At the Discover STEM event at La Roche the other week we simulated the spread of an EPIDEMIC via a group of people to spread a disease through hand shaking.  Use the information below to trace the spread by making a KEY/chart that leads us to Patient Zero.

Final submissions to enter to win a telescope came in the night of Oct 30th, 2018 and that contest has now ended. You can still try your luck at tracking the spread for fun though and click the button below to see the Winning KEY of the map of the spread we received this year. Thanks to all those who attempted and science on!

We Incubated petri dishes for 48-72 hrs so the bacteria would grow colonies big enough to see with the naked eye (they look like Magenta/Reddish/Pink dots).  See photo results of each plate to make your key to determine the spread of the "disease" through people's handshakes.

What AM I trying to determine from the results?  

A: Who is patient zero (or candidates for patient zero), how did the bacteria (disease) spread, and who are the lucky ones?  Use whatever resources you want.  Make your own flow chart/key of the spread and then click GET THE RESULTS button below (which we add after this simulation contest is over) to compare and see if you solved the puzzle correctly!



We handed out a bunch of gloves coated in a bacterial growth broth medium (bacteria food in liquid form).  All of the gloves were coated with broth so that no one would be able to tell if they had the glove that had the "infectious disease"(i.e. PATIENT ZERO) or not…only one individual actually received a glove that had broth contaminated with live bacteria. Everyone was to shake hands with two and ONLY two other people and record the numbers of who they shook with.

Therefore, when Patient Zero (the person who had the disease first) swabbed their plate from their own glove their results should show the highest # of bacteria (or highest # of bacterial colonies: Each pink dot on the plate is one colony) on their petri dish.  If the plate has an extremely high amount of the bacteria you may not see individual "dots" or "colonies" but will simply see a streak/lines which is so many that it just forms together in what we call a "lawn" of growth.  This is someone who was either patient zero or infected with a heavy amount at the beginning of the experiment.

Some people will have shaken with that person and then shaken with someone else, spreading the disease.  Some may have been "lucky" and shaken with two people before the spread and may not have gotten infected.  The less bacterial "colonies" a person has on their plate, the further removed they were from contact with Patient Zero. 

*This bacteria grows pink/magenta so only pink colonies are counted (as other colonies could just be contaminants from other things that were on the gloves).  You DO NOT have to actually count all of the dots if you can visually tell that there are less than another plate combined with the knowledge of handshake order to determine the spread.

*Keep in mind that although people were only supposed to shake two hands, human error occurs. If something seems out of place, try to account for human error and move past it to make your KEY/CHART of the spread. Keep in mind it is also possible for someone that did not have growth on their plate to also spread it to others. Their swab technique could have been faulty, allowing them to avoid picking up the bacteria from their glove and transferring it to their plate. Keep this type of thing in mind when creating your chart! Good luck everyone!

THE Result Plates from the DISCOVER STEM “SIMULATION OF AN EPIDEMIC” Workshop are in the photo gallery directly below:

Photo Results from Spring 2018 EPIDEMIC SIMULATION are directly below: If you want to practice with this and see the result key to make sure you’ve got the idea feel free Check these out first!


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