What We Know

Physical sciences, generally defined as chemistry and physics, are important areas of science education. Ohio’s students should have opportunities to learn about chemical and physical principles, the nature of matter, forces, motion and energy in order to construct personal frameworks of knowledge about the physical world. As young people learn basic principles that describe the world around them and predict possibilities, they also learn about the limitations of human understanding and the nature of the scientific endeavor to expand human understanding of some complex physical systems. 

When students learn physical sciences through investigation and discovery, they build on what they have learned through observation, invention and play.  Application of technical terminology and mathematical descriptions come after investigations and discussions of relevant concepts and clarification of misconceptions, as teachers assist students in building conceptual models and solving scientific and technological problems.

What are some common misconceptions in physical sciences and how can they be addressed through teaching?

Arnold B. Arons (1990) and others have found that students often hold similar misconceptions. Teachers should be aware of student misconceptions before beginning instruction and understand why these misconceptions exist. Keith Taber (2003) asserts that not only should teachers address misconceptions that are present, they should be particularly careful not to create misconceptions through instruction. The next several paragraphs present many commonly held misconceptions in the physical sciences.

James H. Wandersee, Joel J. Mintzes and Joseph D. Novak (1994) synthesized several research sources and found that many students believe that motion indicates force, and that students demonstrate an inability to predict the course of a moving object using Newton’s Laws. They also found that students are confused by the relationship between weight and gravity, by velocity and its causes, and by the concept of energy. Misconceptions also exist related to light, reflection, refraction and absorption. Antti Savinainen and Philip Scott (2002) concur that Newton’s Laws of Motion and the relationship between force, mass and velocity are common misconceptions. Moreover, Savinainen and Scott found that some students’ misconceptions are often perpetuated and reinforced by instruction including the misconcept that “velocity is proportional to force.”

Ngoc-Loan Nguyen and David E. Meltzer (2003) point out that to be successful in introductory physics, students need to have an understanding of basic vector concepts. Common student misconceptions in applying vector concepts include the assumption that vectors can have equal magnitudes only when they are parallel or perpendicular to each other. Nguyen and Meltzer noted that students arrive in college physics classrooms with these misconceptions.  College instructors often are not aware of this and spend very little time on review, allowing these misconceptions to remain.

In their synthesis of research, Wandersee, Mintzes and Novak express that common chemistry misconceptions include confusion about relative electronegativity of atoms and polarity of molecules. They also note that students tend to transfer macroproperties of elements to the micro world.  Misconceptions also abound regarding       the concept of equilibrium and subatomic structure. Vanessa Barker (2000) lists further misconceptions commonly held by chemistry students including that non-rigid solids are classified differently than rigid ones, and that substances that are not like water are not liquids, even though they may be actually classified as such.  Barker identified that students also lack an understanding of the strengths and locations of inter- and intra-molecular bonds. Barker expresses concern that misconceptions derived from early learning experiences are very difficult for students to overcome, even when provided with accurate, technical information. Introducing technical terminology before students develop rudimentary understandings of concepts may result in misconceptions, as the scientific terms often have quite different meanings in chemistry than those used in everyday life. Taber concurs that definitions should be reserved until the concept is understood by students.

George Papageorgiou (2002) reports that seventh-grade and eighth-grade students have difficulty differentiating between a chemical compound and a mixture, although this is one of the most basic concepts in chemistry.  Richard K. Coll and David F. Treagust (2003) note that ion size and shape also cause confusion among students at this level, possibly due to the limitations of model representations. Helmut Fischler and Michael Lichtfeldt (1992) report that frequently occurring misconceptions include the existence of electrons in fixed orbits around the nucleus and rigid application of the octet rule, and repulsion between charges. Other common misconceptions relate to volume displacement; boiling, condensation and evaporation of water; the correlation between amount and reacting mass; the relationship between mass, volume and moles; the conservation of volume; the particulate nature of matter; the meaning of the word neutral; and the difference between heat and temperature. Dorothy Gabel and Diane Bunce (1994) found in many cases, elementary school teachers hold the same misconceptions exhibited by adolescent students. 

