Preschoolers receive inadequate science instruction despite preschool science benefits and adopting early learning science standards in New Jersey. This qualitative exploratory case study explored 17 preschool teachers of 4-year-old students' perceptions of using the New Jersey Preschool Teaching and Learning Standards for science and how they integrated science concepts and instructional practices into the preschool curriculum in a Northern New Jersey public school district. Preschool teachers were recruited using purposive sampling. Semi-structured interview transcripts, qualitative questionnaire responses, field notes, and archival documents were analyzed and triangulated to the study's findings and two research questions. The first research question explored preschool teachers' perceptions of applying the New Jersey Preschool Teaching and Learning Standards for Science to develop instructional practices in the classroom curriculum. The second research question explored how preschool teachers perceived their role in teaching science concepts. Open coding, thematic analysis, and NVivo12 coding software revealed three themes: (1) Preschool teachers engage in bounded decision-making, (2) Beliefs in teaching preschool science for later academic and career success, and (3) Preschool teachers' perceptions of their preparedness in teaching science concepts. The results had implications for early childhood settings, including (1) Preschool teachers required more funding, resources, and support to implement science concepts from administrators, (2) Teacher preparation programs offer more science courses to assist teachers in learning science concepts and standards, and (3) Preschool teachers participate in professional learning communities to build capacity for science. [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.]