Jan 30, 2012

Active Physics and Inquiry

An independent school in New York City provides an excellent example of a successful application of the Active Physics curriculum, but aspects of Modeling Instruction could have potential to make the course even more dynamic.

Active Physics is a project-based curriculum with a conceptual focus, designed to be used with ninth graders. Active Physics groups concepts by themes, such as "Communication," "Sports," or "Home," in an attempt to make the physics more relevant to students' daily life. The work done in each unit culminates in a "Chapter Challenge," where students must apply their knowledge to solve a real-life problem. One independent school in New York City has been using the Active Physics curriculum since 1994 as the foundation of a physics course for all ninth graders. When I visited this school, students were studying the efficiency of various methods of heating water, and were just about to begin the "Chapter Challenge" of selecting appliances to meet the basic needs of an average family, capable of being powered by wind-generator with an output of only 2400W.

When class began, students were seated in lab groups, discussing a question from their textbook: "Are high-efficiency appliance worth the added cost?" Students' responses reflected a common misconception - conflating the efficiency of an appliance with an assessment of its overall quality: "Well, yeah they're worth it... they're better." "They're more durable, work faster, and just work better in general." When students were asked to present the results of their discussion, only one group in three appreciated the more subtle implications of the concept of efficiency, stating, "A higher efficiency appliance will make up for its cost with less power used over time," but even this group was confused by the difference between the terms "power" and "energy." The stage was set for an inquiry-based activity to root out the would root out these misconceptions and lead students to a more sophisticated understanding of the concepts of energy, power, and efficiency.

The lab activity for the day consisted of heating up a beaker of water on a hotplate. The procedure steps outlined in their textbook were summarized on a projector: "Measure: 150mL of water, initial and final temp of water, measure time appliance is on (increase temperature by 20˚C)." After a brief discussion of how to use the equipment, students got to work carrying out these steps. They made a few potentially problematic procedural choices along the way (measuring water volume with a beaker rather than a graduated cylinder, plugging in the hotplate before starting their stopwatch, resting the thermometer against the bottom of the beaker, for example), but the teacher caught most of these and gave suggestions for improvements when he felt it was necessary to do so. In class discussion, students struggled with how to use the values they'd measured to make the required calculation of efficiency, but the teacher coached them through the process (partly by referring them to a similar activity done a few days earlier with immersion heaters):

Teacher: "Who remembers how we calculate the thermal energy gained by the water?"

Student: "Was that the thing that was 4.18...?"

Teacher: "Yes, we need the specific heat of water. Anything else?"

Over the course of the discussion, each group eventually arrived at calculations that basically agreed with one another, confirming an efficiency of about 10%.

While watching students carry out this activity and discuss the correct method for calculating efficiency, I tried to imagine what the same basic procedure would look like using a whiteboarding approach. Students might start the lab by brainstorming steps they'd take to to collect whatever data they felt were relevant to a calculation of efficiency, then writing these steps on a whiteboard and presenting them to the class for discussion. Once students had carried out these steps with their lab group, they could attempt a calculation of efficiency (again, on a whiteboard), and discuss as a class whether the calculations they'd made were relevant to the central question of the efficiency of appliances. Different groups could even use different methods of heating the water: an immersion heater, a hotplate, a microwave...

I emailed a prominent advocate of Modeling Instruction to ask about crossover between Active Physics and Modeling Instruction, and she told me that "Active Physics and Modeling Instruction don't go well together." Modeling Instruction is about developing basic models for the most fundamental interactions in physics, whereas the projects in Active Physics tend to highlight more complex applications of these concepts: efficiency of electric appliances, acoustic properties of instruments (watch your ears...), how to build a DC motor or generator, etc. Both of these approaches have merit, and it seems to me that there's a lot to be gained in exposing students to aspects of both. That is, a whiteboarding approach might have avoided the more "cookie-cutter" aspects of this particular lab activity on heating water (and probably brought misconceptions to the forefront more effectively), and a project-based "Chapter Challenge" in a Modeling course might give students a better appreciation for how even the simplest models they develop can be applied to their daily life.

