Eww, gross!

which commanly used item/suface in the class (or school) is the dirtiest
Léa Bourdon
Grade 6

Hypothesis

If I test which item or surface is the dirtiest then I think the front door handles will be the dirtiest because every morning they get used by teachers/staff, grade six students, late students, visitors, little leaders etc. Even though the front door handles and the stairway railings get sprayed everyday monday to friday I still think once the spray cleans it more germs come along after.

 

Research

People touch their eyes, nose, and mouth without washing their hands way more than they realize.Those little nasty germs are everywhere and take trips with you without you even knowing. 

Some of the diseases you can catch by not washing your hands are Coronavirus (Covid-19), the Norovirus (stomach bug), the common flu, Conjunctivitis (Pink Eye), Salmonella (food poisoning), Respiratory Syncytial Virus (RSV), Streptococcus (Strep Throat) and there are many more. You can minimize the spread of many of these germs by simply washing your hands regularly using soap and water for at least 20 seconds.

Currently, most hospitals in Canada are experiencing extremely long wait times and overcrowding due to the various strains of some of these preventable diseases. To help reduce the number of sick people in hospitals, people are encouraged to wash hands regularly, stay home when they do not feel well, and get vaccinated. 

What is Bacteria?

Bacteria are microscopic living organisms that only have one cell. There are millions of different types of bacteria that can be found in your body and are beneficial to you. Other bacteria can make you sick. But thanks to health care providers, they can treat many bad bacterial infections with antibiotics.

Is bacteria a bad thing?

Some bacteria are actually good for you but not all of them. Some of them can make you really sick or sometimes even kill you. The good ones make up your microbiome, which keeps your body healthy by fighting the bad ones off. 

How does bacteria spread?

Bacteria can spread through air, water, food or living vectors. It can also spread with contact when you touch someone, or when you touch a commonly used object such as a pen at a hospital for example. Oftentimes these objects are not regularly disinfected therefore spreading bacteria from one person to the next.

How does sanitizer kill bacteria?

The abrasive and alkaline nature of soap plus the heat of hot water kills the bacteria. As long as the sanitizer you use is 60% alcohol based, it will do the job. But sanitizer can only kill bacteria with soft “shells” because the alcohol in it isn’t very strong and can only do so much.

Does sanitizer kill covid 19?

Yes, sanitizer kills Covid 19 germs and bacteria. Covid 19 bacteria doesn’t have a thick and strong wall to protect it, so the sanitizer can kill it.

Why is the spread more intense during winter?

The spread is more intense because the cold air itself damages the immune response occurring in the nose. The cold air kills all the good bacteria fighting the bad bacteria. You then get sick because there's a whole bunch of bad bacteria in your nose and some of the bad bacteria may start spreading.

Diseases you can catch when you do not wash hands

  • Coronavirus (Covid 19) 
  • Norovirus (the stomach bug) 
  • the common flu
  • Respiratory Syncytial Virus (RVS)
  • conjunctivitis (pink eye) 
  • Hepatitis A
  • Salmonella (food poisoning)
  • Mononucleosis
  • Coxsackievirus (hand, foot, and mouth disease) 
  • Escherichia coli (E. coli)
  • Group A Streptococcus (Strep throat)
  • Staphylococcal Infections (Staph)

 

Variables

Independent Variable

An independent variable is the one thing you change in your experiment and the rest has to stay the same. For example, if I test which item is the dirtiest and I test the school’s front door handles, the railings on the staircase in the center of the school, and My teacher’s desk, then my  independent variable is the different surfaces.

Controlled Variable

A controlled variable is everything that does not change. For example, the containers I used to hold the germs, the gelatin and all the germs stayed in a drawer for 3 days in the same type of lighting.

Dependent Variable

The dependent variable is the variable you measure. For example, in this experiment I am measuring which surface is the dirtiest in the school depending on the germs that have grown in the petri dishes.

