Biology+Method

Variables:
//Independent// -Swimming pool water collected from three different locations. //Dependent// -The amount of Staphylococcus epidermidis survives after the contact with swimming pool water. //Controlled// -Staphylococcus epidermidis collected from human skin (one person) - Bacteria in the swimming pool initially -Time of leaving the bacterias in the swimming pool water.

Materials:
- 3 clean empty bottles, for collecting swimming pool water. - 7 Agar plates - Microscope with oil immersion lens - Gram stain materials (Crystal violet, Grams Iodine, 95% ethinol or Alcohol/ Acetone, and Safranin) - Clean cotton swabs - Bunsen burner - Lighter - Microscope slides - Wooden clips - Pipette - Immersion oil - Nichrome wire inoculation loop - Beakers

Figure1. Collected swimming pool water

Figure2. Microscope used to observe bacteria

Figure3. Gram Stain materials

Procedure:
__Part 1 (Preparing):__ 1. Prepare 7 agar plates for growing the bacterias 2. Collect 3 bottles of swimming pool water from three different pools.

__Part 2 (Growing bacterias):__ 1. Take out some sample from each bottle by using clean cotton swabs. 2. Swab them onto the agar plates and label the dishes. 3. Leave them aside for the bacterias to grow. 4. Using the same steps, grow bacteria from human skin. 5. After the bacterias had grown, take some bacteria from the "human skin agar plate" and mix them with some fresh swimming pool water from the bottles. Then leave them aside for 1hr. 6. After 1 hour, use those swimming pool water to grow bacteria.

__Part 3 (Gram stain):__ 1. When bacterias show up on the agar plates, the Gram staining procedures can begin. 2. Gram stain the bacterias from each plate and then observe under the microscope. Record the data, and at the end compare the results.