Science Buddies: "Ask an Expert"

I would like to do a research on the death rate of bacteria after use of hand sanitalizer. However, when I asked my science research teacher if I could do this research, he said it might be hard to count the number of bacteria. Is there any way to count bacteria right after the use of hand sanitalizer?
Thank you.

Hi,

Yes, you would do an experiment like this one: https://www.sciencebuddies.org/science- ... 3&from=TSW where you swabbed your hands before and after using hand sanitizer. It wouldn't be a perfect solution, but you could certainly compare the relative amount of bacteria before and after using hand sanitizer.

Sounds completely cool!

If you were to actually count the number of bacteria that may involve some complications such as involving dilution plating (a LOT of materials required) all the way to measuring OD of the bacteria...)

I suggest that if its a simple experiment you want to test out so far, you can always use qualitative observations of how bacteria grows in various amounts. For example, if petri dish A has hand sanitizer and petri dish B has ordinary soap, you can grow bacteria under those conditions (with a constant amount to start with) and then observe which plate seems to have the most bacteria after 36 h or so (this is again depending on the bacteria)

Anyways, I'd love to help with anything w/ microbiology because I've based a big science fair project on that

thank you for answering my question