Live organisms versus digital video of the organisms were used to challenge students' naive ideas and misconceptions about blood, the heart, and circulatory patterns. Three faculty members taught 259 grade 10 biology students in a California high school with students from diverse ethnolinguistic groups who were divided into 5 classes using microscopes (128 students) and 5 classes using digital video (131 students) to compare blood transport among invertebrates, fish, and humans. The “What Is Happening in this Class?” (WIHIC) questionnaire was used for assessment of microscope and video groups to detect students' perception of their learning environment following these teaching interventions. The use of microscopes had a clear effect on the perception of the investigative aspects of the learning environment that was not detected with the video treatment. Findings suggest that video should not replace investigations with live organisms.