Coll and Treagust relate that models are essential in chemistry education and can be useful to dispel student misconceptions. Unfortunately, some inaccurate models exist in textbooks and correct models used by scientists and teachers can be misinterpreted by students. Taber suggests that teachers use analogies and metaphors to connect new information to a student’s existing knowledge base. He cautions, however, that students often take such teaching aids literally. Coll and Treagust recommend that chemistry teachers help students make connections between large scale models and microscopic properties of materials, help students see the limitations of the simple models and remind students that models are not actual depictions of reality but just representations. Kalkanis, Hadzidaki and Stavrou (2003) stress that the use of models to depict phenomena relevant to quantum mechanics may lead students to believe that the models are more than representations. For example, many students hold fast to Bohr’s model of the atom presented in early chemistry classes. 

Teachers can use a variety of strategies to discover and address students’ misconceptions. Savinainen and Scott, along with Taber, recommend that students use concept maps to organize thoughts and make connections between ideas, and that students summarize their work in writing. (For more information on concept mapping and journaling, see Classroom Assessment in Science Education.)

Manivannan and Meltzer (2001) advocate the use of formative assessment through flash card responses to multiple-choice questions during demonstrations or class discussions. The teacher is able to observe the frequency and extent of student misconceptions. Teachers should be certain that even minor concepts are fully understood by students in order to promote student success with increasingly complex problems.

Carlos Eduard Laburu and Mansoor Niaz (2002) suggest that teachers address student misconceptions by encouraging discussion and reflection, and using conflicting situations to bring about conceptual change. Kalkanis et al. advocate teaching science based on a learning process that includes an effort by learners to explain their world. Teachers should begin instruction with knowledge of students’ current understandings, even if they hold inaccurate ideas. The authors also advocate creating a cognitive conflict that causes learners to question what they believe to be true. This questioning leads to a restructuring of knowledge. Kalkanis et al. found that a scientific inquiry approach drawing upon students’ understandings and experiences is beneficial in developing cognitive change in students. (For more information on teaching and learning science through inquiry, see Scientific Inquiry.)

Several researchers advocate peer instruction as a strategy to expose and confront misconceptions. Patricia Basili and Julie Sanford (1991) followed a group of community college students and found that having the opportunity to discuss science concepts freely among peers without the overt influence of an authority figure provided students the chance to correct the misunderstandings of others and reach a conclusion reflecting the correct concept. They recommend that the teacher provide direct instruction in the initial stages of learning, but also that good leadership behaviors should be taught to students and reinforced by being made a formal part of the group grading procedure to promote effective discussion. Basili and Sanford suggest that teachers provide questions for group discussion that link science concepts with observable events that occur in students’ lives. Craig Bowen and Amy Phelps (1997) also advocate the use of cooperative learning groups to further enhance learning and the development of a more positive attitude toward chemistry.  They indicate that students participating in cooperative groups and utilizing peer feedback and assistance exhibited fewer misconceptions and better conceptual understanding than students who did not. 

What are the roles of demonstrations, investigations and laboratory experiences in teaching and learning physical sciences?

According to David E. Meltzer and Amy Woodland Espinoza (1997), guided scientific inquiry is increasingly emphasized in the middle school physics curriculum. Students are encouraged to discover physical principles before the teacher describes them. Teachers introduce a topic in an interesting way and then promote class discussion including predictions relating to the topic. Teachers then present basic terminology relevant to the topic, allowing students to discover the law through independent or small group investigation followed by another class discussion. The authors suggest that teachers move about the classroom offering assistance and questioning students during investigations. Class discussion will likely reveal minor variations in findings, thus illustrating the concept of experimental variance. Once the class reaches a consensus, the teacher can confirm the law studied.  Similarly, Douglas Arion, Kevin Crosby and E. Murphy (2000) advocate the use of scientific inquiry-based activities, indicating that doing so improves students’ attitudes toward and understanding of physics. Scientific inquiry-based lessons create opportunities for students to confront and revise their understandings and misconceptions, as well as to experience scientific processes as a scientist does. Students may develop a positive attitude towards physics that often leads to better retention of knowledge and understanding that improves performance on assessments. (For more information on teaching science through inquiry, see Scientific Inquiry.)

