The Effectiveness of Various Hand Sanitizers

My project is testing the effectiveness of different types of hand sanitizers. I am using simulated bacteria and a UV light to conduct my experiment.
Mia-Ruby Bassin
Grade 8


 The alcoholic gel hand sanitizer will kill the most germs. I think this because the alcohol in the sanitizer will destroy the cell membrane which is a lipid. The alcoholic gel hand sanitizer will break down the lipid coating of the cell which will make the germs easier to kill. Alcohol is a key ingredient in some hand sanitizers and it has been scientifically proven from many different studies that alcohol is the most effective substance at killing germs. 

Gel will adhere to the hand better than foam. Foam hand sanitizer is so light that it will evaporate before the hand is fully covered. 

Therefore, my hypothesis is that the alcoholic gel sanitizer will kill the most germs.





Bacteria are tiny single celled organisms. They can both benefit and harm our bodies. Bacteria can cause infections such as strep throat. Having good hygiene and eating fully cooked meats and thoroughly washed vegetables and fruit can prevent the harmful types of bacteria. 



Viruses can't live by themselves, they need a food source such as a living cell to stay alive. Viruses can survive for long periods of time on non-disinfected surfaces. They are always looking for new hosts and when they find a new host they will reproduce, . Viruses can give you illnesses such as the chicken pox and flu. 



Fungi are multi celled organisms. They can be found on land or in the water. Fungi can cause issues within the body such as athlete's foot. They can also be used to make medicine and are very nutritious and can be eaten. 



Protozoa are single celled organisms. They thrive on water and moisture. They can cause issues such as nausea and diarrhea.  

(Fifield, 2018)

Hand Sanitizer: Do's and Don'ts



  • Choose sanitizers with effective ingredients.
  • When picking an alcohol based sanitizer make sure it has more than 60% alcohol content.
  • Follow directions for proper use. 



  • Pick sanitizers with non-effective ingredients. 
  • Choose an alcoholic sanitizer with less than 60% alcohol content. 
  • Use sanitizers packaged in food or drink containers. 




  • Rub all over hands until the surface is completely dry
  • Keep out of eyes and month



  • Rinse off hands before dry
  • Swallow
  • Use to clean surfaces

(COVID-19 and Your Health, 2020)


Ingredients in Alcoholic Sanitizers


Emollients, polyacrylate, base, colours, fragrance- 1% of the sanitizer


Emollients- Protects the skin from the alcohols drying affects


Polyacrylate- Makes a gel with water


Base- Neutralizes the polyacrylates acidic effects and properties.


Colour- Gives the sanitizer its appearance


Fragrance- Gives the S=sanitizer it's smell 


Water- 40% of the sanitizer

Water acts as a carrier of the ingredients and a part of the hydrogel


Alcohol- 60% of the Sanitizer

The alcohol breaks up the lipid based coatings of bacteria and viruses to destroy them. 

(Howes, 2020)




Independent Variable

The independent variable in my experiment is...

My independent variable is the type of hand sanitizers I will be using while executing the experiment. This is my independent variable because it is the thing that I will be changing during my experiment.

Bath and Body Works Sanitizer

Non-Alcoholic Gel Sanitizer 

Alcoholic Gel Sanitizer

Foam Sanitizer


Controlled Variables

My constants are:

  • Same amount of time handwashing
  • Same brand and amount of soap
  • Same water temperature
  • Same grid (to count the amount of germs in each square)
  • Same measuring strategy
  • Same skin colour and texture; same persons hand 
  • Same Glo Germ gel
  • Same UV light


Responding Variable

My responding variable is:

The amount of surface area the germs are covering when sanitized with the different types of hand sanitizer. 





  1. Collect Materials and signed consent form. 
  2. Wash hands with soap and water for twenty seconds and dry hands thoroughly with a paper towel. 
  3. Draw a 5 by 5 cm square on the hand. 
  4. Using an eyedropper dollop 2 drops of simulated bacteria in the square. . 
  5. Rub in the product until no lotion remains; wait 15 minutes for the simulated bacteria to absorb into the hand. 
  6. Rub the sanitizer into the square and wait 5 minutes for the hand sanitizer to dry. 
  7. Use the UV light in a dark room to see the amount of germs on the hands. Take a picture of the hand.  
  8. Repeat steps 4-8 until all sanitizers are tested three times. 
  9. Print out the images (make sure they are all the same size)
  10. Put a grid over the image and draw a five by five square making sure to cover the previous square. 
  11. Count the amount of full squares, three quarter squares, half squares, quarter squares, and empty squares. (Make sure you use the same strategy for counting each time) 
  12. Add up all the fractions, convert the number to a decimal and then into a percentage. 
  13. Repeat steps 9-12 until every different type of sanitizer has their result. 
  14. Document the results. 



