Do antibacterial hand soaps really work?

On average it takes 6 seconds for a person to wash their hands. Is this really long enough for the antibacterial agent in the hand soap to kill germs on the rsurface of the skin? You will need the following.

- normal hand soap
- antibacterial hand soap
- 4 agar plates

Students must develop their own experimental procedure.

1) Form a hypothesis.

2) Outline a detailed step by step procedure.

3) Collect data and presented in an appropriate format.

4) Reach a conclusion.

 

Use the hand soaps as directed on the labelling
Wash and dry hands as you normally do using paper toweling.
Label the agar plates, seal with tape and incubate.

Previously a student conducted the experiment to see if antibacterial hand soaps really worked.

Using 4 agar plates he touched his left thumb on one sterile agar plate ( plate 1) before washing and the right thumb on a second sterile agar plate (plate 2), again before washing.

He then washed his right hand with normal hand soap and wiped his hand dry using the paper hand towel. He then touched his right thumb onto a sterile agar plate (plate 3).

Next he washed his left hand with antibacterial hand soap and wiped his hand dry using the paper hand towel. He then touched his left thumb onto a sterile agar plate (plate 4).
Click for a more detailed image Plate 1, Plate 2, Plate 3, Plate 4  
1) Looking at the results, what hypothesis is supported by these results?
2) What were the dependent and independent variables in the students experiment?
3) View the video shown in this article and try to offer an explanation for the results.
4) What is the danger of over use of antibacterial soaps?
5) From these results, can we be confident that the antibiotic hand wash is not really effective against bacteria? Explain
6) How can the experimental procedure be improved?
Solution

A student conducted an investigation to see if there is an optimum time that the hand soap should stay on the skin, before been washed off, for maximum impact. Click to see the results.
Write a procedure for this investigation.
What are the dependent and independent variables.
What do the results suggest?