Many times there is terminology that you hear or read but you do not know what it is.
What is a Petri Dish?
The Petri dish or capsule is a round-shaped container, it can be made of glass or plastic, with a cover of the same shape as the plate, this cover is a little larger in terms of its diameter, to be able to place it on top and close the container, although not in a hermetic manner. It belongs to the collection of glass materials. It is used in micro-biology to grow cells, observe seed germination, or examine certain behavior of small animals.
This plate was built in 1877 by Julius Richard Petri , a German-born bacteriologist, when he was working as Robert Koch’s assistant. It was for microbiology a revolutionary invention since by means of these plates it has been possible to isolate different organisms that cause diseases such as Diphtheria or Cholera. From this, ways to combat these diseases have been found a posteriori.
What is the Petri Dish for?
It is used in laboratories generally to cultivate bacteria, molds and other types of microorganisms, the bottom is usually covered with different culture media, depending on the microorganism that you want to cultivate.
If it is desired to look at colonies, during its incubation time of the microorganism seeded on the plate, it is kept upside down, resting on the lid. In this way, the agar remains in the upper sector and when the water vapor generated by said microorganisms by their metabolism condenses, it falls on the lid, preventing the microorganisms from being diluted, remaining fixed to the substrate.