Science Buddies: "Ask an Expert"

My daughter is in the fourth grade and wants to test the germs on her hands. We would like to test both hands for germs, then wash with a bar of soap, rinsing one hand in warm water and one in cold to see if there is truly a difference in germ reduction when using cold or warm water to rinse.

So my question is this, what is the best way to test for germs. I have access to a low powered microscope (purchased a store like Wal-Mart) but am unsure what to do from there. Please Help.

Thank You So Much In Advance!!!

This site will give you some idea of how to test for microbial growth. It uses coins, but the process is the same

Testing the Dirtiness of CoinsTesting the Dirtiness of Coins. ... (http://www.science-projects.com.Sterilization.htm) ... Did you see signs of microbial growth around the coins? ...
http://www.science-projects.com/BBMicro-Coins.htm - 28k - Cached - Similar pages


For the hand washing project - you will be measuring differences in microbial growth. That would include "germs" as well as the natural microbes growing on everyone's skin.

You will need to work with the teacher or science teacher to do this type project.

Matt Mulanax

Dear Lorrie,

This is an interesting project!

To test for different amounts of bacteria, you may swab your daughter's hands and grow the "germs" on agar plates. For Science Buddies information on agar, check out this link: https://www.sciencebuddies.org/science- ... Agar.shtml

You may want to do the test more than once. If you do, it may be good to run the water over a thermometer to test the temperature for each trial. That way, we know what "cold" and "warm" mean on an absolute scale.

Good luck, and feel free to post back with further questions.

Cheers,
Heather