Eleanor C. Sayre

What happens between pre- and post-tests: Multiple measurements of student understanding during an introductory physics course

To characterize the evolution of student understanding better than what is possible by pre-and post-testing, we posed simple conceptual questions several times per week to separate, randomly selected groups of introductory physics students. This design avoids issues of retesting and allows for tracking of student understanding of a given topic during the course with a resolution on the order of days. Based on the data from over 1600 students over five quarters, we found significant and interesting changes in performance on time scales of days and weeks. We found that the response curves of performance versus time can be divided into four categories: flat (no change), step-up, step-up and decay, and step-down. We examined changes on a 1 day time scale and found that changes in performance did not coincide with relevant traditional lectures or laboratories, but coincide with due dates of relevant on-line homework that provides immediate feedback. This method is well suited to measuring the effect of particu...

Resource Plasticity: Detailing a Common Chain of Reasoning with Damped Harmonic Motion

As part of ongoing research into cognitive processes and student thought, we have investigated the interplay between mathematics and physics resources in intermediate mechanics students. We present evidence from a reformed sophomore‐level mechanics class which contains both tutorial and lecture components. In the context of writing Newton’s Second Law for damped harmonic motion, students discuss the signs of the spring and damping forces. Using a grounded theory approach, we identify a common chain of reasoning in which a request for reasoning is followed by elaborative sense‐making and checks for consistency, finishing with an optional appeal for group consensus. Our analysis provides evidence for a description of student thinking in terms of Plasticity, an extension of Resource Theory.

Maximum Likelihood Estimation (MLE) of students’ understanding of vector subtraction

In this paper, we report on the impact that slight changes in question format have on student response to one‐dimensional vector subtraction tasks. We use Maximum Likelihood Estimation (MLE) analysis to analyze students’ responses on six very similar questions which vary in context (physics or mathematics), vector alignment (both pointing to the right or opposed), and operation (left‐right subtraction or right‐left subtraction). Responses on all questions are generally correct and do not vary by instructional week or even by course. Context and specific operation do not show significant differences. Vector alignment is significantly different, indicating that perception or heuristic thinking is a bigger cause of failure than conceptual deficit. The emphasis in this paper is an introduction to likelihood estimation.

Toward a comprehensive picture of student understanding of force, velocity, and acceleration

Students’ difficulties with conceptual questions about force, velocity, and acceleration have been well documented. However, there has been no single systematic study of student understanding of all paired relations among the concepts of force, velocity, and acceleration. For example, a student who believes an object with a net force on it must be moving might not believe an accelerating object must be moving. In this paper, we describe the development of a test to build a more comprehensive picture of student understanding. We describe modifications to increase the validity of the test by reducing false positives and unwanted inconsistencies. We also report preliminary data suggesting that there are definite patterns in student understanding of the various relations between force, velocity, and acceleration. For example, there are a higher number of students reporting that force and velocity are directionally related then that acceleration and velocity are directionally related.

Fluctuations in Student Understanding of Newton’s 3rd Law

We present data from a between‐student study on student response to questions on Newton’s Third Law given throughout the academic year. The study, conducted at Rochester Institute of Technology, involved students from the first and third of a three‐quarter sequence. Construction of a response curve reveals subtle dynamics in student learning not captured by simple pre/post testing. We find a a significant positive effect from direct instruction, peaking at the end of instruction on forces, that diminishes by the end of the quarter. Two quarters later, in physics III, a significant dip in correct response occurs when instruction changes from the vector quantities of electric forces and fields to the scalar quantity of electric potential. Student response rebounds to its initial values, however, once instruction returns to the vector‐based topics involving magnetic fields.

Students’ Responses To Different Representations Of A Vector Addition Question

We investigate if the visual representation of vectors can affect which methods students use to add them. We gave students one of four questions with different graphical representations, asking students to add the same two vectors. For students in an algebra-based class the arrangement of the vectors had a statistically significant effect on the vector addition method chosen while the addition or removal of a grid did not.

Evolution of Student Knowledge in a Traditional Introductory Classroom

In the physics education research community, a common format for evaluation is pre‐ and post‐tests. In this study, we collect student test data many times throughout a course, allowing for the measurement of the changes of student knowledge with a time resolution on the order of a few days. The data cover the first two quarters (mechanics, E&M) of a calculus‐based introductory sequence populated primarily by first‐ and second‐year engineering majors. To avoid the possibility of test‐retest effects, separate and quasi‐random subpopulations of students are evaluated every week of the quarter on a variety of tasks. Unsurprisingly for a traditional introductory course, there is little change on many conceptual questions. However, the data suggest that some student ideas peak and decay rapidly during a quarter, a pattern consistent with memory research yet unmeasurable by pre‐/post‐testing.

Using Social Network Analysis on classroom video data

We propose a novel application of Social Network Analysis (SNA) using classroom video data as a means of quantitatively and visually exploring the collaborations between students. The context for our study was a summer program that works with first generation students and deaf/hard-of-hearing students to engage in authentic science practice and develop a supportive community. We applied SNA to data from one activity during the two-week program to test our approach and as a means to begin to assess whether the goals of the program are being met. We used SNA to identify groups that were interacting in unexpected ways and then to highlight how individuals were contributing to the overall group behavior. We plan to expand our new use of SNA to video data on a larger scale.

Modeling students’ conceptual understanding of force, velocity, and acceleration

We have developed a multiple choice test designed to probe students’ conceptual understanding of the relationships among the directions of force, velocity, and acceleration. The test was administered to more than 800 students enrolled in standard or honors introductory physics courses or a second‐year physics majors course. The test was found to be reasonably statistically reliable, and correlations of test score with grade, course level, and the Force Concept Inventory were moderate to strong. Further analysis revealed that in addition to the common incorrect response that velocity must be in the direction of the acceleration or net force, up to 30% of students gave “partially correct” responses, for example that velocity can be either opposite to or in the direction of the acceleration or net force but not zero. The data also suggests that for some students their evolution of understanding may progress through this kind of partially incorrect understanding.