Evidence of the spread of bacteria

Principle

Microorganisms are ubiquitous, i.e. they are present everywhere around us. This fact can be proved by touching the objects that are to be examined in view of the presence of microorganisms against the sterile nutrient medium in a Petri dish and by incubating the plates afterwards. The easy working methods that are to be applied for this purpose are described based on the following examples.   

Benefits

• Experiment teaches all essential work techniques of microbiology.
• Complementary experiment available which uses these work techniques.

Tasks

• Provide evidence concerning the presence of microorganisms

1. in the air
2. on objects of daily use
3. on the skin
4. on insects

Learning objectives

• Disinfection
• Nutrient agar
• Sterility