One way for teachers to show a small specimen to an entire class is by placing the specimen in a small, transparent display case, such as a Petri dish. This allows students to closely observe the specimen and reduces the chance it might become damaged or destroyed. The Petri dish is also a good size to use with a magnifying lens or stereomicroscope. This article describes how to make a Petri dish display box for use in the science lab or the classroom.