Using a composite example of field trips from several years of traveling to Yellowstone with high school biology students, the author illustrates how to raise the cognitive level of science instruction and student learning through science field trips. The author examines what teachers can do to raise the level of both teaching and learning in all three phases of a field trip (pre, during, and post). It also illustrates the natural progression of learning through Bloom's taxonomic stages of cognition as the phases of the field trip progress. In other words, the highest levels of cognition (analysis, synthesis, and evaluation) occur after the field trip ends. The author describes her own experiences as an example of how to achieve this. This article also establishes the continuing need for field trips in spite of low budgets and the current drive for standardized and high stakes testing. (Contains 4 tables and 1 figure.)