What is the typical shape of a Petri dish?

The typical shape of a Petri dish is circular. This design is practical for a number of reasons. The circular shape allows for even distribution of agar or culture media, which promotes uniform growth of microorganisms across the surface. It also facilitates 360-degree access for sampling or observation and minimizes edge effects by keeping the growth environment consistent throughout the dish.

In laboratory settings, the circular design of Petri dishes fits well within incubators and sterile environments, allowing efficient use of space. While other shapes like square or rectangular dishes exist for specific applications, the circular Petri dish is most commonly used in microbiology and cell culture, making it the standard shape.