N. Sanjay Rebello

Quantum mechanics for everyone: Hands-on activities integrated with technology

Quantum mechanics is frequently taught toward the end of the first year of physics if it is taught at all. Many physics instructors believe that quantum mechanics is a very abstract subject that cannot be understood until students have learned much of classical physics. We are challenging this belief by creating instructional materials for quantum mechanics that can be integrated throughout the first physics course. In addition, we have transferred some of the materials and the basic approach to higher-level courses. The result is a hands-on approach to learning and teaching quantum mechanics for a broad spectrum of students. We describe some of our materials and the results of using these materials with students.

The effect of distracters on student performance on the force concept inventory

We have compared students’ responses on four multiple-choice force concept inventory (FCI) questions with similar responses to equivalent open-ended questions. Our results indicate a good agreement between the percentages of correct responses in each of the two formats, indicating that distracters on the FCI do not adversely affect performance as measured by the number of correct answers. However, a significant percentage of the open-ended responses fall into categories that are not included in the FCI multiple choices. When these alternative categories were presented to the students as distracters in a revised multiple-choice format, a significant percentage of the students chose these alternative responses.

The Teaching Experiment — What it is and what it isn’t

Much of the research investigating how a student reasons or what knowledge structures they possess and utilize has typically been done using clinical interviews. Clinical interviews are often semi‐structured and may or may not involve demonstration equipment. In the early 1980’s, mathematics researchers began using a new style of interviewing which they termed the “teaching experiment.” These two methods will be compared and contrasted within the context of sound. Two groups of students from a conceptually‐based introductory physics course were interviewed in an effort to understand how they view the production of sound in musical instruments; one group was interviewed using clinical interviews while the second group was interviewed using the teaching experiment.

The Vocabulary of Introductory Physics and Its Implications for Learning Physics

In science new words might be “invented” to name or describe new processes, discoveries, or inventions. However, for the most part, the scientific vocabulary is formed from words we use throughout our lives in everyday language. When we begin studying science we learn new meanings of words we had previously used. Sometimes these new meanings may contradict everyday meanings or seem counterintuitive. We often learn words in association with objects and situations.1 Due to these associations that students bring to class, they may not interpret the physics meaning correctly. This misinterpretation of language leads students to confusion that is sometimes classified as a misconception.2–6 Research about the semantics used in physics textbooks7–9 and the meaning of words has been done,10–12 but the problem seems to go beyond semantics.8 The linguistic relativity hypothesis, sometimes referred to as the Sapir-Whorf hypothesis,1 says that “we see and hear and otherwise experience very largely as we do because th...

Impact of a Classroom Interaction System on Student Learning

We have developed and implemented a Web‐based wireless classroom interaction system in a large‐enrollment introductory physics lecture class that uses HP handheld computers (PDAs) to facilitate real‐time two‐way student interaction with the instructor. Our system is ahead of other “clicker” based PRS (Personal Response System) that is limited to multiple‐choice questions. Our system allows for a variety of questions. It also allows for adaptive questioning and two‐way communication that provides real‐time feedback to the instructor. We have seen improved performance on course assessments through use of PDAs compared to PRS in the same class. We have also shown that students who use PDAs more often in class are more likely to perform better in the course.

Visualizing motion in potential wells

The concept of potential-energy diagrams is of fundamental importance in the study of quantum physics. Yet, students are rarely exposed to this powerful alternative description in introductory classes and thus have difficulty comprehending its significance when they encounter it in beginning-level quantum courses. We describe a learning unit that incorporates a sequence of computer-interfaced experiments using dynamics or air-track systems. This unit is designed to make the learning of potential-energy diagrams less abstract. Students begin by constructing the harmonic or square-well potential diagrams using either the velocity data and assuming conservation of energy or the force-displacement graph for the elastic interaction of an object constrained by springs or bouncing off springy blocks. Then, they investigate the motion of a rider magnet interacting with a configuration of field magnets and plot directly the potential-energy diagrams using a magnetic field sensor. The ease of measurement allows exp...

How Many Students Does It Take Before We See the Light

Prior research suggests that students who cannot light a bulb given a single wire, a bulb, and a battery are not able to reason correctly regarding complete circuits. Our research shows that students believe that the wires from the filament are connected to the base of the bulb at the bottom. The percentage of students with this belief seems to be dependent on the level of the introductory physics course taken (conceptual, algebra, calculus). We have proposed three activities that appear to aid students in developing the correct model of how a light bulb is wired and a definition of complete circuit that classifies a short circuit as a complete circuit but one that is not advantageous.

Using ScanMatch scores to understand differences in eye movements between correct and incorrect solvers on physics problems

Using a ScanMatch algorithm we investigate scan path differences between subjects who answer physics problems correctly and incorrectly. This algorithm bins a saccade sequence spatially and temporally, recodes this information to create a sequence of letters representing fixation location, duration and order, and compares two sequences to generate a similarity score. We recorded eye movements of 24 individuals on six physics problems containing diagrams with areas consistent with a novice-like response and areas of high perceptual salience. We calculated average ScanMatch similarity scores comparing correct solvers to one another (C-C), incorrect solvers to one another (I-I), and correct solvers to incorrect solvers (C-I). We found statistically significant differences between the C-C and I-I comparisons on only one of the problems. This seems to imply that top down processes relying on incorrect domain knowledge, rather than bottom up processes driven by perceptual salience, determine the eye movements of incorrect solvers.

How does visual attention differ between experts and novices on physics problems

Research in many disciplines has used eye‐tracking technology to investigate the differences in the visual attention of experts and novices. For example, it has been shown that experts in art and chess spend more time than novices looking at relevant information. Thus, it may be helpful to give novices more direct insight into the way experts allocate their visual attention, for example using attentional cueing techniques. However, not much is known about how experts allocate their attention on physics problems. More specifically, we look at physics problems where the critical information needed to answer the problem is contained in a diagram. This study uses eye movements to investigate how the allocation of visual attention differs between experts and novices on these types of physics problems. We find that in several problems tested, those who answered a question correctly spend more time looking at thematically relevant areas while those who answer incorrectly spend more time looking at perceptually s...

Retention and Transfer from Trigonometry to Physics

We examined the extent to which students retained and transferred various concepts from trigonometry to physics at the introductory college level. Online trigonometry homework assignments and pre‐ and post‐instruction surveys in physics were our sources of data. Transfer was measured from a traditional as well as two contemporary perspectives. Students seemed to have more difficulty retaining and transferring the unit circle concept compared to others. Transfer was more evident when measured from some contemporary perspectives rather than a traditional perspective.