Procedure

I decided to test three surfaces and test them three times each and let each of them sit for seven days. I put them into three groups of three and labeled each group one of the surfaces. I then put hot water in one set of petri dishes from each group and mixed it in with agar powder on the first day of testing. Next, I took a q-tip and swabbed the surface with the q-tip and then gently swabbed the petri dish with agar powder. I observed the three dishes for the next seven days and on the seventh day, I repeated the exact procedure for the second group of testing. And of course on the seventh day of that second group of testing, I swabbed the last group. On the seventh day of every group, I observed and looked at each set of samples to see which surface might be the dirtiest.

Observations

                                                                                                                        

                                                             

                                                    

Analysis

              

          

Conclusion

In conclusion, my teacher's desk (trial 2) was the dirtiest with 1,032 but there was also a sub that day when I swabbed so most kids in my class stayed at their desks. That means the sub clearly does not wash her hands often. She also has a daughter and they hang out in the classroom for a little while after school hours. The sub’s daughter was also little so she probably doesn’t wash her hands much either. So that could have led to growing more bacteria. My teacher also sprays her desk everyday after school but on the one day she wasn’t there it didn’t get sprayed therefore leading to more bacteria. The other trials on my teacher’s desk had way less bacteria. For example trial 1 only had 67 and trial 3 had 120. The next dirtiest was the front door of the school in trial 2. The difference between the  2 other trials isn’t as significant as my teacher’s desk was. Trial 2 of the front door had 213, trial 1 had 109 and trial 3 had 120. Of course last but not least the stairway railings, trial 1 had 63, trial 2 had 86 and trial 3 had 196 spots of bacteria. So that means after 7 days my teacher’s desk was the dirtiest. Therefore my hypothesis was incorrect.       

 

 

Application

In 2019 (covid year) there were a lot of care-taking staff and they're job was to clean all the door handels. But now after covid most of the care taking staff left and now it's only a couple janitors and Mr.Jonathan our head janitor. Also during covid teachers, staff and students were encouraged to wash they're hands and spray they're desks before and after eating. We also had spray our desks at the start and end of the day. Now we are encouraged to only spray our desks at the end of the day and they're not super strict with washing our hands before eating.

Sources Of Error

1. Transferring petri dishes from school to my house

2. Different humidity levels and temperature inside the school versus at home

3. Taking the petri dishes out of the drawer at different times

4. Using dry q-tips

5. Agar powder didn’t let bacteria grow

6. Changing the environment throughout the experiment

7. Opening the petri dishes to observe but therefore exposing it to air

8.Yes, my bacteria did not grow as I suspected it would. I believe the reason that it did not grow was because it did not have enough heat or moisture. I also think it did not have enough time to sit in a proper environment. In the past, students who have tested bacteria in the school using the agar powder claim that it took them closer to 2 weeks for them to see any bacteria. I will continue to watch the petri dishes for another week to see if any bacteria will grow. The agar powder may have also been faulty meaning it may have gone stale before I got it. In my opinion, I believe that it was more likely that I did not give it enough heat or put it in the right place. If I decide to do this experiment again, I probably will not put the petri dishes in a drawer. Rather, I would put them near a heat source so that they would get constant heat 24 hours a day for a 2 week period. In conclusion, my experiment failed because I did not get the results that I was hoping for, therefore, I do not have any corresponding data for my graphs.

 

Acknowledgement

I want to thank my teacher Mme Boussaha for helping me with all my testing, giving me supplies, cutting all my titles on her cricut and helping me calm down when I got really stressed. I would also like to thank my mom & dad for helping me with my trifold, keeping me on task and supporting me. And a thanks to Mrs. Van Den Eynden for reasurance and guidence. Also a big thanks to my little brother for reasuring me on our school science fair day if it weren't for him I don't know what would have happened but it wouldn't have been good. I wouldn't have been selected to go to CYSF without those people and wouldn't be nearly as calm as I am now. So thank you so much!