How to Find Out Whether Non-Bacterial Soap Works Better Than Antibacterial
Bacteria science is one area that captures the interest of most children. Students can do a lab project with bacteria that shows them the difference between antibacterial and regular soaps by observing the bacteria after washing with each type of soap. The results may surprise both you and your students.
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Things You'll Need
- 3 petri dishes per child
- Agar solution
- Raw chicken
- Regular bar soap
- Antibacterial bar soap
- Sterile swabs
- Sticker labels
Instructions
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Melt the agar solution by placing the bottle in a hot water bath for 5 to 10 minutes.
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Fill each petri dish 1/4 full of agar solution. The solution will set up as it cools.
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Have the students rub their hands on raw chicken to pick up some bacteria.
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Have each child swab his or her hand with a sterile swab and then gently rub the swab over the agar solution in the first petri dish. Ask each child to place the lid on that petri dish and then add a sticker with the words "No Soap" and his or her name.
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Ask the students to wash their hands with regular bar soap. Encourage them to wash for the proper amount of time by having the class sing "Twinkle Twinkle Little Star" while they are washing. They are not allowed to finish washing until the song ends.
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Have each child swab his or her hand with a sterile swab and then gently rub the swab over the agar solution in the second petri dish. Ask each to place the lid on the petri dish and affix a label with the words "Bar Soap" and his or her name.
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Have the students rub their hands on the raw chicken again to pick up more bacteria.
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Ask the children to repeat the hand washing procedure--this time with antibacterial soap.
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Repeat the swabbing process and label the third petri dishes "Antibacterial Soap" and each child's name.
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Collect the petri dishes and place them in a dark closet at room temperature for 1 week.
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Pull out the dishes and hand them back to the students. Ask the students to discuss their observations. With this experiment, there will be the same amount of bacteria growing in both soap dishes but a higher amount of growth in the dish that was swabbed before the students washed their hands.
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Explain to the students that the reason that the growth is the same is because there are different kinds of bacteria, and antibacterial soap does not kill all bacteria types. The lesson and conclusion is that both soaps work well at reducing bacteria.
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Tips & Warnings
Anti-bacterial soap is more effective than regular soap at killing bacteria such as E coli and salmonella and is especially useful after handling animals.
References
- Photo Credit Jupiterimages/Comstock/Getty Images