In my observations, I've noticed a trend among teachers of Physics First: in the absence of a single universally-accepted ninth grade physics curriculum, teachers tend to pick and choose aspects of various programs that appeal to them. This dynamism is healthy and exciting, but there is something particularly thrilling about the momentum that has been building around Modeling Instruction. A lot of aspects of Modeling just feel like the right way to teach physics: whiteboarding, student-designed experiments, modeling phenomena with multiple representations, and it's tremendous to see the Physics First movement marching forward hand-in-hand with Modeling Instruction. Still, we'd be wise to keep in mind the potential benefits of a diversity of approaches and try to maintain some of the freedom and flexibility that characterizes so many ninth grade physics classrooms.

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Jan 24, 2012

Colleague Response to a PF Inquiry on the Scarcity of PF Research

I get teased by some friends about it, but I'm a very proud member of a couple of physics teacher clubs. In one, around 20 or so individuals meet monthly to discuss experiences in physics teaching and share ideas. Recently, a teacher wrote to this group to inquire about teachers' experience with Physics First, and a friend in the group named Yoav Bergner wrote a response that very eloquently gets at the heart of some of the questions about its effectiveness. Yoav is a former educator, and is currently an education post-doc in the ReLATE program at MIT (as well as a builder of fine furniture and a fellow education blogger). He gave me permission to post his response here... and to include this photo of the phenomenally beautiful Ms. Pacman butcher block he made as wedding gift for a friend!

Now, this blog isn't usually a venue for major criticisms of Physics First (I'm such a fan of the movement after all, did you know?). Yoav's response contains a lot of different viewpoints and opinions on PF, and a few of these positions don't match my own personal opinion. But one major point that Yoav makes is hands-down irrefutable: there's just not enough research yet done to show that a PCB sequence is more effective, on average, than a traditional sequence. Anecdotal evidence shows plenty of success stories, and indeed plenty of failures as well, but hard numbers for or against are scarce. I'd add to that, though, that "more effective" can mean a lot of things: FCI gains, Lawson's reasoning test gains, increased enrollment in a higher-level physics course, increased student affect toward science, or even simply (as Yoav himself mentions below) the number of students who end up taking a physics class at least once in their lives. Teachers and researchers across the country have been responding to this need with research of their own since back in 2003 when Pasero's State of Physics-First Programs was published, and I know personally of a few programs and schools with data that are just around the corner.

Anyway I apologize for the interjection... Yoav's words from here on out (citations below):

The Physics First argument is often made unduly complex; there may not be much to it beyond the desire to increase the enrollment of high school students in physics. Neuschatz and McFarling attribute poor performance by the United States on the TIMSS to the limited reach of physics, arguing that, “our prime shortcoming is not the poor job that is done when physics is taught, but rather the fact that so few students take it, and that fewer still get beyond the basic introduction” (Neuschatz). Other defenses for inverting the traditional sequence, such as the claim that chemistry and subsequently biology build on concepts from physics, are countered by the traditionalist’s view that physics simply requires more mathematical sophistication. But math prerequisites have subsequently excluded many students from taking physics at all. Exposing “the largest number of people” to the “broadest range of physics topics” might be viewed as reason enough for teaching physics in ninth grade (Bessin).

While there is not widespread agreement that Physics First is a good idea, there is a general consensus that if it is to be adopted at all, a ninth grade physics course should be conceptual and should not focus on mathematical problem solving. This was hinted at in Lederman’s Physics First advocacy writings, in which it is recommended that mechanics, for example, be de-emphasized (Lederman, 1998). The idea is explicit in the AAPT report, “the emphasis in a physics-first sequence should be on conceptual understanding rather than mathematical manipulation,” but the rationale is perhaps best articulated by Hobson and also Hewitt. Hobson’s point of view is that a first physics course should address societal needs for conceptual understanding of modern issues, that mathematical problem-solving is appropriate for a second course. A first course should expose students to exciting topics: quantum physics, cosmology, global warming, pseudoscience, nuclear weapons (Hobson, 2005; Hobson, 2006). He cautions that “many physics teachers resist teaching conceptual physics for all. If we insist on teaching a math-based course first, we will continue turning away both science and non-science students in droves, and it will be essentially impossible to institute physics first” (Hobson, 2003).

