Shimizu (2003) has pointed out that when a child studies leaf arrangement, study through model-making reveals more rules to the child than study through sketching. This research looks at why this is so. The research focuses on differences in understanding of the outside world from different view points (model-making vs. sketching), in particular on the effect to interaction between individuals studying in small groups, how natural discussion arises between the children studying and the effects of the discussion. Analysis of the children's conversation showed that children in the model-making group talked more often and at greater length than those in the sketching group, and that their conversation more often concerned the rules of leaf arrangement. These results suggest that an environment where students can see each others models promotes learning, and is effective for assisting the discovery of scientific concepts. Sketching is often used to encourage close observation at elementary and junior high school level. However, as it is difficult to sketch accurately, and sketches are often lacking in detail information, it may be necessary to reexamine the guidance given on use of sketching in schools.