Because during incubation moisture will form at the top of the petri dish. Inverting the dish prevents it from dropping into whatever you have in the petri dish.
If you leave them right-side up, the moisture in the agar will condense on the lid and the water will drip down on the surface of the agar causing your colonies to run together.
If left upright, condensation that forms on the lid will drip onto the plate, running the colonies together.
This inversion prevents moisture condensing on the surface of the plate. That would make a problem in that the growth on the plate would be "distorted" by the water making ID more difficult.
to prevent condenstion of the gel
A petri dish is a small glass plate used for, among other things, growing bacteria cultures to examine under a microscope.
The Petri dish is named after German bacteriologist Julius Richard Petri. Petri worked as a military physician for the German army and was assigned to a laboratory in Berlinβs Imperial Health Office in 1887. Building on methods such as the bell jar on a glass plate technique, Petri invented a culture dish very similar to the one we are familiar with today. He named the invention after himself and went on to write a 300-word paper about how to use the dish.
A Petri dish (or Petri plate or cell culture dish) is a shallow glass or plastic cylindricallidded dish that biologists use to culture cells[1]or small moss plants.[2
This inversion prevents moisture condensing on the surface of the plate. That would make a problem in that the growth on the plate would be "distorted" by the water making ID more difficult.
to prevent condenstion of the gel
This is to stop condensation from forming on the top of the lid. Condensation causes two problems (1) It will allow contamination to enter into the dish by moving accross the water film from the outside (2) It can create a tight seal and prevent oxygen entering the petri dish making it go anerobic.
Bacteria love to grow in moist damp places - if you haven't noticed, condensation causes water droplets to form on the top of the lid and if you incubated the plate with lid on top when the water runs down the sides of the plate it can easily contaminate your culture.
A shallow plate which is used in a science lab is known as a petri dish.
A petri dish is a small glass plate used for, among other things, growing bacteria cultures to examine under a microscope.
Carefully.
The clumps of growth are called colonies.
some sense
There is a lower chance of contamination from the air and the things surrounding it.
Advantages: 1. Counts only living cells 2. Standardized test - used worldwide Disadvantages: 1. 1-2 days of incubation 2. Melted, heated agar 3. Osmotic shock
If you meant to type "test plate" then what I think you are referring to is called a Petri dish.