Hewitt is a well-known proponent of conceptual physics via his classic textbook, which has been in print since 1971 and is used in the vast majority of physics courses aimed at non scientists. In 1982, he opined, “I think most teachers feel that the conceptual and traditional can be taught simultaneously. I think not, and will exaggerate to make my point. I suggest that teaching conceptual and traditional physics together is akin to teaching children to dance during the stage of life when they'd normally be learning to walk” (Hewitt). Recently, Goodman and Etkina have hinted at a successful “mathematically rigorous physics first course,” but their claims need to be scrutinized in the context of the following: at the school under study, the physics class is designed to mimic the content and structure of the AP Physics B test as much as possible; the full course material is spread out over two years of physics (second year optional); the only assessment is performance on the AP Physics B; and only 20% of graduating seniors end up taking the test (Goodman).

The sad reality is that there are almost no real data showing measurable success or failure in the Physics First effort. Dozens of articles and letters published in The Physics Teacher make claims with barely a shred of support (for example, Dreon, Ewald, Korsunsky, Taylor); meanwhile the San Diego school system experienced a rejection of the new curriculum by some affluent districts, which were subsequently granted academic independence to return to traditional sequences (Tomsho). There is scant evidence that decades of physics education research are being applied in Physics First programs––high school teachers are not by and large documenting their progress. There is scant evidence that decades of physics education research are being applied in Physics First programs––high school teachers are not by and large documenting their progress. Pasero’s 2001-2003 ARISE report on the state of Physics First programs acknowledges the following points (quotes due to Pasero, enumeration mine):

1. “Teaching a math-free physics course [is] very difficult,” Pasero observes, noting further that schools typically select one of the following strategies to deal with math-related challenges: (a) make algebra prerequisite, (b) offer two tracks, or (c) coordinate physics and algebra courses. “Negative comments [from students] were almost exclusively reserved for times when they felt the math was overwhelming.”

2. “Students’ favorite part of physics class was labs.”

3. “This may be the most significant finding of this study: Physics-first schools are not quantitatively documenting the degree of their success.”

American Association of Physics Teachers (AAPT 2006). “Physics First: An Informational Guide for Teachers, School Administrators, Parents, Scientists, and the Public”.

American Institute of Physics. Teaching Physics First

Bessin, B. (2007, March). “Why Physics First?” Guest Editorial, The Physics Teacher 45, 134.

Dreon, O. (2006, Nov). “A Study of Physics First Curricula in Pennsylvania”, The Physics Teacher 44, 521-523.

Ewald, G., Hickman, J., Hickman P, and Myers, F. (2005, May). “Physics First: The Right-Side- Up Science Sequence,” The Physics Teacher 43, 319-320.

Goodman, R. and Etkina, E. (2008, April). “Squaring the Circle: A Mathematically Rigorous Physics First,” The Physics Teacher, 46, 222-227.

Hewitt, P. (1983). “Millikan Lecture 1982: The missing essential––a conceptual understanding of physics,” Am. J. Phys. 51 (4), 305-311.

Hobson, A. (2003, Dec). Letter to the Editor, The Physics Teacher 41, 508-509.

Hobson, A. (2005, Nov). Letter to the Editor, The Physics Teacher 43, 485.

Hobson, A. (2006). “Millikan Lecture 2006: Physics for All,” Am. J. Phys. 74 (12), 1048-1054.

Korsunsky, B. and Agar, O. (2008), “Physics First? Survey First,” The Physics Teacher 46, 15-18.

Lederman, L. (1998). “ARISE: American Renaissance in Science Education,” Fermilab-TM- 2051.

Lederman, L. (2005), “Physics First?” Guest Editorial, The Physics Teacher 43, 6-7.

Neuschatz, M. and McFarling, M. (1999). “Maintaining Momentum: High School Physics for a New Millennium,” AIP Report R-42.

Pasero, S. (2003). “The State of Physics-First Programs”, Revised March 2003, Fermilab-Pub-01/206.

Sheppard, K. and Robbins, D. (2002) "Physics was once first and was once for all" The Physics Teacher  41, 420.

Taylor, J. et al. (2005). “Curriculum Reform and Professional Development in San Diego City Schools,” The Physics Teacher 43, 102-106.

Tomsho, R. (2006, April 13). “Textbook Battle: Top High Schools Fight New Science as Overly Simplistic”, The Wall Street Journal.
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Jan 19, 2012

"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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Jan 12, 2012

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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Jan 11, 2012

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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