Which soap eliminates the most bacteria of off your hands?

Question: Which soap, Softsoap, Bath and Body Works soap, or Simple Pleasures, eliminates the most bacteria off of your hands?

Hypothesis: I hypothesize that the Bath and Body Works soap will clean off the most bacteria because of the anti-bacterial crystals in them (jelly, bouncy, round things.)

Procedure:

1. Gather my soaps (Softsoap, Simple Pleasures, Bath and Body Works soap)

2. Wash hands with 4 ML of soap.

3. Wash hands under water for the same amount of time with each soap and the same motions of my hands for each soap.

4. Swab hands and put on petri dish.

5. Wait a couple of days then measure how much bacteria is in each petri dish.

6. Conclude whichever grows the least amount of bacteria is the best cleansing soap.

Data: (bar graph in link below)

Amount of Bacteria Colonies Left After Each Hand Wash

Conclusion: This experiment’s results did not prove my hypothesis. I predicted that Bath & Body Works soap would clear the most bacteria off of my hands, but it turned out that Simple Pleasures soap eliminated the most bacteria. This conclusion could possibly be an effect of how hot or cold the water was each time my hands were washed. Maybe I should have used the exact same temperature of water when I washed my hands. To keep accuracy, I used the same amount of soap (1.5 milliliters), put the same amount of mud on my hands, used the same hand motions, and rinsed my hands for the same amount of time during each hand wash. I believe the outcome of this test was on target because the variables, the mud and how much I scrubbed my hands, were controlled. After performing this experiment I learned that experimenting with bacteria can be challenging but also fun.

Abstract:

Filthy Fingers

Which soap eliminates the most bacteria off of your hands?

Julia Sorensen

I wanted to investigate which brand of soap, Bath and Body Works soap, Simple Pleasures soap, or Dial soap, will eliminate the most bacteria off of your hands. I hypothesized that the Bath and Body Works brand would clean off the most bacteria because it contains small anti-bacterial crystals.

Permission was obtained to proceed with this experiment. Testing was performed in the school lab so that nobody at home was infected by the bacteria. To make sure the investigator’s hands were equally dirty each time they washed them, she dipped them in a pile of mud. The first soap tested was Bath and Body Works soap in the smell of Wild Passion Flower. Using the same hand motions, the investigator rolled her hands around with the soap then put it under water. This was repeated five times for each of the three washes with the Bath and Body Works soap. After each hand wash, the investigator put her index finger on a petri dish to transfer what bacteria remained on the hand. The investigator repeated these same steps when experimenting with the other two soaps; Dial and Simple Pleasures soap. After six days in an incubator, the petri dishes were ready to be checked for colonies of bacteria. To check how many colonies were on each plate, the investigator hand counted each of them.

The data showed that Simple Pleasures soap eliminated the most bacteria off of my hands, with an average of 46.4 colonies transferred onto the petri dishes. The average amount of bacteria colonies transferred onto the petri dish for Bath and Body Works soap was 49.7. Dial soap, which eliminated the least amount of bacteria off of my hands, had an average of 69 colonies of bacteria left transferred onto the petri dish.

The results of this experiment proved my hypothesis wrong. Simple Pleasures soap, rather than Bath and Body Works soap, eliminated the most bacteria off of my hands after washing them. This conclusion may be an effect of how hot or cold the water was each time my hands were washed. Perhaps the temperature of the water should have been exactly the same for each hand wash. Accuracy in this experiment was kept by using the same amount of soap (1.5 milliliters), putting the same amount of mud on my hands, using the same hand motions, and rinsing my hands for the same amount of time during each hand wash. By doing this experiment I have learned that working with bacteria can be fun but can also be challenging.

Pictures: (are also in the links below)