SILVER

Where the most bacteria is in our school?

We are taking samples of six places in our school to find out where is the most bacteria in our school.
Ben Hallamore Keenan Mitchell
Grade 6

Hypothesis

Since the bathrooms at school are warm and humid areas, there is more exposure to bacteria. Warm and humid places are perfect conditions for the bacteria to grow.

Research

At the beginning of the school year there were a lot of kids getting sick. We started to think about all the bacteria lurking in our school.  We were thinking about all of the places that people touch and wondering if all of those areas in the school are cleaned? 

Variables

Controlled variable: Temperature, number of days that the bacteria grew, light

Manipulated variable: 6 places that were swabbed for bacteria

Responding variable: bacteria growth

Procedure

The materials that we used were: 

  • Sterilized Petri DIshes
  • Extra Long wooden cotton swabs
  • Nutrient Agar powder for growing the bacteria 

Using petri dishes, cotton swabs and agar, we tested 6 areas where we thought the most germs are in our school. To make sure we didn’t ruin our test samples, we used cotton swabs to collect the bacteria from each area in the school. 

The nutrient agar was placed in the petri dishes and the cotton swab was swiped on the six areas and then placed in the agar. The petri dishes were covered with lids then observed for potential bacteria growth. 

The six areas we chose were:

  • Piano keys in the music room
  • Toilet seat in the division two boys bathroom
  • Handle of a floor hockey stick
  • Button on the water fountain
  • Doorbell at the school entrance
  • EDC/Gr.2 Mrs. Part door handle 

Observations

We observed the bacteria for 10 days. The bacteria was exposed to daylight and the temperature was controlled to 20 degrees.  Each day we observed the bacteria to see how the samples changed. During the first three days the bacteria looked the same as it did on the first day. After four days we noticed the bacteria started to grow in the Doorbell, EDC door handle, piano keys, water fountain, floor hockey stick. On day 5 all of the petri dishes had bacteria growing in them but the doorbell was definitely the worst, it was super gross. Six days after collecting the samples, we could smell the bacteria and agar.  On the seventh day we noticed that the piano key and floor hockey stick bacteria was changing colors. On the eighth day the piano keys and the floor hockey stick samples had grown a lot. On the ninth day we could see mold in the toilet seat, piano key and floor hockey stick petri dishes. On day ten we threw out the petri dishes.  We had to place them in a Ziploc bag and seal it and then we put that Ziploc bag in another Ziploc bag and sealed it before throwing it in the garbage. 

We noticed that the different colors and shapes that formed. Some of the bacteria looked like moldy hairs, some of it was raised, some of it was shiny, a lot of the bacteria was a circular shape. The bacteria turned different colors like white, green, orange, brown, and yellow.

These are our observations of the petri dish.

Area Swabbed  Day 1  Day 2 Day 3 Day 4 Day 5 Day 6 Day 7 Day 8 Day 9 Day 10
Floor Hockey Stick Handle No Change No Change No Change white spots mold starting bigger mold lots of shiny white mold, changing color, yellow and green mold growing  huge mold, green and yellow In the garbage
School Doorbell No Change No Change No Change grey hairy white spots Growing looks like moldy hairs More moldy grey hair Even more moldy grey hairs big white formation happening most of the dish is full of bacteria In the garbage
Toilet Seat No Change No Change No Change No Change white spots white spots green mold starting bigger mold yellow and green mold In the garbage
Piano Keys No Change No Change No Change white spots mold , shiny white spot mold forming changing color grey and white spots yellow and green mold In the garbage
EDC Door Handle No Change No Change No Change white spots more white spots bigger white spot bigger white spots yellow shiny raised spots darker yellow spots In the garbage
Button on water fountain No Change No Change No Change white spots shiny white spots bigger white spot bigger white spot more white spots small yellow spots In the garbage

Analysis

https://drive.google.com/file/d/18LScbQCeOnFCTfc0U9z9exxy8bCobmW0/view?usp=sharing

We analyzed the photos separately and documented our findings.  When we talked about our analysis we noticed that we had the same analysis of which item had the most to least bacteria. 

Our Overall Analysis: 

  1. Doorbell 
  2. Floor hockey stick handle
  3. Piano keys
  4. Div 2 boys bathroom toilet seat 
  5. EDC/Gr.2 Mrs. Part door handle 
  6. Water fountain

Keenan's Analysis of the bacteria from most to least: 

  1. Doorbell 
  2. Floor hockey stick handle
  3. Piano keys
  4. Div 2 boys bathroom toilet seat 
  5. EDC/Gr.2 Mrs. Part door handle 
  6. Water fountain

Ben's Analysis of the bacteria from most to least: 

  1. Doorbell 
  2. Floor hockey stick handle
  3. Piano keys
  4. Div 2 boys bathroom toilet seat 
  5. EDC/Gr.2 Mrs. Part door handle 
  6. Water fountain

Conclusion

Based on our pictures of the experiment, the doorbell was the place that had the most bacteria. 

Why do we think the doorbell had the most bacteria?

Keenan: I think the doorbell has the most because it's outside and lots of people touch it each day. The people that touch it don't sanitize before they ring it and it's not cleaned after each person touches it. 

Ben: I think the doorbell has the most bacteria because with it being outside of the school anyone can touch it. People don't have to sanitize their hands before they touch the doorbell but if people are entering the school there is a sanitizing station as soon as they walk through the door.  I don't think that the doorbell is cleaned or sanitized  as often as the other areas that we swabbed. 


 

Application

This past year we have all been reminded that to stay safe we need to wash our hands regularly, and we need to wash them for at least 20 seconds. When we can't wash our hands we need to use sanitizer and we sanitize our hands nine to eleven times per day while in school.  We sanitize our hands as soon as we get in to school, before and after gym class, before and after music, and we wash our hands after using the washroom.  The water fountain is off limits this year so we aren't touching that.  

We are hopeful that all of this handwashing and sanitizing is stopping the spread of bacteria. We want to remind people to wash their hands, so that they stop spreading bacteria. 

Sources Of Error

We took the bacteria samples to Ben's house to grow.  We wanted to have an even temperature for the bacteria so we set up a heater in the area where we had the bacteria. The temperature was at 20 degrees and sometimes the heater turned off because we didn't notice that the heater was on a timer. This was a source of error because we weren't able to control the temperature the way we planned to. 

Citations

Plugfelder, Bob, Growing Bacteria for Science Fairs, sciencebob.com; 2019

Mould, Steven, What are Bacteria? The Bacteria Book: The Big World of Really Tiny Microbes; P. 17. DK Publishing, 2018, New York, NY

Leung, Beatrice, Genetech, Inc. Liu, Shijun, Science Buddies, Interpreting Plate,  sciencebuddies.org; 2021 

Parents - Christy Robertson, Melissa Mitchell-Moisson, Joel Hallamore, Steve Moisson 

Acknowledgement

We would like to acknowledge everyone who has worked so hard during this difficult time to keep our schools clean and sanitized so that everyone including our friends, teachers, and school staff are able to stay safe and healthy. 

Sincerely, Ben and Keenan