Ironically, activating students' prior knowledge can be a mixed blessing if some of the prior knowledge is misleading or downright wrong. Misleading or erroneous knowledge is especially common among young students, but it can happen at any grade level. A kindergarten child may think that the sun literally “rises” in the morning, since she often hears adults use this expression, or that the earth is flat because it obviously looks flat. But a high school student may mistakenly believe that large objects (a boulder) fall faster than small ones (a pebble), or that a heavy object dropped (not thrown) from a moving car window will fall straight down instead of traveling laterally alongside the car while it falls.
Because misconceptions are quite common among students and even among adults, teachers are more effective if they can anticipate preconceptions of students wherever possible. The task is twofold. First the teacher must know or at least guess students' preconceptions as such as possible in advance, so that she can design learning activities to counteract and revise their thinking. Some preconceptions have been well documented by educational research and therefore can in principle be anticipated easily though they may still sometimes take a teacher by surprise during a busy activity or lesson (Tanner & Allen, 2005; Chiu & Lin, 2005). Exhibit 9.8 lists a few of these common preconceptions. Others may be unique to particular students, however, and a teacher may only by able to learn of them through experience by listening carefully to what students say and write and by watching what they do. A few preconceptions may be so ingrained or tied to other, more deeply held beliefs that students may resist giving them up, either consciously or unconsciously. It may be hard, for example, for some students to give up the idea that girls are less talented at math or science than are boys, even though research generally finds this is not the case (Hyde & Linn, 2006).
Misconception |
What to do |
Stars and constellations appear in the same place in the sky every night. |
Ask students to observe carefully the locations of a bright star once a week for several weeks. |
The world is flat, circular like a pancake. |
Use a globe or ball to find countries located over the horizon; use computer software (e.g. Global Earth) to illustrate how a round Earth can look flat up close. |
Dinosaurs disappeared at the same time that human beings appeared and because of human activity. |
Construct a timeline of major periods of Darwinian evolution. |
Rivers always flow from North to South. |
Identify rivers that flow South to North (e.g. the Red River in North Dakota and Canada); talk about how Southern locations are not necessarily “lower”. |
Force is needed not only to start an object moving, but to keep it moving. |
Explain the concept of inertia; demonstrate inertia using low-friction motion (e.g. with a hovercraft or dry-ice puck). |
Volume, weight, and size are identical concepts. |
Have students weigh objects of different sizes or volumes, and compare the results. |
Seasons happen because the Earth changes distance from the sun. |
Explain the tilt of Earth's axis using a globe and light as a model; demonstrate reduced heating of surfaces by placing similar surfaces outdoors at different angles to the sun's rays. |
Sources: Chi, 2005; D. Clark, 2006; Slotta & Chi, 2006; Owens, 2003.
The second task when anticipating preconceptions is to treat students' existing knowledge and beliefs with respect even when they do include misconceptions or errors. This may seem obvious in principle, but it needs remembering when students persist with misconceptions in spite of a teacher's efforts to teach alternative ideas or concepts. Most of us including most students have reasons for holding our beliefs, even when the beliefs do not agree with teachers, textbooks, or other authorities, and we appreciate having our beliefs treated with respect. Students are no different from other people in this regard. In a high school biology class, for example, some students may have personal reasons for not agreeing with the theory of evolution associated with Charles Darwin. For religious reasons they may support explanations of the origins of life that give a more active, interventionist role to God (Brum el, 2005). If their beliefs disagree with the teacher's or the textbook, then the disagreement needs to be acknowledged, but acknowledged respectfully. For some students (and perhaps some teachers), expressing fundamental disagreement respectfully may feel awkward, but it needs to be done nonetheless.
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