Bacteria Lab Write-Up Jianna Liu
Purpose: The purpose of this lab is to find out which substance, alcohol, antibacterial soap, water, or hydrogen peroxide, is the best at preventing the growth of bacteria.
Hypothesis: Antibacterial soap will be the best because soap is a substance that people use to wash their hands because it takes away the germs. Even the name, antibacterial soap, suggests that it fights off bacteria. Hydrogen peroxide is second because it is used to kill off cells on wounds and is poisonous. Rubbing alcohol will be third because medical professionals use it to sterilize skin, but it doesn’t kill much bacteria. Lastly, fourth will be water because without anything to help it, water cannot do anything. For example, if you wash your hands and you do not use any soap, none of the germs on your hand will be cleaned.
Materials: The materials we used in this lab were a petri dish with agar, forceps, water, alcohol, hydrogen peroxide, antibacterial soap, filter paper disc, tape, and a permanent marker.
Procedure: We started this lab on May 12, 2014. Using a permanent marker on the bottom of the dish, we divided it into 4 sections. We labeled the sections, W (water), A (alcohol), S (soap), and HP (hydrogen peroxide). Then, we labeled the perimeter of our dish with our initials and class period. Kyra rubbed her fingers across the surface of the table for 30 seconds (you can also use the bottom of your shoes, the door knob, etc.) Then, Christine lifted the lid off of the petri dish so that Kyra could gently rub her finger across the entire surface of agar. We were careful not to puncture the agar. Then, we replaced the lid. We wet one disc in each liquid using the forceps (shaking excess liquid off disk), and then placed the disc on the agar in the middle of the appropriate section. Soon, we closed the lid. Afterwards, we turned the agar dish into our teacher for incubation.
Results: We saw the petri dish again on...
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