Handwashing Experiment

Do you wash your hands? Do you use soap? Only 68% of Americans wash their hands after using the restroom. Each year, nearly 22 million school days are lost to the common cold. Thoroughly washing hands is the single most important thing students can do to keep from getting sick or to keep from infecting others.

Questions Which form of hand washing will be most effective at eliminating bacterial growth? Hypothesis: Which side of the public restroom door contains the least amount of bacteria?

Procedure Obtain 2 agar plates and label them as follows: Don’t forget to put your period and group # inside outside URT ULT WRT ULT

Determine which handwashing method your group will use Determine which handwashing method your group will use. You can choose from the following: tap water, regular soap, antibacterial soap, hand sanitizer. Write the method you use on your agar plate. Gently press your unwashed left thumb (ULT) into both the upper and lower quadrants. Press the unwashed right thumb (URT) onto the agar. Wash your hands according to the method you are testing. All students should wash hands for 20 seconds. After washing and drying with a paper towel, press washed right thumb (WRT) onto the agar. Decide which public restroom door to test. Take two cotton swabs, a tube of distilled water, and the labeled restroom agar plate to that restroom door. Swab the inside door knob that is most likely touched and gently streak the agar with swab. Repeat for outside knob with other swab.

Discussion Questions Do your results support your hypothesis? Explain. Why did you do your left unwashed thumbprint twice? Based on your class data, which method of handwashing is the most effective? Explain. Based on your class data, which side of the bathroom door contains the least amount of bacteria? Explain. What have you learned from doing this experiment?