Hand Washing Lab Emma Williams September 11 2013 Biology Lab 101 423 Honor Code I pledge that no unauthorized assistance has been given or received in the completion of this work Experiments described were performed by me and or my lab group and this write up is entirely my own creative work Introduction I II This experiment is used to test the effectiveness of various soap brands The soaps being tested are the Harris Teeter Antibacterial Liquid Soap and Dial Gold hand soap with moisturizer The purpose of this experiment is to test which soap kills the most bacteria In this experiment the control variable is water and the dependent variables are the two soap brands Since the Harris Teeter brand is antibacterial it is more likely to kill the bacteria than Dial Gold hand soap with moisturizer which is not antibacterial When comparing the Harris Teeter Antibacterial Liquid Soap and Dial hand soap with moisturizer the Harris Teeter Antibacterial Liquid Soap will kill more than the Dial hand soap with moisturizer III IV V VI Materials and Methods I 3 petri dishes filled with solidified agar Harris Teeter Antibacterial Liquid Soap Dial Gold hand soap with moisturizer Water Sealing tape Sharpie marker At least one partner Using a sharpie label the bottom side of your petri dish by drawing a line down the middle and write a before for before you wash your hand on one side and after for after you wash your hand on the other side On the before side of each dish lightly press three unwashed fingers into the agar There should be a visible trace of your finger prints left on the agar Each partner will test one of the variables The partner testing the control water will wash their hands with only water for 30 seconds The partner testing the Harris Teeter brand will wash their hands with this soap for 30 seconds and the same for the partner testing the Dial Gold Once your hands are washed each partner will press three clean fingers into the side labeled after on each dish according to the type Next place the lids of the petri dishes on each one and seal each with a strip of sealing tape Store the petri dishes at room temperature for a week then refrigerate for a week Observe the growth of the bacteria over the course of two weeks II III IV V VI Results Harris Teeter brand Before Side o Where the three fingers were pressed into the agar there are two small patches of bacteria cultures o They are fairly small circles of bacteria that look like dots o The spots are a yellow color and the biggest one is about 1mm wide and the rest are smaller than that After Side o The growth on the after side is more spread out but broken up into smaller dots instead of two solid dots o The smaller dots are an off white color Dial Gold brand Before Side o The before side has a large white spot about 1 inch wide with a small dark green spot inside it which is about 1mm in the middle of that side o Near this large spot is are medium white spots measuring about 2mm o Also near the larger spot are smaller sized yellow clusters measuring about 1mm After Side o The after side has two clumps of smaller dots that are off white and yellow o The clumps of dots are about 3mm wide Water control Before Side o On the dirty side of this dish is a large white growth that is 2cm in diameter o Next to this there are two more white growths measuring 1mm o On the bottom half of this side there is one more yellow growth measuring 2mm After Side o On the clean side there are three small patches of tiny clusters of growth that are a yellow color o The spots in this cluster measure about 1mm in diameter each o Next to this clusters are two smaller yellow spots measuring 1mm Discussion I II The data collected from the petri dishes in this experiment cannot be used to support the hypothesis that was proposed On the Harris Teeter brand dish the bacteria from the before side had been mostly washed off the hands due to the lack of bacteria grown on the after side III IV V VI VII VIII IX X XI XII This makes it easy to tell that the soap was effective in removing bacteria since it is clear how much bacteria grew on the after side The Dial Gold on the other hand has a distinct difference between the before and after sides of the dishes The disappearance of the large white and green growth on the before side of the dish signifies that the soap was effective in removing bacteria Although the after side of the dish still has clusters of bacteria it is a great improvement from the dense growth that occurred on the dirty side of the dish In comparison to these two dishes that tested soap one can look at the control dish water and compare the results to see what would happen if no soap at all was used There was no large difference between the before and after sides of the dish since the water does not contain any substance designed to remove bacteria This is what was expected to happen in the control dish From the results collected the experiment does not support hypothesis that the Harris Teeter would remove the most bacteria Even though the Harris Teeter brand removed some bacteria it is clear that the Dial Gold brand removed more bacteria than the Harris Teeter brand and the control This experiment is a helpful way to interpret which kinds of soaps work the best at removing bacteria
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