Ew Gross! Finding Germs in Your Kitchen

Research Questions:

• What types of bacteria are there?
• How does bacteria grow?
• What is the composition of a bacteria?
• How does bacteria transfer?
• What can be done to prevent bacterial illnesses and contamination?

Materials:

• Potatoes
• Veggie Peeler/ Knife
• Plastic baggies with labels
• Gloves (sterile)
• A widely-used surface
• A dark room
• Pen/paper
• Optional: 2-3 other people

Experimental Procedure:

1. Peel and slice potatoes with gloves on. It is best if they are cut into similarly sized portions.
2. Five pieces is ideal. (Only an adult should do this.) 
3. Prepare a control by placing a slice of potato in a plastic baggie. Label it “control” and set that aside. Gloves should be kept on until step 5.
4.  With one slice of potato, cough and blow on it for 1 minute. Place that slice in a plastic baggie, label it “mouth/oral contact” and set it aside.
5. With the third slice of the potato, rub it for 1 minute on a surface that is regularly used by people, like a table or a counter. Place in bag and label that “surface contact” and set it aside.
6. Take off gloves. With the fourth slice of potato, simply rub the potato with your hands, fingers, and between your palms. Place in bag and label that “Single human contact” and set it aside.
7. It is recommended that you do the optional portion of this experiment. To do this, take the last potato slice and rub it like you did in step 5. Pass the potato slice along to your helpers and have them do the same thing. After this is done, put it in a plastic baggie and label it “Multiple human contact.”
8. After all those steps have been completed, take all your bagged potato slices to a dark room.     
9. Leave them there for 5-7 days. Monitor day-by-day progress and record in the charts below.
10. After allowing them to sit in the dark room for 5-7 days, observe them and record results. 

MOUTH/ORAL CONTACT

SURFACE CONTACT

References:

• Brown JR, Doolittle WF (December 1997). "Archaea and the prokaryote-to-eukaryote transition". Microbiology and Molecular Biology Reviews 61 (4): 456–502. 
• Davison J (1999). "Genetic exchange between bacteria in the environment". Plasmid 42 (2): 73–91. 
• Porter JR (June 1976). "Antony van Leeuwenhoek: tercentenary of his discovery of bacteria". Bacteriological Reviews 40 (2): 260–9. PMID 786250. PMC 413956 
• Whitman WB, Coleman DC, Wiebe WJ (June 1998). "Prokaryotes: the unseen majority". Proceedings of the National Academy of Sciences of the United States of America 95 (12): 6578–83. 
• Zumft W (1 December 1997). "Cell biology and molecular basis of denitrification". Microbiol Mol Biol Rev 61 (4): 533–616. PMID 9409151 PMC 232623
• http://cellsalive.com/ 
• http://science.howstuffworks.com/bacteria-info.htm
• http://www.ucmp.berkeley.edu/bacteria/bacteria.html