Download School Swab Formal Lab

Bacteria Lab Guide CLASS SET
This lab is meant to be personalized by each lab group.
Purpose:
To test the effects of antibiotics on bacteria. Be specific.
Background:
Regular:






What are bacteria?
Where are bacteria found?
How are bacterial beneficial? Give examples.
How are bacteria harmful? Give examples.
Common bacteria?
Ways to avoid infection?
Pre AP:







What are bacteria?
Where are bacteria found?
How are bacterial beneficial? Give examples.
How are bacteria harmful? Give examples.
Common bacteria?
Ways to avoid infection?
Aseptic Technique? Importance, basic steps, etc.
Hypothesis:
: If (independent or dependent variable)……..
…………….then (dependent or independent variable)
Materials:










Petri dish (1 per lab group)
Sterile nutrient agar
Untreated discs
Antibiotic discs
tweezer
Sterile swabs (1 per lab group)
10% bleach solution
Distilled water
Sharpie
Tape
Procedure:
1. Obtain a prepared Petri dish from your teacher.
2. Divide up the Petri dish with the marker based on your experiment. Write
only on the bottom of the dish.
3. Label the Petri dish, correctly, with name, date, bacteria and antibiotic(s).
4. Remove the sterile swab from the package. Gently touch the cotton tip to
the bacteria on the starter plate. Remove a small quantity of bacteria.
5. Open the Petri dish just enough to inoculate the agar with bacteria.
6. Close the Petri dish.
7. Drop the used swab in the bleach solution cotton tip down.
8. Opening the Petri dish just enough to get the tweezer inside, use the
tweezer to place an untreated disc on the designated section of agar.
9. Use the tweezer to remove an antibiotic disc from the dispenser.
10. Immediately place the disc in the center of the designated section.
11. Close the petri dish.
12. Repeat steps 8-10 if using more than one antibiotic.
13. Tape dish shut and store in designated location bottom side up.
14. Record both qualitative and quantitative observations every two days.
Data:



Should include descriptions and drawings of shape, color, and
number of colonies FOR EVERY OBSERVATION.
Should include descriptions and drawings of anything else
growing in the plate.
Any changes should be noted
Analysis:


Trends in growth, number of colonies as they appear, changes
in color, shape, etc.
Independent variable, dependent variable, control,
Conclusion:







Statement of the problem
Support or reject hypothesis
Data to explain why hypothesis was supported or rejected
Possible sources of error
Conclusions about the location, frequency, occurrence, etc. of
common bacteria
Lessons learned from this experiment
Further questions