Fifteen Eighty Four

Students often come to school with not-quite-right or downright-wrong ideas about their physical and biological worlds. For example, some first graders might think of the Earth as being round in the same way that a pancake is round. And some older elementary school students might believe that our cave-dwelling predecessors lived at the same time that dinosaurs did.

Some misconceptions can persist well into the secondary and post-secondary years. For example, many high school and college students believe that (a) any moving object must have some sort of force acting on it, (b) human vision involves some sort of energy traveling from the eye to whatever is being looked at, and (c) it’s warmer in summer than in winter because the Earth is closer to the sun in summertime – a belief that obviously doesn’t take into account the fact that when the Northern Hemisphere is having summer, the Southern Hemisphere is having winter, and vice versa.

All three of these beliefs run counter to basic truths in physics, biology, and meteorology. After some sort of external force sets an object in motion, thanks to inertia – which is not a force, but rather a tendency for matter to keep its current state unless physically “persuaded” to do otherwise – the object continues to move at the same speed and in the same direction until some new external force (e.g., air resistance, gravity) acts on the object to change its speed and/or direction. Human vision is the result of light rays hitting and bouncing off of an object and then continuing on their merry way until they land on the retina of an eye; hence, energy goes to the eye rather than originating from the eye. And wherever we are on Earth, we have summer when the sun’s rays are hitting us more or less perpendicularly to the Earth’s surface; in contrast, they hit us at quite an angle in wintertime and thus they and the heat they give us are farther spread out.

Ideally, teachers need to help students revisit and revise their erroneous beliefs about the world in which they live. But in a previous blog post, I explained how we humans can sometimes be quite resistant to such conceptual change. One factor that impedes conceptual change in all of us is a general inclination toward confirmation bias: We tend to prefer and seek out information that confirms rather than contradicts what we currently believe. In addition, some of us have a strong need for closure: Those folks want quick and easy explanations for what might be fairly complex phenomena, and once they have those explanations, their minds are made up for the long run. Thus, they’ll stick stubbornly to the notion that “it’s warmest in summer because that’s when the Earth is closest to the sun” – never mind the fact that Antarctica has its coldest temperatures when it’s summer in the Northern Hemisphere.

It isn’t enough to simply give students correct explanations of why objects continue to move in space in the absence of an outside force, how vision actually works, or why it’s warmer in summer than in winter. Many students will simply memorize this information and store it in their long-term memories without mentally inspecting and revising their previous beliefs; thus, the misconceptions and the more scientifically valid explanations will both continue to exist in their long-term memories. And because the prior beliefs have been in long-term memory for a longer period of time, they tend to be more persistent than the correct explanations – they may often pop up and “override” the more scientifically accurate ones.

So, if you’re a teacher, what can you do to help students undergo conceptual change when warranted? Following are several strategies that researchers have found to be effective.

1. At the beginning of instruction, determine what students’ current beliefs about a phenomenon are. You can’t help students dismantle their erroneous beliefs unless both you and they are consciously aware of what those existing beliefs are. Asking questions in class is one possible approach. Another strategy – one that requires all students to think about the issue rather than remaining silent in a class Q-and-A session – is to administer a short, nongraded pretest that asks students to, say, write a short explanation about why it’s warmer in summer than in winter or to draw a diagram to illustrate the direction that energy travels when a person’s eyes sees\ an object.
2. Use physical models or verbal analogies to make abstract ideas more concrete and understandable for students. For example, use a small ball (the “Earth”), a much larger ball (the “Sun”), and several pieces of colored string to illustrate how the sun’s rays are farther apart when they hit a part of the Earth’s surface that is tilted away from the Sun. Or, in explaining how long human beings have populated the Earth, ask students to imagine the Earth’s history as a 24-hour day: People have lived on the Earth for only one minute of that day.
3. Bring both students’ prior conceptions and scientifically supported explanations into clear focus at the same time. Show students – perhaps with live demonstrations, physical models, or verbal analogies – how current scientific theories explain a phenomenon more effectively than students prior conceptions about the phenomenon do.
4. Ask students to apply the correct explanations to new situations. They might do this in laboratory activities, in computer-simulated “experiments,” in small cooperative-group activities, or on paper-pencil essay questions.
5. Remember that true, resilient conceptual change is apt to take time. Many students will have trouble letting go of some of their existing, self-constructed beliefs about scientific phenomena. Thus, you shouldn’t assume that a single, short lesson about a particular phenomenon will be enough. You’ll probably have to occasionally revisit it throughout the school year, and even in subsequent years if possible.

Find out more about ‘How We Think and Learn:Theoretical Perspectives and Practical Implications‘ By Jeanne Ellis Ormrod