A growth medium or culture medium is a solid, liquid, or semi-solid designed to support the growth of a population of microorganisms or cells via the process of cell proliferation or small plants like the moss Physcomitrella patens. Different types of media are used for growing different types of cells.
An agar plate – an example of a bacterial growth medium*: Specifically, it is a streak plate; the orange lines and dots are formed by bacterial colonies.
US Food and Drug Administration scientist tests for Salmonella
A culture of salmonella bacteria
Physcomitrella patens plants growing axenically on agar plates (Petri dish, 9 cm diameter)
A microorganism, or microbe, is an organism of microscopic size, which may exist in its single-celled form or as a colony of cells.
A cluster of Escherichia coli bacteria magnified 10,000 times
Mahavira postulated the existence of microscopic creatures in the 6th century BC
Antonie van Leeuwenhoek was the first to study microscopic organisms.
Lazzaro Spallanzani showed that boiling a broth stopped it from decaying.