Reason of why our bacteria grow in big patches.

  This week, we have done the experiment of growing bacteria. Through observation, instead of bacteria having there own colonies, our bacteria formed one colony by themselves -_-. After a pile of research, I came up with the report of why is our grown bacteria forming a huge patch of colony.

 Reason No.1: uncontrolled environment. It is not hard to know that when we are doing the project, the lab was very noisy, many people were talking while doing the project, this caused the bacteria in our mouth to travel through air into the cotton butt, or even the agar gel, the result would not be accurate as there should be a mixture of the bacteria in our saliva and the bacteria from the assigned location.

 Reason No.2: problem in sequence/process of growing bacteria.
  This problem would be a consistent problem caused by unspecific orders and errors in actions.

  (1a) Unspecific order No.1 : The number of swipes on the agar gel. The number of swipes on the agar gel was not specifically given by the instructed teacher,causing many people to overswipe the agar gel, which could easily cause a patch to happen. when a whole area is swiped, the bacteria just have to go through the moist layer of the agar gel to be luminous.
  (1b) Unspecific order No.2 : The strength of each swipes. The strength of each swipe is such important that is determined how deep in the agar gel is the bacterias planted, and thus this would also determined it could be beautiful colonies or just a patch.
  (2a) Sequence error No.1 : the dropping of cotton butts, by my observation, many people dropped the cotton butt due to improper handling, this causes the results to be very inaccurate.As the bacteria in the petri dish could include the area assigned and the area the cotton butt dropped.
  (2b) Sequence error No.2 : the treatment of coverage of the petri dish.:When many people swiped the agar gel, the cover of the petri dish was opened, causing the bacteria in the air to enter the sterilised environment and causing the results to be inaccurate.

  Due to the above reasons, many of our experiment result was shown inaccurate, wish we could improve some of the above condition and have a better bacteria growth. :)

This is a picture of a well grown bacteria petri dish.

Have fun and see you next blog. ------Michael 2 humility group 10