Jeremy

Jeremy Chu Lab Science9

Planning an Experiment- killing bacteria/ preventing growth of bacteria

Question for investigation: When we use alcohol, tooth paste....to kill bacteria, will the bacteria have the immunity from the alcohol, tooth paste. So that the bacteria will not die, although adding the alcohol, or tooth paste.

Independent variable: The liquid that we are going to use for killing the bacteria. This will measured by a beaker.

Dependent variable: The size and amount of the bacteria. This will be measured with a ruler.

Varaiables held constant: The amount of liquid that you use for klilling the bacteria, and the amount of bacteria initially wiped onto the plate.

List of materials: Cotton swab Agars (wipe bacteria in) Ruler Beaker Disk paper Microscope (to check the bacterias after putting the liquid, and before putting the liquid) Liquids (bleach, soap, tooth paste, alcohol, ......)

Sketch:

Procedure: Soak the disk paper into different liquids( shampoo, ammonia, tooth paste....) Place the disk paper into the agar. Measure the weight of the agar. After some time, some of the bacteria will be dead on the agar plate. Weight the agar again.

Expectations: To see will if the weight of the agar will be less after placing the disk paper. And if the bacterias are still grwoing, that means the bacteria have the immunity from the liquid.