Our Hypothesis:

We anticipate that simply shaking your hands dry is the cleanest method of drying your hands. This is because when drying your hands, the hand dryers have lots of bacteria that have been pulled in with the air, and they are just blown onto our hands making them more dirty. We predict that paper towels aren’t the best solution either. People sometimes touch paper towels while getting their own. So we believe shaking our hands dry is the most sanitary way of drying your hands.

How Do Hand Dryers Get Dirty & Spread Bacteria?:

According to an article by Harvard Health Blog, hot-air hand dryers in public restrooms pull bacteria from the air and dump them onto newly washed hands.

How Does Bacteria Spread?:

Bacteria can be spread from one person to another through food, air, water, and vectors. Bacteria cells have parts, they have one known as the flagellum which has 3 parts—the motor, hook, and filament. The movement of the filament allows the bacteria to control its movement around our environment.

The Main Question:

According to research, Public hand dryers spread germs and only add to the number of bacteria on your hands. The question is, what is the best method to dry our hands while keeping them clean?

The Purpose Of Our Project:

The purpose of our project is to find out if using a hand dryer and/or a paper towel is sanitary. After all, the purpose of washing your hands is to clean them. Leaving no excuse for unwanted bacteria. To find out if hand dryers and paper towels harbour unwanted bacteria, we will be experimenting using Petri dishes.

Independent Variables- The bacteria growth in Petri dishes

Dependent Variables- Petri- Dishes, Hands, Hand Dryer, Paper Towel

Controlled Variables- Petri Dishes, Temperature, Hands, Number of times the hands are washed, soap

The Procedure of Our Experiment:

Before our experiment, we had to make the agar for the Petri dishes.

1. We ordered the agar kit online for our experiment

2. Next we boiled the powder and made our agar solution. The agar had to be boiled in water on low heat for 5-10 minutes.

3. After that, we poured the solution into the dishes. We made sure all the dishes had the same amount of agar. we let the agar set for a day.

4.  Once the dishes were ready and the agar was set, we swabbed our items. the items included:

                                                                                            -Kleenex

                                                                                            -Paper towel

                                                                                            -Hand dryers

                                                                                            -Our hands after we shook them dry.

5. We waited 5 days for the bacteria to grow inside the petri dishes. We left the dishes in a desk drawer and tried to not open the drawer at all.

6. Once the experiment was finally done, we analyzed the results.

The shaken dry dish #1 was filled with bacteria, while #2 and #3 had little to none.

The dried with hand dryer dishes #2 and #3 were all very clean.

#1 had bacteria but it was very little.

All of the paper towel dishes had a lot of bacteria, but they were nothing compared to the Kleenex. The Kleenex dishes were the ones with the most bacteria in our opinion.

Throughout our experiment, we analyzed it with some specific expectations. We first needed to analyze the growth of bacteria in each of our Petri dishes to conclude which might be the cleanest overall— we also needed to find out which dish was the dirtiest. During our experiment, we had some specific expectations that we needed to analyze.  Additionally, we needed to identify the dish that had the highest level of bacteria growth, to determine which one was the dirtiest.

In the end, we concluded our hypothesis was inaccurate. Earlier in our hypothesis, we stated, “Shaking your hands dry is the cleanest method of drying your hands.” After our experiment, we can quite clearly see that the cleanest petri dish is “hands dried with hand dryer.” Even though we were wrong, these results aren’t completely useless. Now we can answer the original question, “What is the cleanest way to dry your hands?” The cleanest way to dry our hands is by using a hand dryer.

We believe our project's focus is something we should consider daily when washing our hands. In reality, we think of washing our hands as something essential for hygiene. But this couldn't be further from the truth. Why? This is where our project comes in place. In short, our project's focus is whether bacteria can spread while drying your hands. Some people ignore this as most think washing and drying your hands helps prevent the amount of bacteria on your hand. But our project says otherwise. We wanted to find out how to dry our hands in the cleanest way possible. After some thorough examination of our experiment, we did 3 times each method. We concluded that the hand dryer was the cleanest, tissue being the dirtiest and shaking hands dry alongside paper towels fell in between. On a scale of 1 to 10 (10 being the cleanest and 1 being the dirtiest), the hand dryer would be a 10, the tissue would be a 1 and both shaking hands dry and paper towels would fall at 5.

- We labeled our Petri dishes to ensure that we could keep track of how much we tested and what we tested because the consequences of not labeling could have led to confusion, and swapping and in general could have messed up the whole purpose of our experiment.

- We made sure to keep a consistent focus during our experiment. If we didn't, we could have messed up the making of the agar. This was bound to happen as we almost solidified our agar as a result of us being distracted.

https://www.health.harvard.edu/blog/the-bacterial-horror-of-the-hot-air-hand-dryer-2018051113823

https://medicine.yale.edu/micropath/research/bacteria/

https://medicine.yale.edu/bbs/tracks/microbiology/research-areas/bacteria/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7149789/#:~:text=Bacterial%20infections%20have%20a%20large,%2C%20food%2C%20or%20living%20vectors.

We would like to express our sincere appreciation to our science teacher, Ms. Kale, and assistant principal, Ms. Lizotte, for their invaluable guidance throughout our project. They presented this wonderful opportunity to us. We would like to extend this thankfulness to our parents, for showing us their unwavering support.