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Spread the Soap, Not the Germs

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Do you wash your hands? You should— it's the best way to prevent the spread of germs. But germs can be tricky; they find nooks and crannies to hide in, so it takes good hand-washing technique to get rid of them. In this science project, you'll investigate which parts of the hand are the most difficult to wash germs off of.


Areas of Science
Time Required
Average (6-10 days)
Material Availability
To do this science project you'll need to order Glo GermTM over the Internet. See the Materials and Equipment section for more details.
Very Low (under $20)
No issues
Sandra Slutz, PhD, Science Buddies

Glo GermTM is a trademark of Glo Germ Company.


In this science project, you will investigate which parts of the hand are the most difficult to wash germs off of.


"Cough, cough, cough! Achoo!"

"Oh no, stay away from me! I don't want your germs!"

You may know that germs are something you don't want, and that they can be spread from one person to another, especially by coughing and sneezing. But what are germs? Germs are tiny little organisms, too small to be seen without a microscope. Not all germs make us sick, but many are the causes of a wide variety of common illnesses. For example, one type of germ, viruses, cause the flu and can also cause us to get a cold. Viruses need to be inside a human, animal, or plant to grow and multiply. Unlike viruses, bacteria, another type of germ, can live on their own. They're found in many different environments, but some prefer to live inside humans and these sometimes cause illnesses such as food poisoning or a really bad sore throat called strep throat.

Everyone gets sick sometimes, and it is pretty hard to avoid every germ all the time, but you can prevent the spread of germs by carefully washing your hands. Germs are everywhere and when we touch things, we get germs on our hands. Then we touch other things and those germs spread from object to object and person to person.

According to health professionals, carefully washing your hands for 20 seconds (that's about as long as it takes to sing "Happy Birthday" twice) in warm water with soap will eliminate most germs and keep you healthier. But germs can be tricky; they find nooks and crannies to hide in, so it takes good hand-washing technique to get rid of them. In this science project, you'll use Glo Germ to investigate which parts of the hand are the most difficult to wash germs off of.

Terms and Concepts



Good information about germs and hand washing can be found at these websites:

  • Nemours Foundation. (May 2006). What Are Germs?. Retrieved March 28, 2008.
  • Department of Health and Human Services at the Centers for Disease Control and Prevention. (2008, February 18). Clean Hands Save Lives!. Retrieved March 28, 2008.

More information about Glo Germ can be found at their company website:

  • Glo Germ. (n.d.). Glo Germ. Retrieved March 28, 2008.

Materials and Equipment

Experimental Procedure

For this science project, follow the experimental procedure below with as many volunteers as you can.

  1. Applying the Glo Germ Gel
    1. Squeeze a nickel-sized amount of the Glo Germ gel on the palms of your volunteers' hands.
    2. Have your volunteers rub their hands together as if they were applying hand lotion. Make sure they completely cover their hands, including around their fingernails and in between their fingers.
  2. Once the Glo Germ gel has been applied, have your volunteers wash their hands with soap and water. Even though they now know where the Glo Germ is on their hands, since you directed them to completely cover their hands, fingernails, and in-between their fingers, be sure they wash their hands as they normally would.
  3. Now shine the ultraviolet pen light on their hands. Look carefully for any "glowing germs."
    1. Doing this step in a darkened room or closet makes it easier to see.
    2. Are there any? Where are they located— on the palms, fingers, back of hands, around the fingernails? In your lab notebook, make a data table, like the one below, showing all the possible parts of the hand that germs might be found on. For each test subject, insert a check mark for each part of the hand where you observed "germs" after hand washing.
Side-by-side photos of the front and back of a hand labeled with fingers, palm, between fingers and fingernails
These images show different parts of the hand where you might find germs.

Test Subject Palm Back of Hands Fingers Between Fingers Around Fingernails
  1. After you've done this procedure with all your test subjects, add the number of check marks for each column in your data table. How many people had "germs" left on each part of their hand? Make a bar graph showing your results. Which hand part was least likely to get clean? What conclusions can you draw about the effectiveness of people's hand-washing techniques?

Explore More!

Interested in the science behind viral outbreaks? Check out Coronavirus.

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Ask an Expert

Do you have specific questions about your science project? Our team of volunteer scientists can help. Our Experts won't do the work for you, but they will make suggestions, offer guidance, and help you troubleshoot.

Global Connections

The United Nation's Sustainable Development Goals (UNSDGs) are a blueprint to achieve a better and more sustainable future for all.
This project explores topics key to Good Health and Well-Being: Ensure healthy lives and promote well-being for all at all ages.


  • Does the length of time spent washing your hands impact how many germs are left after hand washing? Repeat the science project above, this time using a stopwatch and having your volunteers wash their hands for different lengths of time, like 10, 20, and 40 seconds. Remember to have at least three volunteers participate in each time trial.
  • Once they're on your hands where do the germs go? Do they get transferred to other objects? Design an experiment, using the Glo Germ, to examine where the "glowing germs" go.
  • Try repeating the experiment to find out whether covering your nose with your elbow when you sneeze spreads fewer germs than covering your nose with your hands.


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General citation information is provided here. Be sure to check the formatting, including capitalization, for the method you are using and update your citation, as needed.

MLA Style

Slutz, Sandra. "Spread the Soap, Not the Germs." Science Buddies, 15 Apr. 2022, https://www.sciencebuddies.org/science-fair-projects/project-ideas/MicroBio_p018/microbiology/soap-wash-away-germs?from=Blog. Accessed 30 Sep. 2023.

APA Style

Slutz, S. (2022, April 15). Spread the Soap, Not the Germs. Retrieved from https://www.sciencebuddies.org/science-fair-projects/project-ideas/MicroBio_p018/microbiology/soap-wash-away-germs?from=Blog

Last edit date: 2022-04-15
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