My question for this experiment is which cleaning method soap, sanitizer or water works the best on dirty hands .My manipulated variable is soap sanitizer and water. My dependent variable is dirt food and grease. Lastly my controlled variable is the amount of pumps taken for soap and sanitizer. If I wash my hands with soap ,sanitizer and water then I can see which works better because I want to figure out which one removes germs from my hands.

My experiment tests which cleaning method soap , sanitizer or water works best on dirty hands .I predicted that soap would work more effectively than sanitizer and water by putting glow in the dark powder on my hands while cleaning them with soap sanitizer or water and later on closing the lights to see the remaining residue. While I was doing my background research I found out that soap takes off germs and dirt from your hand by using amphiphilic molecules .In conclusion soap significantly had the most effect in cleaning my hands as they not only kill microorganisms but also remove them from the skin surface.

Based on the topic Soap vs Water vs Sanitizer the manipulated variable is the soap, water and the sanitizer as I am controlling it. For the Dependent/Responding variable is the dirt, food and grease and lastly for the controlled variable it is the Surface type on my hands, the amount of the dirt food or grease plus the cleaning time.

1.I spread glow in the dark powder in a pan and mix it with vaseline to create a thick paste 2.Then I put the paste(Glow in the dark powder) on both front and back sides of my hand 3.Next I put  Grease,food and dirt one by one to test it 4.Wash with Soap,Water and Sanitizer for 20 sec each and dried my hands for 5 sec  5.Lastly I took a picture of the residue left after cleaning my hands in a dark environment. 

Soap observation-While cleaning my hand I noticed my hands consistently clean throughout my experiment. Sanitizer observation-There were lots of strokes of the germ powder still on my hand Water observation-

After cleaning my hands saw under the glow in the dark powder how much residue was left .I observed that the water worked so much more efficiently rather than water and sanitizer as soap and water (together) removed more dirt than water (alone) and sanitizer. By keeping the amount of germs and cleaning time the same I know the results were caused by the cleaner itself.

In conclusion based on my experiment sanitizer does not kill all types of germs and water alone only reduces 23% of germs. So soap significantly had the most effect in cleaning my hands as they not only kill microorganisms but also remove them from the skin surface.This matters as it can help you decide when it is the right time to use Soap,Sanitizer or water.

This applies in the real world as it shows how different cleaning methods work. It helps us realize that soap and water (together) work better rather than sanitizer and water.

-Could of dried my hands for longer than 3 sec

-Measuring the amount of germs

-Maybe could of tried trials.

-Next time use try different ways to dry my hands

Petruzzello\, Mellisa. “How Does Soap Work? | Britannica.” Britannica , www.britannica.com/story/how-does-soap-work. Accessed 23 Feb. 2026.

Rosenthal, Alex. “Which Is Better: Soap or Hand Sanitizer? .” YouTube, 2021, www.youtube.com/watch?v=x7KKkElpyKQ&t=215s. Accessed 23 Feb. 2026.

I sincerely acknowledge and appreciate the guidance, support, and encouragement of my family. Their valuable patience, and constant motivation have been instrumental in the successful completion of this work.