This qualitative exploratory study investigated practicing and pre-service elementary teachers' representations of the nature of matter and the ways in which those representations were transformed into teaching representations. Seven practicing elementary teachers from a rural elementary school and five pre-service elementary teachers were asked to draw their personal external representations of a sugar cube, wooden toothpick, liquid water, copper wire and a helium balloon. Next, they were asked to draw their personal external representations of properties of the objects and physical processes they can undergo. Then they were asked to draw their personal external teaching representations or describe other methods they would use to teach elementary students about the nature of matter. Each participant was concurrently interviewed about their representations. Analysis of the data was used to build profiles of each participant. In general, results of this study indicated that practicing elementary teachers tended to draw and explain the nature of matter at the macroscopic level both for themselves and for their students. They also tended to focus on how an object was manufactured or human uses of the object rather than providing explanations that described or explained the composition of each object or properties and processes each object could undergo. The pre-service elementary teachers tended to draw molecular representations that described and explained both composition of the objects and their properties and processes. Pre-service elementary teachers also tended to express opinions that elementary students could learn about atoms and molecules whereas practicing elementary teachers tended to view elementary students as concrete learners. Implications for research and teaching will be discussed in Chapter 5 of this dissertation. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]