Required practical

• We grow bacteria in a petri dish of agar jelly. This has the nutrients bacteria cells need to grow. They are to be grown at 25 degrees Celsius.
• 1. Soak filter paper disks in a variety of solutions to test the effectiveness of killing bacteria
  2. Put the paper into the agar plate in different places to see the effectiveness of the solutions at killing bacteria
  3. Measure the clear area around the soaked filter paper disks because the size of clear zone indicates the effect of the substance tested on the growth of the specific bacterium
• The clear area in the practical is called the zone of inhibition.
• The independent variable are the types of solutions soaked on the filter paper.
• The control variable is the type of bacterium in the agar plate and the temperature the bacteria is grown at.
• The dependant variable is the zone of inhibition or clear zone around the soaked filter paper.