Why round shaped petriplates are most commonly used in microbiology?

Julius Richard petri was a german bacteriologist who is generally credited with inventing petridish while working as an assistant to pioneering bacteriologist Robert Koch.

Different shapes of petriplates are available in market but most commonly round plates are used in microbiology because liquids are less likely to conglomerate around smooth surfaces than corners. During sample testing, sample should be properly mixed and distributed in the media in petriplate for proper colony counting and if petriplates are round then you can easily swirl around liquids without having sample catch around the corners or agitating the liquid too much. Another reason is that round shape petriplates are easy to handle and clean. That's why round petriplates are most commonly used in microbiology.

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