Proposal

APPENDIX D

Science Investigative Project

Project Proposal Form

Name:

Qiu Biqing ( 20     )

Sec 2/13

Topic of investigation  :

Type of hand cleaning agent that remove bacteria most efficiently

A	Observations made
	On television there are many advertisements about antibacterial hand soap that can kill 99.9% of bacteria. On the other hand there are people who use ointments made from natural substances as antiseptics. I want to find out the amount of bacteria removed by each type of cleaning agent and hence the antibacterial properties of the two unconventional hand cleaning agents.  I would also compare the amounts of bacteria removed by natural and commercial antiseptics to see if there can be a substitute for antibacterial soap in nature.
B	Research Question
	Which type of agent among lime juice, lemon juice, water, normal hand soap and antibacterial hand soap removes bacteria from the hand most efficiently?
C	Hypothesis statement
	The antibacterial hand soap will remove bacteria from the hand most efficiently while water will remove bacteria from the hand least efficiently.
D	A short summary of research done on the area of investigation
	All types of bacteria can be found on your hands depending on what you touch, including many types of pathogenic bacteria. Normal hand soap removes bacteria physically. The bacteria on the hands take refuge under the surface lipids layer of the skin. Water is not able to dissolve the lipids layer; however, soap emulsifies the oil by forming a ‘bridge’ between polar water molecules and non-polar oil molecules, allowing water to mix well with oil. The alkaline components in soap also help to break down the surface fats layer, which is slightly acidic. Therefore normal soap does not kill the bacteria but enables them to be flushed away from the hand when rinsed with water. Antibacterial hand soap, in addition to the emulsifying properties of normal soap, contains active antibacterial chemicals which kill bacteria and microbes. A common such chemical is triclosan. However, research shows that there is not much difference between amounts of bacteria removed by either kinds of soap – normal soap can remove 95% of the bacteria, while antibacterial soap can remove 97%. (exact source unclear). However other research shows antibacterial soap killing bacteria much more efficiently than normal soap. Citric acid is able to kill bacteria by destroying their cell membranes. Food scientists have also proven that product made from citric acids and grapefruit oil removes microbes from fruits during food manufacturing more effectively than chlorine dioxide, killing reportedly 99.9999% of bacteria. (The striking similarity with claims about antibacterial soap makes the experiment much more interesting.) Citric acid is found in high amounts in lime and lemon. Lemon juice contains 1.44g/oz and lime juice 1.38g/oz of citric acid respectively.
E	Bibliography (Please refer to RS Students’ Handbook in RS Folder on Inet regarding APA Style Format)
	Wikipedia, (18 May 2011). Antibacterial soap. Wikipedia. Retrieved May 24, 2011, from http://en.wikipedia.org/wiki/Antibacterial_soap WikiAnswers, (unknown). How does soap work to clean things? WikiAnswers.  Retrieved May 24, 2011, from http://wiki.answers.com/Q/How_does_soap_work_to_clean_things UAB Medicine, (18 February 2008). Hand washing. UAB Health System. Retrieved May 24, 2011, from http://www.health.uab.edu/17728/ Renee Miller, (unknown). About the bacteria on your hands. eHow. Retrieved May 24, 2011, from http://www.ehow.com/about_4571973_bacteria-hands.html WikiAnswers, (unknown). What is in lemon juice that kills bacteria? WikiAnswers. Retrieved May 24, 2011, from http://wiki.answers.com/Q/What_is_in_lemon_juice_that_kills_bacteria University of Idaho (2008, June 26). Food Scientists Confirm Commercial Product Effectively Kills Bacteria In Vegetable Washwater. ScienceDaily. Retrieved May 24, 2011, from http://www.sciencedaily.com­/releases/2008/06/080625122930.htm Kristina L, Penniston M. D. and others, (March 2008). Quantitative Assessment of Citric Acid in Lemon Juice, Lime Juice, and Commercially-Available Fruit Juice Products. Pubmed Central. Retrieved 24 May 2011, from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2637791/