Petri Dishes

Petri dishes are essential laboratory tools used primarily in microbiology, cell culture, and chemical analysis to cultivate and observe the growth of microorganisms, cells, and small plants under controlled conditions. These shallow, cylindrical, lidded dishes are usually made from glass or plastic, with plastic varieties often being disposable to maintain sterility and ease of use.

Key quantifiable features of Petri dishes include their standard sizes, typically ranging in diameter from 35 mm to about 150 mm, allowing for scale and application versatility. The depth of these dishes is also critical, usually measuring between 10 mm and 20 mm, optimizing the surface area for growth media and the space available for sample development without overcrowding.

The choice of material impacts their application: Glass Petri dishes can be sterilized and reused, which makes them suitable for high-temperature applications such as autoclaving, while plastic dishes are optimal for one-time use to prevent contamination and are often treated to enhance cell attachment and growth.

Moreover, some Petri dishes come with vents to facilitate gas exchange necessary for aerobic organisms, or they may feature grids and labels for easy sample identification and localization. Their design simplicity and clarity ensure that observations can be made directly, often under a microscope, without disturbing the cultured specimens. This makes Petri dishes indispensable in laboratories focusing on biological research, pharmaceutical testing, and educational demonstrations where observation and sterility are paramount.