Effective investigations incorporate all four features of constructivist teaching. This high school or college-level field investigation guides teachers (and students) through the stages of inquiry. The focal concept is ecosystem function, specifically leaf decay rates in aquatic environments. Teachers elicit their students' prior knowledge and use it to generate discussion on variables that influence decay rates. Students engage in designing and conducting experiments. The learning cycle is continued when students apply their new knowledge and receive feedback, and completed when students return to their initial conceptions of leaf decay and reflect on the knowledge they gained through scientific experimentation.