Children often use ordinary objects to represent other objects—a block might become a phone, or a rock might become a cookie, during their play. This imaginative play means they understand that the “phone” and the “cookie” aren’t real but are chosen because they are very basic models of real objects, in that they have a certain shape and size that allows them to represent the real objects in play. The children are not trying to explain what a phone, or what a cookie is, but to use an object to represent another object as part of their play.
I’m wondering how accurate the models we adults use in teaching about a phenomenon have to be to avoid introducing or supporting misconceptions about that phenomenon. Is it important to accurately represent the body parts of a worm or is it okay to show them with eyes and smiling mouths? Is a blob of shaving cream floating on top of water a model that will help children understand the properties of a cloud of water vapor and how rain forms?
Conceptual models “allow scientists and engineers to better visualize and understand a phenomenon under investigation” (Framework page 56). How do you know if what you are presenting to children as an example, or conceptual model, of a natural phenomenon is scientifically accurate? And how do you know when a model has to be accurate to avoid introducing or supporting misconceptions about that phenomenon? In A Framework for K-12 Science Education: Practices, Crosscutting Concepts, and Core Ideas (National Research Council 2012) it is noted that, “Although they do not correspond exactly to the more complicated entity being modeled, they do bring certain features into focus while minimizing or obscuring others. Because all models contain approximations and assumptions that limit the range of validity of their application and the precision of their predictive power, it is important to recognize their limitations.”
The Important Book by Margaret Wise Brown is helpful at identifying what it is about an object that defines it (to the writer/speaker). Wise writes, “The important thing about snow is that it is white. It is cold, and light, it falls softly out of the sky, it is bright, and the shape of tiny stars, and crystals. It is always cold And it melts. But the important thing about snow is that it is white.”
We might use “instant snow” to represent actual snow, precipitation in the form of ice crystals, in play. If children have experienced snow they will be able to describe what is important about it and how the instant snow product resembles it, beyond both being white in color. To recognize the limitations of this model of snow I might say, “The important thing about instant snow is that it is white. It is cool, and light, it falls softly from my hand, it is bright, and the shape of tiny pieces. It does not melt. And it dries up. But the important thing about instant snow is that it is not real snow.”
The way we phrase our ideas can help children understand when a model more accurately represents a phenomenon or is a very simple “looks-like” model. We can say, “The shape of my cookie is like the Moon,” or, more accurately, “The shape of my cookie looks like how the Moon looks sometimes” (because the Moon is a three dimensional body in space, not a flat circle).
Read more about the use of models in A Framework for K-12 Science Education: Practices, Crosscutting Concepts, and Core Ideas (National Research Council 2012) pages 52-57.