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Bacteria and disinfectants. Hypothesis. Research Question: Which products work best to disinfect my kitchen table? Hypothesis: If I use vinegar and water on a table then there will be fewer bacteria on the table than if disinfecting wipes or spray was used.
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Hypothesis • Research Question: Which products work best to disinfect my kitchen table? • Hypothesis: If I use vinegar and water on a table then there will be fewer bacteria on the table than if disinfecting wipes or spray was used. • Problem statement: Bacteria can cause infections and diseases.
Abstract Bacteria can be a problem. It can cause infections and viruses. In order to get rid of bacteria, a disinfectant needs to be used. This experiment will find which disinfecting product works the best, disinfecting spray, disinfecting wipes, or water and vinegar. The procedure was to first use a cleaning product on a table then take a Q-tip, dip it in distilled water and swab the spot that was cleaned. The Q-tip was placed in a test tube with a nutrient broth, left to sit for 5 min, then, the broth was poured onto Petri dishes with a nutrient auger on it. Then the Petri dishes were put into an incubator for 2 days. After the 2 days were up the Petri dishes were removed from the incubator and the number of colonies that grew were counted and recorded. The disinfecting spray worked that best and it killed all of the bacteria, and the disinfecting wipe only worked slightly better than the water and vinegar solution.
Variables • Control- the control is how many bacteria are on the table without using any cleaning products. • Manipulated variable- the manipulated variable is the different disinfecting products. • Responding variable _ the responding variable is the number of bacteria colonies that grow on the Petri dishes. • Constants- the constant variables are the table, the Q-tips, the temperature of the incubator, the time that the Petri dishes are in the incubator, the nutrient broth, the and the ratio of vinegar to water.
Materials • Disinfecting spray • Disinfecting wipes • Distilled water • Tap water • A table or counter top • Paper towels • Q-tips • Petri dishes with nutrient auger • Test tubes with nutrient broth
Procedure • Before using any cleaning products on the table, dip a Q-tip in distilled water and swab the table. Do this a total of 4 times. This will be the control. • Put the Q-tips used to swab the table in separate airtight bags so they do not get contaminated by the bacteria in the air. • Spray disinfecting spray on the table and wipe it with paper towels. Wait for it to dry. Dip a Q-tip in distilled water and swab the area that was disinfected with the spray. Do this 4 times making sure to put each Q-tip in a separate airtight bag. • Wipe an area of the table with a disinfecting wipe. Make sure the area that is wiped was not sprayed with the disinfecting spray. Wait for it to dry. Dip a Q-tip in distilled water and swab the area that was disinfected with the spray. Do this 4 times making sure to put each Q-tip in a separate airtight bag. • Make a solution of equal parts vinegar and water. Dip a paper towel into the solution and wipe the table. Make sure the area that is wiped was not the same area that was sprayed with the disinfecting spray or wiped with the disinfecting wipe. Wait for it to dry. Dip a Q-tip in distilled water and swab the area that was disinfected with the spray. Do this 4 times making sure to put each Q-tip in a separate airtight bag. • Put all of the Q-tips in a test tube with a nutrient broth in it. Label each tube. • Wait 5 minutes and pour the broth onto labeled Petri dishes. Make sure the broth gets spread over the whole plate. Do not put the Q-tip on the dish. • After putting the broth on all of the Petri dishes put them into an incubator at 30 degrees Celsius for 2 days • After 2 days check on the Petri dishes and count the number of bacteria colonies that have grown. Put the dishes back in the incubator. Record the data on the data table. • Check the Petri dishes again on the third day and count the number of colonies. Record the data.
Review of literature • Even though most bacteria are harmless pathogenic bacteria can cause sickness and disease.(Kaplan, N.D.) • Most household surfaces are able to grow bacteria. (how can you kill bacteria, 2009) • A disinfectant removes infection and disease causing organisms. (UCMP, N.D.) • Sterilization is the removal of bacteria using high heat. (Parr, N.D.)
Day 1 * There was one big bacteria colony Day 2 ** The big colony grew and a second colony developed
Conclusion • The spray worked the best and killed all of the bacteria, so my hypothesis was not supported. • The vinegar and water worked almost as well as the disinfecting wipe. • It is more cost effective and less harmful to the environment to us vinegar and water then it is to use a disinfecting wipe.
Bibliography • "Cleaning, Disinfecting and Sterilizing (Reptiles)." Melissa Kaplan's Herp and Green Iguana Information Collection. Web. 27 Oct. 2009. http://www.anapsid.org/cleaning.html • "How can I Kill Bacteria?" WiseGEEK: clear answers for common questions. Web. 27 Oct. 2009. <http://www.wisegeek.com/how-can-i-kill-bacteria.htm>. • "How to Kill Bacteria | eHow.com." EHow | How To Do Just About Everything! | How To Videos & Articles. Web. 27 Oct. 2009. • <http://www.ehow.com/how_4505722_kill-bacteria.html>. • "Life History and Ecology of Bacteria." UCMP - University of California Museum of Paleontology. Web. 27 Oct. 2009. • <http://www.ucmp.berkeley.edu/bacteria/bacterialh.html>.
