Ten results of physics education research that every physics instructor should know
This is a draft outline for an article describing the results of physics education research that are most important for practicing physics instructors to know and apply in their classrooms. We will be publishing the results in installments on PhysPort. The goals of this article are to explain the research behind each result in enough detail that readers can easily understand why we believe each result to be true, and to offer suggestions for how to incorporate each result into their teaching.
- PER-based teaching methods improve student learning of physics. Implication: Use PER-based teaching methods.
- PER-based methods are effective for students at all levels of ability. Implication: These methods will help even your best students.
- Learning from PER-based methods lasts for multiple years. Implication: These methods will provide more than a quick fix.
- Students' everyday ideas about the world affect their learning of physics. Implication: Seeing the world from your students' perspective will make you a more effective teacher.
- The way students structure their knowledge affects their learning of physics. Implication: Give your students opportunities to practice organizing their knowledge.
- Traditional lectures don't change students' everyday ideas or knowledge structure. Implication: Intersperse lectures with activities that engage students and get them asking questions that the lectures will answer.
- Traditional demonstrations don't change students' everyday ideas or knowledge structure. Implication: Before a demonstration, ask students to predict the results of an experiment or to design an experiment.
- Successfully solving problems does not necessarily lead to conceptual understanding. Implication: Traditional exams are insufficient for assessing student understanding.
- However, conceptual understanding can improve the ability to solve problems. Implication: Devote more time to helping students develop conceptual understanding, even at the expense of spending time on problem solving.
- Most physics classes harm students' beliefs about physics. However, there are ways to do better. Implication: Use teaching methods that reward reasoning, questioning, sense-making, and connecting physics to the real world.
- Students' beliefs about learning physics affect their learning of physics. Implication: To improve your students' learning physics, teach them how to learn physics.
- Effective implementation and adaptation requires understanding how these methods work. Implication: Learn the rationale behind the teaching method you are using before you adapt it to fit your environment and goals.
1. PER-based teaching methods improve student learning of physics.
Implication: Use PER-based teaching methods.
PER-based teaching methods, also known as "interactive engagement" or "active learning" methods, are defined by Meltzer and Thornton as sharing the following three features: "(1) they are explicitly based on research in the learning and teaching of physics; (2) they incorporate classroom and/or laboratory activities that require all students to express their thinking through speaking, writing, or other actions that go beyond listening and the copying of notes; (3) they have been tested repeatedly in actual classroom settings and have yielded objective evidence of improved student learning." Teaching methods that include these features have been repeatedly demonstrated dramatically improve student learning over traditional lecture methods.
The difference in student learning between traditional methods and PER-based methods has been demonstrated over a wide range of students, classes, and institutions using a test called the Force Concept Inventory (FCI)(Hestenes, Wells, & Swackhamer, 1992). The FCI is a multiple-choice test with conceptual questions based on research into student thinking about physics. These questions ask about students' basic model of the world and require minimal calculations. Many physics instructors are reluctant to give their students this test because the questions appear "too easy." Most physics instructors imagine that their students should be able to answer these questions easily and fear that students will be insulted by the simplicity of them.
In a 1998 study (Hake), Hake collected FCI results from 6000 students in introductory physics classes at many institutions and using many kinds of instruction, and found that across the board, students learned very little about the basic concepts of force and acceleration in courses taught with traditional lecture methods. In each class, students were given the FCI at the beginning and at the end of instruction, and the improvement was calculated using the normalized gain, a measure of how much the students learned as a percentage of how much they could have learned:
Normalized gain = <g> = (%post-%pre)/(100%-%pre)
His results are shown in the figure at right. Hake found that the average normalized gain for classes taught with traditional lecture instruction was 23%, with a range from 13% to 29%. There were no classes taught with this method in which students improved more than 30% between the beginning and the end of the course. For courses taught with interactive engagement methods, the average normalized gain was 48%, with a range from 21% to 69%.
