A Matter of Misconceptions
by Anne Grall Reichel
As facilitators of learning we have the opportunity to orchestrate experiences that help children construct understanding. Often this requires the art of unraveling misconceptions associated with a given concept and building experiences that will provide evidence that can stand in contrast to the misconception. This is not a small charge, but it is certainly one worth pursuing.
The chapter entitled, "The Research Base," that sits quietly at the back of Benchmarks for Science Literacy (AAAS, 1993), can serve as a powerful tool for identifying common misconceptions that our students may hold. One of the misconceptions associated with matter provides us with the opportunity to explore phase change through the lens of a "system". "The Research Base" explains that children do not associate phase change as a system with energy gain and loss. Children may be aware of the fact that if a solid is changing to a liquid state that it requires the input of heat energy. What is less evident is the fact that the surrounding fluid is losing heat energy. But how do we facilitate the kind of experience that can help children build evidence that stands in contrast to this misconception?
Investigating ice, exploring systems
Starting with an ice cube in a glass of warm water have children observe the melting of the ice cube. Begin to ask questions associated with "systems" thinking. Is this a system? Why? Why not? Did anything in the system gain heat energy? Did anything in the system lose heat energy? How could we be certain? What instruments would you need to collect evidence? Most commonly students will be able to identify that the ice cube has gained heat energy because they can observe the ice cube becoming smaller and smaller. What will be less evident is the fact that the surrounding fluid has lost heat energy.
Ask students what they might do differently if they could repeat the investigation. Most likely they will suggest recording the temperature of the water before and after the melting of the ice cube. More dramatic results can be observed if dry ice is placed in colored water. As the dry ice sublimes*, a more observable temperature change occurs in the surrounding fluid and observable evidence of the fluids loss of heat is apparent because of formation of ice crystals at the top of the fluid.
According to the constructivist theory, in addition to the collection of evidence what becomes critical is an opportunity for students to verbalize, test, modify and perhaps even abandon pre-existing ideas. This can be accomplished by using what I like to call a KWLEQ. Primary teachers have had a great deal of experience with the KWL. (What I think I know, what I want to know, and what I learned.) Starting at this familiar place it is essential to bring out three additional thought processes through the following questions: What evidence do I have for what I know? (More simply stated for younger children "How did you know this?" or "What did you observe?") How is that different than what you initially thought? and What new questions do I have? (The "E" in the KWLEQ stands for "evidence", the "Q" for new "questions"). These three key questions ensure that students will address their initial ideas and begin to modify them in light of the new evidence.
The opportunity to ask new questions serves us well because learning can always be viewed as a beginning point rather than an end point. These questions provide a means for students to rewire their thinking through an active process of comparing data or evidence with their initial ideas. Initially they may not have realized that the surrounding fluid lost heat energy but by actively engaging in discussion of how the evidence supported the idea that the fluid lost energy they can begin to construct a new understanding of phase change from the perspective of a system
Another common misconception that can be addressed through the study of matter has to do with chemical change. Students often do not view a chemical change as an interaction. One of the most successful units I have used to discuss this interaction is the GEMS unit Chemical Reactions. In this constructivist unit students begin by observing a chemical reaction in a bag. They observe color change, production of gas and a change in temperature. Next they are challenged to use process of elimination to identify what reactants were responsible for the production of heat. As students work through the process they observe and feel that while one reactant released heat energy another gained heat energy. Because of the experiential nature of the activity, students gain an understanding of interaction and systems through their own invented process of elimination.
This unit is highly interactive because students do not follow a recipe but instead devise a methodology for determining what reactants generate heat. The strength of the Chemical Reactions unit lies in the fact that children get to do what scientists do. Instead of following an orchestrated "science recipe" they discover through a process of trial and error leading to elimination of variables.
The Research Base within "Benchmarks" holds great promise for planning interactive learning experiences for our students. Once we can begin planning with the misconceptions in mind we can work towards understanding in our classrooms.
*sublime: to pass directly from the solid to the vapor state.
Anne Grall Reichel
- Anne Grall Reichel is Science Literacy Coordinator for Lake County Educational Services, a division of the Regional Office of Education, Grayslake, Illinois. She is also facilitator of a Science Literacy Grant that focuses on design technology at Aurora Universiy.