The lesson plan outlines a 6th grade life science class where students will evaluate scientific investigations and theories that have changed over time by taking a gallery tour of famous scientists and their contributions. Key aspects of the plan include role playing a scientist's discovery, viewing a slideshow on scientists, doing a gallery walk to learn about 6 scientists, and reflecting on how the world may be different without one scientist's invention of the microscope. The goal is for students to understand that scientific knowledge is constantly evolving as new information is discovered.