Student Sample
February 25, 2013

The effect of antibiotics on bacterial growth

I. Problem – What is the effect of the antibiotics on the zone of inhibition?

II. Research – Antibiotics are natural or synthetic compounds designed to terminate any bacteria it is able to. They are mostly made by bacteria and different eukaryotic organisms such as plants, usually to protect the organism from infections caused by foreign bacteria. Antibiotics can also be manufactured by selecting a specific compound to target selected bacteria. They don’t have much effectiveness on viruses, however. The first antibiotic was discovered by Alexander Fleming in 1928.

III. Hypothesis – If the antibiotic is affective then the zone of the inhibition will increase in size.

IV. Materials –
Sterile agar plate
Sterile cotton swab
Forceps
Control Disks,x2
Permanent marker
Antibiotic sensitivity disks, (2 per student)
Disinfectant

V. Procedure –
1. First, put on any appropriate safety equipment needed for the experiment.
2. Secondly, next draw four 4ths of the circle of the petri dish with permanent marker and number them off, 1-4.
3. Third, get a Q- tip and dip the swab into the bacteria broth
4. Next, take the swab and rub on the desired forth of your fractioned petri dish
5.

VI. Data –
Picture or Drawing of Petri Dish
(insert picture or neatly draw your own of your lab group’s Petri Dish)

Antibiotic Resistance Results

Section
Antibiotic
Diameter (mm)
R,I,S
1

2

3

4

5

6

VII. Data Analysis – (note: answer in bold and use complete sentences)
1. What was the purpose using a sterile disc in the Petri dish?
Answer:

2. At what temperature