Physics and Physiology

Physics and Physiology

Design and Testing of Physics and Physiology: An Early High School Science Program.

Bones and Fractures:

A common theme in physiology is that form follows function. The way something looks and how it is built is a reflection of the job it has in the body. Students in the Physics and Physiology classroom explore bone physiology by examining strength of different materials and taking what they know to build models of long bones. They take density measurements and subject their models to different forms of stress: compression, tension, torsion, and shear, and compare the subsequent fractures to x-rays of actual bone fractures. The materials making up the weakest and strongest models are compared to those materials making up actual bones. In this way, students develop a more complete understanding of skeletal functional morphology, as well as force and strain.

The Physics and Physiology project is an initiative to provide Physics classes earlier in high school. This effort is supported by the same principles as the Physics First movement. We believe that Physics is necessary to provide a strong foundation for Chemistry and that Physics and Chemistry together provide the foundation for Biology. This philosophy is even more relevant today than it was at the inception of the Physics and Physiology program nearly 30 years ago, as recent advances in molecular science mean that high school biology classes are not like they were fifty or even fifteen years ago. These changes in biology have increasingly fostered the connections to and strengthened the need for grounding in chemistry and physics in biology students. They have also transformed biology a far more challenging subject with new vocabulary, and ideas, presented descriptively, with little indication to students of how the process of science really works. Physics, on the other hand, is largely concrete and practical, and can be taught in an exploratory fashion, using issues and examples from students’ daily lives. Using Physiology as a means to introduce and reinforce Physics concepts further provides relevance to students. This is supported in by student commentary in our course that they have realized that Physics really does apply to much of their daily lives.

Historically, the “problem” with Physics, and the reason that it has been taught last, is that it has been believed that students did not have the mathematical foundations necessary to handle a math-intensive course like traditional Physics earlier in high school. However, Physics can be taught earlier provided that students have had some basic algebra and certainly should be taught earlier to support algebra concepts as they are developing. Many attempts at teaching Physics first have been aimed at advanced placement classes, or have only succeeded with advanced placement students. Physics and Physiology is unique as far as we are aware, in its success with nearly all students in a heterogeneous classroom setting. Some of our students have commented that they have learned more math in science class than they have in math class.

The linkage of Physics and Physiology provides relevance to students and can be both an entry point and reinforcement to the Physics concepts. We find that our students are fascinated by topics that relate directly to themselves, which is the beauty of incorporating Physiology into the course. During a recent class when the skeletal system was introduced, the students asked questions about bone strength and flexibility for nearly the entire class period. Teaching physiology concepts provides information that students need to make healthy choices, and we hope promotes the making of such choices. And linking Physics and Physiology has an additional benefit: There is a national shortage of science teachers, but especially of Physics teachers. Many teachers of Physics have primarily had experience in life sciences. For these teachers who have backgrounds in the life sciences it can be less daunting to teach the a Physics course using Physiology as a natural complement to their existing knowledge.

Physics and Physiology is taught as an exploratory course. Students work in groups to ask questions, make predictions, and investigate problems. They use multiple representations to do this: they may write out a problem in words, draw a picture, and represent it mathematically or with a graph. Use of physiology concepts even allows us to employ some kinesthetic learning, and of course all of the laboratory activities are hands-on. In a heterogeneous classroom like that of P2, we find many learning styles and giving the students the option to think and to express themselves in these many different ways gives each student an opportunity to utilize their strengths while also challenging them to think in new ways. The technique of chart-boarding allows us to capture all of this on paper. Student groups use their own chart-paper to capture ideas and thoughts and they can refer back to them as they work through a problem or series of problems. The use of quadrilled chart-paper makes formulating tables and graphs much easier. Because students are often asked to verbally describe how they have solved a problem or designed an experiment, the large charts are also an ideal format for class presentation.

One result of our exploratory classroom structure is that students come out of the classroom with fewer facts than they might gain in a traditional Physics classroom. The emphasis is not on memorizing a series of equations and relationships, and problem solving is not presented using the “plug and chug” model to which generations of physics students have become accustomed. It is true that P2 students may not have memorized sets of equations and constants upon completion of the school year, but unlike in conventional classrooms, they emerge in possession of the tools they need to discover additional facts for themselves. One of the primary themes of the Physics and Physiology class is that the world has patterns, and not only can those patterns be expressed mathematically, but that any student can figure out what those patterns are for themselves. We feel that this end result is infinitely more valuable and empowering to the students than a head temporarily crammed full of facts and figures.

