This activity discusses a two-day unit on ecology implemented during the summer of 2004 using the project-based science instructional (PBSI) approach. Through collaborative fieldwork, group discussions, presentations, and reflections, students planned, implemented, and reported their own scientific investigations on the environmental health of their local park in the borough of Queens, New York City. Students' questions included a wide range of topics that dealt with plants, animals, soil and water, and the interactions and relationships between these variables. Findings from students' reports and presentations indicated that the pH of the soil and pond water system at the park, as well as the characteristics of terrestrial and aquatic organisms, differ by location. In addition, results of the unit of instruction demonstrated that it is possible to teach students science content and process in a reasonably short period using the PBSI approach.