# Math, Science, and Models: Fourth-Grade Students Express Erosion Understanding in an Interdisciplinary Way

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Young children are surrounded by models every day and accept them without much thought of how accurate or inaccurate they may be. They play with small objects--such as cars, people, animals, and airplanes--which represent larger objects, and with large objects--ants and spiders--that represent smaller objects. As they engage in play, they do not think about models as being an important part of science. They may not realize that scientists rely heavily on models to depict phenomena in the natural world, communicate ideas of what may be, and test ideas of what could be. Introducing children to the wonderful world of scientific models is rewarding for the student.

For the past five summers, we have taught summer school to recent immigrants and refugees. Our experiences with these fourth-grade English language learners (ELL) have taught us the value of using models to build scientific and mathematical concepts. In this article, we describe the use of different forms of 2- and 3-D models to show students how, when, and why scientists and mathematicians use models. In addition, we capitalize on how models can enhance the use of discipline-specific language. The language of science goes beyond natural language (oral and written). To make meaning in science, we also make use of "mathematical relationships, visual representations, and manual-technical operations" (Lemke 2004, p. 38). Although teachers may use models as tools for learning, they may not as often see their use as tools for expressing understanding. The use of models for expressing meaning is particularly helpful when working with ELL students.

Build on Prior Experience

To build on prior experiences with models, we began our unit on erosion by asking the students to talk about the models they encountered on a daily basis. Although the students had been in the United States for fewer than two years, they could easily draw from a variety of experiences with models. The students first associated the word model with fashion models. This discussion provided the opportunity to think about the differences in the everyday and academic meaning of the word model. We moved from its everyday understanding to its scientific meaning by taking advantage of the classroom environment and having students observe other types of models in the room (e.g., maps, globes, skeletons). Based on these initial observations, the student developed a working definition of a model as a representation of something real, similar to but not exactly like the actual thing (AAAS 2001).

Making Models

As we introduced the ELL students to the unit on erosion, we walked to sites on the school campus where evidence of erosion was obvious. Students saw the places where soil had washed away leaving cuts in the Earth and areas where sediment had deposited as piles of soil. Knowing we would be taking the children outside, we checked the area around the school yard for possible hazards and established that there were none.

After observing several sites, we asked students to select one and draw it in their journals as a 2-D representation (Figure 1). Knowing that we would use these drawings later to make a connection to other types of models, we highlighted the importance of journals as a place to capture data that could be used at a later time.

Working in small groups, the students revisited their journals and discussed the various erosion sites they had observed on the school walk. Within these groups, the students selected a site they wished to represent, and used their 2-D drawing to construct a 3-D model using Crayola Air-Dry Clay (a substance which hardens after a few hours). We selected clay but any material may be used--for example, paper-mache or Lego bricks. Some children may be allergic to modeling clay. Be sure to have gloves for students needing them. As the models hardened and became fixed, the students were asked to look at another group's model and determine which site the model represented. …