Drop It and Swab It - The Truth Behind the Five Second Rule

We are discovering the truth behind the five second rule by swabbing food that has dropped on the floor and growing it in a petri dish.
Max Wong Oliver Lee
Grade 5

Presentation

No video provided

Hypothesis

We think that the five-second rule is false because we know that bacteria is everywhere and on everything and Max thinks he got sick from eating something off the floor at a restaurant once. We have learned that the most common bacteria (Staphylococcus according to North Mast Service). can travel a whole quarter of an mm in a whole five-second rule but we don’t know if this site is reliable and since the bacteria is not visible we don’t know where the bacteria is so we can’t tell if we are dropping the bacteria right on top of the bacteria or further away. 

 

Research

We did a quick google search and found  that most bacteria can travel at about a quarter of a mm in 5 whole seconds the most common bacteria on the floor according to google are Bacillus, Micrococcus, Pseudomonas, and Staphylococcus and the only one that remotely dangerous is Staphylococcus which can cause infection and blood clots and in a rare case pneumonia. Cancer is another symptom of Staphylococcus but in very rare cases.

The build of Bacteria has 9 main parts, Pilus (for attaching onto less grippy surfaces),Capsule almost like a shield cloak (for protecting the inner part of the bacteria from toxic sprays or liquid),Cell wall (A rigid external layer designed to provide structural support to the cell ),Plasma membrane(each cell has a protective shield called the plasma membrane),Ribosomes(responsible for making proteins),Nucleoid(the DNA of the bacteria),Plasmid(to give the bacteria genetic advantages such as antibiotic resistance ),Cytoplasm(The cytoplasm is a platform for other cells to land onto to repopulate/make more or new bacteria so that it can infect you're body 

 

Variables

Controlled variable  

The place where we drop the food 

Sterilized cotton swabs 

Sterilizing cotton swabs with hot water

Rubbing the cotton swabs on the petri dish RIGHT AFTER IT DROPS

Washing our hands after every experiment

 

Manipulated Variable

The timeframes the food was on the floor

1 second

5 second

1 minute

 

Responding variable

Amount of bacteria growth

Procedure

  • Get together to start planning you're experiment then get your materials like Hot water, Qu tips, Petri dishes, and a plastic Tupperware 
  •  take your desired food and use a stopwatch to time how long the food has been on the floor 
  • after it being on the floor quickly swab your food with you're sterilized qu tips (to sterilize them just put them into hot water and leave them in the hot water for 5-10 seconds) 
  • with the bacteria on the qu tip gently rub the qu tip on the petri dish and repeat as many times as desirable 
  • IMPORTANT label you're petri dishes and seal them with tape.
  • To seal the Petri dishes store them upside down in a plastic Tupperware in a warm-hot environment for about 1 week
  •  record data daily then on the last or 7th day count mold and colonies by counting the white and fuzzy things (mold) and the white-yellow specs (bacteria)

Observations

Apple 1 second 24                                                               

Apple 5 second 12

Apple 10 second 16

Grape 1 second 5

Grape 5 second 5

Grape 1 minute 9

Fingerprints 124

Control 0

Average Colonie Per Petri Dish 22.4444

Between now and the CYSF we are going to change some stuff.

Analysis

We did a quick google search and found  that most bacteria can travel at about a quarter of a mm in 5 whole seconds the most common bacteria on the floor according to google are Bacillus, Micrococcus, Pseudomonas, and Staphylococcus and the only one that remotely dangerous is Staphylococcus which can cause infection and blood clots and in a rare case pneumonia. Cancer is another symptom of Staphylococcus but in very rare cases.

The build of Bacteria has 9 main parts, Pilus (for attaching onto less grippy surfaces),Capsule almost like a shield cloak (for protecting the inner part of the bacteria from toxic sprays or liquid),Cell wall (A rigid external layer designed to provide structural support to the cell ),Plasma membrane(each cell has a protective shield called the plasma membrane),Ribosomes(responsible for making proteins),Nucleoid(the DNA of the bacteria),Plasmid(to give the bacteria genetic advantages such as antibiotic resistance ),Cytoplasm(The cytoplasm is a platform for other cells to land onto to repopulate/make more or new bacteria so that it can infect you're body

Observing bacteria | Bacteria | Microbiology Society

 

 

Conclusion

What happened? There were a lot of bacteria visible to the human eye there was a lot of colonies but with a quick count and a quick Google search we can find that 120-150 specs of bacteria are dangerous except only two of our experiments had 120+ specs of bacteria 

Why do you think it happened? The bacteria growth was suspected but at first, the sight was kinda disgusting the one thing we learned is that the mold is honestly more dangerous than the most common bacteria on the floor so anything with mold 1 or 100,000,000 mold is almost evenly sickening and dangerous.

But we believe that the reason the bacteria on 1s, 5s, and 1 min grapes were so similar even though they all have very different time frames was due to the grapes being so small they might not have picked up the bacteria. Unfortunately, we can not prove this theory true or false due to the lack of Petri dishes until further research and experimenting we cannot prove or refute this theory. 

What have we learned? Disgusting and a little terrifying but honestly it's not that dangerous but by with comparison with 1 second and control I honestly would have thrown it out but one thing I recommend is that you WASH YOUR HANDS cause the Fingerprints were absolutely DISGUSTING although we threw it into the garbage it was enclosed and with an elastic band so we think that the fingerprints and garbage were really the only fingerprints and we did fingerprints last so are fingers and already touched everything else. Make sure you wash your hands well.

 

Application

The next part of our experiment that other people can build on is to do different places like restaurants, public bathrooms, and even outside. This experiment (if continued further) will show how clean or dirty a place is and the likelihood that you might get sick. 

We have discovered a lot during this science fair project such as

1-The working and identification of bacteria and how they can be used against us and to use the helpful and non-harmful bacteria to our advantage also to wash your hands with soap to prevent harmful bacteria from getting into your body and negatively affecting your body!

 

 

Sources Of Error

We definitely should have tried a lot of different types of food for every item and also we should have tried drier or saltier foods.Trying diffrent places like a resturant or a public bathroom or even outside to know how dirty or potianly dangerous places where you could eat food off the floor from.

 

Citations

Cysf.org

Northmastservice.com

Hypertextbook.com

Youtube How to use Petri Dishes

Acknowledgement

Cysf.org

Northmastservice.com

Hypertextbook.com

Youtube How to use Petri Dishes

Adrienne Hui, Desree Yow, ollies uncle Willson (not his actual uncle )

ms saunders 




 

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