My hypothisis is that the most favourite slurpee flavour will have the dirtiest handle, because the handle of the favourite slurpee flavour would have been touched more than the other handles. The more people who have touched the handle the more germs that will be on the handle.

Background Research 

How long does it take for bacteria to grow?

• As little as 24 hours 
• In perfect conditions one bacteria can turn into 1 billion bacteria in 10 hours.

How does bacteria grow?

• Swipe the surface with sterile swabs and then transfer germs into agar dish when using a back and forth swiping motion over the whole  dish.
• Store in warm and dark place 

How do I dispose of materials at the end of the experiment? 

• Seal in a plastic bag and dispose
• Put in large zip lock bag with a few drops of bleach and put in trash

Controlled Variables

• Sterile swabs.
• Petri dishes with pre-poured agar.
• Conditions that the samples are stored in.
• Pressure you swab with.
• How many swabs you do.
• Same swabbing technique to deposit onto agar in petri dishes. 
• All samples taken on the same day, same time and same place
• Standard survey question delivered in same order.

Manipulated Variables

• Handle of slurpee flavour that was swabbed.
•  Surveying a variety of people about their favourite slurpee flavour

Responding Variables

• Bacteria growth (amount that grows).
• Different types of microorganisms.
• Number of votes for each flavour.  

Procedure

1. Call 7-eleven to get approval for your experiment.
2. Make a list of all the materials you will need for your experiment and gather them up.
3. Travel to a 7-eleven to collect your samples. 
4.  Confirm with the manager once you arrive.
5.  Using a sharpie, write 1 slurpee flavour on each of the 8 petri dishes .
6. Put on gloves.
7. Remove the lid of the first petri dish.
8. Take 1 sterile swab and wet it with distilled water. Rub it back and forth on the surface of the first slurpee flavour handle while twirling it to ensure that the whole sterile swab is covered.
9. Swipe the germ covered swab back and forth top to bottom across the agar in the petri dish while rolling the swab.
10. Rotate the petri dish 90 degrees and repeat step 9.
11. Dispose of the used swab in the garbage. 
12. Put the lid on the petri dish and wrap tape around the edge to seal it.
13. Repeat steps 7-12 for each of the slurpee flavours.
14. Disinfect all the slurpee flavour handles used in the experiment with a Lysol disinfectant wipe and dispose of gloves in the garbage can.
15. Store samples in a warm safe place. 
16. Take day zero photo.
17. Each day take a photo and record observations. 
18. Create a survey on the computer asking people their favourite slurpee flavour from the list of flavours used in the experiment.
19. Compare results of survey to petri dish results.

Removing sterile swab from the packaging. (Note: Should have been wearing gloves).

Rubbing the sterile swabs back and forth on the surface of the slurpee flavour handles while twirling it to ensure that the whole sterile swab is covered. 

Swipe the germ covered swab back and forth top to bottom across the agar in the petri dish while rolling the swab. Rotate the petri dish 90 degrees and repeat what you just did.

Take Day 0 photo of the petri dishes.

Observations 

Germ Progress Photos	What I Observed
	Day 0 Jan. 22, 2024 First Day Photo. Nothing to observe yet.

Final Project Results

Final Germ Growth Results:

Conclusion          

My hypothesis is that the most favourite slurpee flavour will have the dirtiest slurpee machine handle. I think this because more people will touch the handle that is the favourite flavour. If more people touch it then there will be more bacteria on it.

Unfortunately my results did not support my hypothesis. 

The most liked slurpee flavour was Dr. Pepper and its petri dish didn't appear to grow any visible germs. When I took my samples it went good, however maybe when I took my samples I didn't swab the Dr. Pepper handle as well as the other handles. I am unsure when the handles were last cleaned and how many customers had come since. It was also a week day with cold weather so not many people may have touched the machines. The area around the store was quite empty so it’s likely  that not many people went into the store.   

If I did this experiment again I would start earlier so I had time to do at least two trials not just one.  I would also ask people their top 2 favourite flavours because people don’t usually get only one flavour in their slurpee.

The project is important because it proves that the handles at 7-11 are dirty. It warns people that they should their hands after touching the slurpee machine handles. If they don't wash their hands they could get sick from the germs.

Sources of Error

• Forgot to wear gloves
• Didn't ask when the slurpee handles were last cleaned
• Didn't store petrie dishes in the most warm place in my house. Should have stored in a cupboard next to my dishwasher.
• Count how many times you swabbed each handle and use this exact amount of times each time you swab.
• Asked only about their favourite but most people get more than one flavour when they buy a slurpee.  
• Give time for the germs to grow-7 days if possible.

Recommendations

• Give people the choice of their top 2 flavours that are their favourite because people usually get more than 1 flavour in their slurpee or use one flavour as a base e.g. Pepsi, Coke.
• Do experiment in warmer months when people are more likely to get a slurpee e.g. June, July, August.
• Don’t forget to put gloves on before swabbing the slurpee machine handles.
• Ask staff or manager when the slurpee machine handles were last cleaned and how many customers had used the slurpee machines since.
• Collect samples from a convenience store that gets lots of customers or is near a school.
• Remember to swab each handle the exact same amount of times and the same way.
• Set an alarm to ensure that photos of the petri dish samples are taken at the exact same time.
• Have people say their least favourite and most favourite. Asking their least favourite would give me information to compare to the petri dish that grew the least germs. 
• Take photos of petri dishes in an area that has good lighting.
• Hand drawn sketches with labels because scienctist often do labels and the pictures were hard to see.
• Store petri dishes in a warmer and darker place (better for growth).
• Find out which day of the week and time of day has the most customers coming to purchase slurpees normally and choose that day/time of the week to go collect samples.
• Do more background research 

Websites:

• Calgary Youth Science Fair 
  • https://www.cysf.org/
• Home Science Tools Resource Center
  • https://learning-center.homesciencetools.com/
• Steve Spangler Amazing Science Experiences
  • https://stevespangler.com/experiments/growing-bacteria/
• Science Buddies
  • https://www.sciencebuddies.org/science-fair-projects/science-fair

Thank you to my mom because she helped me throughout this project and guided me when I needed help. She also helped me to keep a positive mindset when my work got difficult.

Thank you to my dad because he tried to help me even when I got frustrated he still tried to help me.

Thank you to my sister Ivy for helping take photos when I collected my samples.

Thank you to the following teachers who answered my questions and helped me: Ms. McGrath & Ms. Swinton at Hawkwood School and Ms. Blyth at Simons Valley School.

Thank you to 7-11 for allowing me to collect microorganism samples.