance of supporting claims with data and defending the relevance of these data as evidence of the claim.

In my labs, the Notes on Discussion prompts remind students that they have a responsibility during lab not only are they expected to participate in these discussion, but they must also record whatever they'll need to recall the details of this discussion later on when they look back over their lab notes. I've posted an example of a lab on Newton's Third Law that uses these Notes on Discussion prompts extensively here. I like this example because it demonstrates how Notes on Discussion can be used to structure both discussions within small lab groups and discussions that include input from the entire class. I have started to make some handouts that I developed for use in my own class available on the web here, but this project is far from finished. You are welcome to use anything you find on this page in your own class, but please write me an email to tell me that you're using it, and please give me feedback on how these resources worked for you.

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When a Mile Wide is Too Wide...

All physics teachers make choices concerning the depth and breadth of material they include in their courses. Physics First is a golden opportunity to establish a new paradigm of priorities for our students that is informed by recent developments in education research and PER.

In May of this past school year, I visited a public school in New Jersey that made the switch to Physics First about five years ago. The impetus for the switch initially came from the district superintendent, as a way to increase student scores on the state Biology test. (Though the state does not require students to pass the bio test to graduate, this particular test is held up as evidence that a school's science program is successful.) This reasoning is increasingly a driving force behind the switch to Physics First in many schools throughout New Jersey and beyond, as administrators notice how much better Juniors at PCB-sequenced schools (physics first, then chemistry, then biology) perform on a Biology test than Freshmen at BCP-sequenced schools. Though it's easy to question the merit of this rationale, the fact remains that Physics First is coming to more and more public schools for this reason. With it comes a great opportunity to teach an excellent introduction to the natural world and to the discipline of science.

The Physics First classes that I sat in on at this school were fairly typical of a traditional physics class: most sections were studying waves, and I saw diagrams of first, second, and third harmonics for standing waves on a string drawn on the whiteboard next to similar-looking diagrams for standing waves in open and closed tubes* (along with the ubiquitous and tautological λ=v/ƒ). An accelerated section was working under a different yearly sequence, and students were carrying out a lab on projectile motion in which they they attempted to place a target on the ground to predict where a projected ball would land. The teacher carried out the correct procedure for collecting the necessary data and making the necessary calculations, and then turned students loose to carry out these steps on their own.

A teacher new to the school revealed that a colleague who'd been teaching the Physics First class for a while already instructed him that the best way to teach physics to ninth graders was "a foot deep and a mile wide." This indicates a prioritization of content knowledge over critical thinking skills and, unfortunately, I have gotten the impression that this attitude is all too common among high school physics teachers.

A physics class taught in ninth grade has a great luxury over many physics classes taught in other grades in that standardized tests in physics for ninth graders have not (yet) gained popularity. An institution usually has to show indications that students have shown academic progress as a result of taking a Physics First course, but how the school chooses to measure these gains is often more flexible than for, say, a ninth grade Biology class. If a school wants to show that their Physics First class teaches students to think about science like a scientist, Lawson's Classroom Test of Scientific Reasoning can be used, and if a school prioritizes teaching students to internalize "Newtonian thinking," the most recent edition of the FCI (revised to be ninth-grader-friendly) can be used as well.

Given such an opportunity to emphasize scientific thinking and fundamental conceptual understanding, I'd love to think that "mile wide" breadth of content in Physics First would be our last concern. Does a student benefit from being exposed briefly to diagrams of both standing waves on strings and standing waves in tubes, when one diagram so often reinforces misconceptions about the other? Why would we ask our students to spend a lab period carrying out a prescribed procedure for solving a projectile motion problem when they could spend the same time designing and carrying out their own method of isolating variables and collecting data in a simple investigative experiment?Physics First is by no means a "silver bullet" solution to our science-teaching struggles . Rather, it is a golden opportunity: a chance to establish a new set of priorities for students that will impact their relationship to science throughout their lives, rather than asking them to perform the same old number crunching and regurgitation of bullet points.

*This has always frustrated me!! A very high level of abstract and sophisticated thinking is required to interpret the physical phenomenon that is represented by the "pressure vs. position" or "displacement vs. position" graphs (shown below) often presented during a study of standing waves. That these graphs look conveniently similar to the observable shape of a standing wave on a string only makes this more difficult to understand.
Here is an example of a conversation I had with a rather bright student while visiting another ninth grade class doing a lab on standing waves using tuning forks and glass tubes:

Me: So, what's going on in this tube?

Student: The air comes down the tube, bounces off the bottom, and then comes back up.

Me: How do you explain why these diagrams show two different lines for the air?Student: Those are the paths the air takes down the tube and then back, or... I guess that maybe the two prongs of the tuning fork would each make their own stream and then cross in the middle?

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