The pendulum lab is a good example of this pattern-discovering model. Most physics courses mention pendulum motion as a passing curiosity and throw the complicated formula T = 2π√L/g at students. Pendulums are more heavily emphasized in P2 because the phenomenon gives students an opportunity to observe, describe, and predict a natural phenomenon following a scientific process from beginning to end. Students begin by observing a pendulum, and then speculating about what may influence the period of its swing. They must then design a controlled experiment to test how things like mass, length of string, and angle of displacement might influence the period of a pendulum. These results are graphed and the students gather together at the “Association of Pendulum Scientists” conference to present their results. Having reached the conclusion that length of the string influences the period of the pendulum they may choose to share data with colleagues and then must determine the pattern of the relationship between length and period. When dividing length by time2, they discover a relationship: L =4T2 which corresponds very neatly to the more complex 2π√L/g, and makes more sense once they’ve discovered it for themselves.

The most exciting thing about this process is how empowering it is for the students. We follow up the simple pendulum lab with an examination of more complex pendulums, like swinging legs. When they employ their simple pendulum equation, they find it does not accurately define the length of their legs, but they know the reason is not that they have made errors in their mathematical calculations. As one student stated: “I know my leg is longer than this, but there must be some other reason this didn’t work, because I did the math right, and I can show you.” This statement from a student who at the beginning of the year, adamantly insisted, “I don’t know how” when asked to perform the simplest of mathematical operations to convert meters to kilometers. Students in P2 learn to do science. They learn to use the techniques and habits of mind used by scientists. They learn to think critically, to identify and control for sources of error, to solve problems, and evaluate and communicate their findings to other scientists.

Learning to do science does, of course, require a certain amount of laboratory equipment. Of concern to all teachers and school districts is expense of laboratory equipment. P2 emphasizes the use of cheap, easy to build equipment that can be constructed and maintained by teachers and students. Much of the equipment is also multi-functional, like the ramps used in the acceleration and projectile labs. Metersticks and paperclips—materials available in every classroom—are used to conduct balance and lever labs. Many of the physiology activities require only that the students use only their own bodies, moving their arms and legs for example, to examine first, second, and third class levers in the body.

Teamwork is an important aspect of the P2 class in development and in the classroom. Our development team includes experienced designers, content experts, teacher researchers, artists, and evaluators. In the classroom, students work as a team within their groups, and the entire classroom fills the role of a scientific community. Students are encouraged to work together to solve problems, and to share data and ideas with colleagues. Open communication between students and teachers is a necessity in this environment. Student feedback is the absolute best method by which the development team is able to determine how well an activity works. A statement as simple as “I’m confused” lets us know that an activity is in need of modification to be more conducive to student learning.

Assessment of student learning is accomplished by a variety of multidimensional techniques. Students are provided with homework exercises primarily as a means for them to practice new skills, and although they are given opportunities to discuss and review homework problems in class, they are checked for completion rather than content. Students keep lab notebooks and binders containing all their work, and these are collected on a regular basis as a way of assessing organizational skills. To assess content knowledge, traditional pencil and paper tests are used. Because we feel that understanding should be the primary goal, opportunities for retakes are provided. To encourage effort and study, however, half of the retake score is added onto the original score, meaning that poorly performing students have the opportunity to bring their scores up by the greatest margin. Students also keep a concept and skill inventory to keep track of their own progress of understanding. In this way they remain aware of which concepts they need additional assistance with. Teachers make themselves available during before school and lunch hours to provide that assistance with those concepts. Use of indicator questions on the exams also give us a clue as to how the class as a whole is performing. The manipulation of a simple three variable problem such as D=M/V that are prevalent in Physical science has been found to be a somewhat reliable indicator of the overall performance of the student. During the beginning pre-test given during the first week of school, only about 1/3 of the students could solve for M when provided the equation D = M/V. Over the course of the semester that percentage has steadily risen, with only about 15% of students still experiencing difficulty manipulating three variables at the close of the first semester.