Biology - HOT Science Lab

Student
bactericide that is more effective at inhibiting the strain‘s growth than a bactericide that creates a
smaller zone of inhibition.
Purpose or Problem Statement: What are the effects of antiseptics, antibiotics, and
disinfectants on bacterial growth
Safety:
Wear goggles and an apron throughout this lab.
Do not touch your face until you have thoroughly washed your hands with soap.
Wash your hands for a minimum of 30 seconds (count in your head!) with soap and
running water before leaving lab.
Use aseptic technique to avoid contamination of your culture and environment.
Many antimicrobials are caustic or toxic; use caution when working with these reagents.
No eating, drinking, gum-chewing, or horseplay in the lab!
Vocabulary: bacterial lawn, antiseptic, disinfectant, antibiotic, inoculation, zones of inhibition
Hypothesis: Develop a hypothesis for this lab based on the reagents you are assigned to use
in the procedure. It should be written as an ―If – Then – Because‖ statement.
Materials (per group):
1 agar plate
Sample of bacteria
Inoculating loop or cotton swab
Forceps
Tape
1 wax pencil/Sharpie
1 metric ruler
Distilled water
1Blank paper disk
1 antibiotic disk (previously soaked)
in penicillin
1 disinfectant disk (previously
soaked) in disinfectant
1 antiseptic disk (previously soaked)
in antiseptic
Procedures:
Day 1: Keep petri dish closed at all times except when inoculating and placing disks in
quadrants!!
1. On the outside bottom of the petri dish, close to the edge of the dish, write the names of
you and your partner(s) and your class period in small letters with the Sharpie/wax pencil.
2. On the outside bottom, draw lines to divide the dish into quadrants and number them 1,
2, 3, and 4.
Biology HSL Page 290
Curriculum and Instruction