Trial 1

  • Foam: Looks brighter and whiter than the others
  • Non-Alcoholic Gel- Most of the germs are in the creases
  • Scented Bath and Body Works- More than others, less bright though
  • Alcoholic gel- Most germs in the creases

Trial 2

  • Foam: Looks brighter and whiter than the others (Like 1)
  • Non-Alcoholic Gel- more germs on the surface than last time
  • Scented Bath and Body Works- Germs brighter than trial 1
  • Alcoholic gel- Most germs in the creases

Trial 3

  • Foam: More germs visibly on the hand than first 2 trials
  • Non-Alcoholic Gel- Less germs than trials 1 and 2
  • Scented Bath and Body Works-  Brighter than 1 and 2
  • Alcoholic gel- Less germs that other 2





This bar graph is displaying the average percentage of 'germs' (simulated bacteria) remaining on the hand afer the use of various hand sanitizers. 



My project was testing to see which type of hand sanitizer kills the most germs. I was using simulated bacteria and a UV light to conduct my experiment and achieve reliable results. 
My hypothesis was correct. The alcohol based gel sanitizer killed the most germs. This is because the alcohol based gel sanitizer destroyed the lipid cell membrane which destroyed the germ cell. Alcohol based gel sanitizers kill the most germs. We should always be using them to keep us safe. 



Practical Application

Hygiene is very important, especially now. With COVID-19 out there we want to make sure that we are staying as safe as possible. Viruses and bacteria act very similarly, this is why my project is applicable now, with COVID-19 as well as many years in the future when there could be another pandemic or illness, involving viruses or bacteria. While hand washing is the most effective way of removing germs and cleaning hands we can't carry a sink with us wherever we go. This issue is resolved with hand sanitizer. However, we want to make sure we are using proper sanitizers that will effectively remove germs. 

My project is perfect for this front. It is ineffective, as I learned from my experiment, to carry around Bath and Body Works hand sanitizers that smell good and look pretty but leave 94% of germs on the hand even after sanitizing. This is why we should be using alcohol based sanitizers whenever we are on the go and need to keep ourselves safe. 


Sources Of Error

Sources of Error

The possible sources of error in my project are: 

  • I may have put more sanitizer when I was testing one type of hand sanitizer than another.
  • I may have counted or calculated incorrectly. 
  • The subjects hand may not have been completely clean when I was applying the simulated bacteria. 
  • The simulated bacteria could have been unevenly spread or rubbed in. 


Fifield, K., 2018. What are 'germs' anyway?. [online] MSU Extension. Available at: <https://www.canr.msu.edu/news/what_are_germs_anyway> [Accessed 13 February 2021]. This site told me what germs are. It also told me about the four different types of germs. This will help me with my project because I am seeing which hand sanitizer will kill the most germs. In order to understand how best to kill germs I first need to understand what they are.

Centers for Disease Control and Prevention. 2020. COVID-19 and Your Health. [online] Available at: <https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/hand-sanitizer.html> [Accessed 17 February 2021]. This site explained how to select and use hand sanitizer properly. This will help me with selecting the different types of hand sanitizer I will be testing. It will also help me use it properly when I am testing it.

Howes, L., 2020. What is hand sanitizer, and does it keep your hands germ-free?. [online] Cen.acs.org. Available at: <https://cen.acs.org/articles/98/i12/hand-sanitizer-does-keep-hands.html> [Accessed 19 March 2021].  This site helped me understand the ingredients and properties of hand sanitizer. It will help me understand what the sanitizer I'm testing is made up of. Which will therefore give me a better general knowledge when I'm doing the experiment. 




I would like to thank my science fair coordinator for assisting me throughout my project. I would also like to thank the teacher who was my subject. This project truly wouldn't have been possible without your hand and your patience.