Since 1998, many instructors have been inspired by the Hake study to try giving the FCI in their courses, including popular award-winning lecturers, and no one has ever reported a gain higher than 30% for a course using traditional lecture instruction. Many studies since 1998 have reported gains similar to or higher than those reported by Hake in courses using interactive engagement methods. For an overview of more recent studies, see Meltzer and Thornton (2012) .
1a. PER-based methods are effective for students at all levels of ability.
Implication: These methods will help even your best students.
Physics instructors often think that interactive engagement methods are somehow "remedial" or only appropriate for weaker students. After all, most successful physicists learned from traditional lecture instruction, and we’ve been doing it for generations, so it must be the best way. However, there are several research studies showing that interactive engagement methods help students at all levels of ability, including the strongest students. These results suggest that perhaps successful physicists learned physics in spite of, rather than because of, the traditional lecture instruction they received in school.
At the University of Minnesota, Heller, Keith, and Anderson showed that when students used Cooperative Group Problem Solving, the solutions of students working in groups were significantly better than the solutions of the best individual student in the group working alone. Further, the problem-solving scores of the weak, medium, and strong students all improved over time. These results demonstrate that even the strongest students benefit from group work.
At Harvard, Crouch and Mazur found that in a class using Peer Instruction, no student initially gave the correct answer to a concepTest more than 80% of the time. Even at Harvard, there are no students who always know the answer to these conceptual questions. This suggests that such questions are valuable even for the strongest students.
In a longitudinal study of physics majors at the University of Colorado, Pollock found that students who had taken introductory electromagnetism courses using Tutorials in Introductory Physics with learning assistants received slightly better course grades in a traditionally taught junior-level electromagnetism course, suggesting that the tutorials did not hurt and may have helped these students' performance in the one of the core physics courses most valued by physics faculty.
1b. Learning from PER-based methods lasts for multiple years.
Implication: These methods will provide more than a quick fix.
There is substantial evidence that interactive engagement methods can lead to significant gains in student learning in the short term. But do these gains last over time? In contrast to results in other fields that learning, especially rote learning, is often short-lived, several studies in PER have shown that learning gains from research-based interactive engagement methods persist years after instruction.
In the most well-known and clear-cut of these studies, Francis, Adams, and Noonan tracked down students 1-3 years after they completed algebra-based introductory physics courses that used Tutorials in Introductory Physics, and asked them to take the FCI again. These students had taken the FCI at the beginning and end of the course, so the authors of the study were able to compare the scores for the same group of students using matched data. When these students took the FCI 1, 2 or even 3 years later, their scores were nearly as high as they had been at the end of the course.
Bernhard published a study in 2001 looking at pre-service teachers in an introductory mechanics course in Sweden using an adaptation of RealTime Physics. The pre-service took the FCI 2.5 years after the completion of the course, and scored almost as high as a group of civil engineering students who had just completed a more refined version of the same course.
In 2009, Pollock published a similar study at the University of Colorado physics majors after completed introductory electromagnetism courses that included Tutorials in Introductory Physics and Peer Instruction. These students were given the BEMA, a survey of conceptual understanding of electromagnetism which is similar to the FCI but more difficult, at the beginning and end of their introductory electromagnetism course, and then again at the end of either their first or second semester of junior level electromagnetism. The BEMA scores increased significantly between the beginning and end of the introductory E&M courses, but dropped only slightly between the end of the introductory courses and the end of the junior-level courses. A smaller group of students took the BEMA at the beginning of the junior-level course, and did not have significantly different scores from those who took it at the end of the course.
2. Students' everyday ideas about the world affect their learning of physics.
3. The way students structure their knowledge affects their learning of physics.
4. Traditional lectures don't change students' everyday ideas or knowledge structure.
5. Traditional demonstrations don't change students' everyday ideas or knowledge structure.
6. Successfully solving problems does not necessarily lead to conceptual understanding.
7. However, conceptual understanding can improve the ability to solve problems.
8. Most physics classes harm students' beliefs about physics. However, there are ways to do better.
9. Students' beliefs about learning physics affect their learning of physics.
10. Effective implementation and adaptation requires understanding how these methods work.