Antti Savinainen and Philip Scott, as well as Jeff Cohen et al. (2000), advocate the presentation of concepts with little mathematical connection through demonstration followed by discussion. Only after students indicate a clear understanding of the concept should mathematical problem-solving be presented. 

According to Bowen and Phelps, demonstrations are essential to chemistry education, yet to be useful in instruction and assessment, they must be conducted properly. Manivannan and Meltzer relate that these demonstrations must be structured to include tasks that keep students actively observing and processing information related to their observations. Questions given to students should extend students’ thinking about the concepts presented in the demonstration. During demonstrations, students should be asked to record observations (e.g., identification of products, descriptions of events), rather than to simply predict what they expect to happen. Bowen and Phelps report that demonstration-based assessments enhanced performance on more traditional tests that focused on understanding of concepts. 

Manivannan and Meltzer describe the effectiveness of a problem-solving approach that involves the division of a physics demonstration into several conceptually linked smaller demonstrations. This approach allows both students and the teacher the opportunity to recognize and address misconceptions as the demonstration progresses. In this technique, students are encouraged to discuss initial predictions with other students, first in a small group, then as a whole class. The authors report that this technique successfully promotes active learning.

Joseph Snir and Carol Smith (1995) recommend using laboratory experiences to engage students in physical concepts, then having students draw models or graphic representations of their understandings of the experience. Peer review and discussion follows the presentation of the models, helping students evaluate the effectiveness of models and forcing them to confront their misunderstandings of concepts and of the models themselves.

What is the role of problem-solving in physical sciences education?

Gabel and Bunce note that when students simply attempt to put numbers into formulas in order to problem-solve, they demonstrate no real understanding of concepts and are not truly learning. Algorithmic problem-solvers typically do not know what to do when faced with a new problem. True problem-solving includes conceptual knowledge as well as an ability to approach a problem strategically and systematically. Concept knowledge must be developed for students to be successful problem-solvers.

David Maloney (1994) stresses that problem-solving is a crucial component of physical sciences education at all grade levels. The ability to solve physics problems requires conceptual understanding and the ability to approach the problem in an effective way. Students need to understand the problem, devise and implement a plan for solving the problem and be able to evaluate the solution for correctness. Efficient problem-solvers approach a problem with an effective plan and with a hierarchical organization of knowledge.  Working cooperatively with peers may enhance a student’s problem-solving ability. Maloney suggests that the use of complex problems with multiple possible solutions in science lessons is representative of real-world situations because scientists typically work with such problems. 

Bowen and Phelps explain that chemistry problems may be expressed in different ways - symbolically through equations, at the particulate level through diagrams or at the macroscopic level through laboratories and demonstrations.  Successful problem-solvers can easily move between different representations. Thus it is important for teachers to instruct using each of these methods so students are able to connect all representations.

To become successful at problem-solving related to proportions, students must be able to express their understanding in narrative form, rather than to simply memorize formulas or steps to solving equations. It is equally important for students to express the thought processes that lead to a solution as it is to compute correctly. Cohen and his colleagues found that when students have difficulty with equations, it is because they have difficulty expressing their thought processes relating to the equation, not because they have difficulty with computation. 

Gabel and Bunce found that students may become confused by technical terminology or too many unknown variables. This could prevent them from approaching a problem confidently. When a problem involves multiple steps, the student may be unable to solve the problem. To increase student success, teachers should instruct students in the skill of breaking down complicated problems into smaller parts that can be solved in sequence.  Jeff Cohen suggests that as students discuss the problem in groups, the teacher circulate among the students, asking questions to develop their thinking about the problem. After a short period of conversation and reflection, the entire class discusses the problem and reaches consensus on the answer. This communication among students also makes misconceptions more apparent to the teacher. Patricia Heller and Kenneth Heller (1999) also advocate teaching physics students a systematic problem-solving strategy and having students solve problems in cooperative groups. They endorse giving students context-rich problems, which contain extraneous information. Having students choose which pieces of information are necessary to solve the problem mirrors real-world problem-solving situations while challenging students to remember the concepts necessary to solve the problem.