Which Item Has More Germs

We recently participated in a local science festival for 4^th-6^th graders, where we shared a few experiments using our pH and sanitizer test strips, as well as our dipslides. We decided to do a little experiment with the dipslides testing some items around the office to see which had the most microbes. The results were interesting, and the students had fun with it, so we decided it was worthwhile sharing on the blog.

We used a Nutrient-TTC / Rose Bengal dipslide to test a cell phone, the men’s bathroom toilet, and the push button on the breakroom microwave. We asked all of the students to guess what item had the most germs. About half of them guessed the toilet, while the other half guessed the cell phone. Only a handful of students guessed the microwave button.

So, what do you think?

Surprisingly, here were our results:

The cell phone:

The microwave button:

The toilet:

We concluded our microwave push button was the dirtiest! The cell phone was next, followed by the toilet. Our 4^th, 5^th and 6^th graders were intelligent in their conclusions as to why we got these results.

Many of them stated that the toilet gets cleaned more often than the cell phone or the microwave. We expect the toilet to be dirty and full of germs, so we clean it often. The microwave is used by everyone in the office, and is not only touched by hands, but also by food. It (obviously) doesn’t get cleaned as often because we don’t think about it like we do the toilet. The cell phone gets touched a lot, but usually only by one person’s hand, not multiple people.

All correct answers! So, what did we learn? Clean the microwave!

Try testing some items around your house or office that you think might be full of microbes to see what results you get. It can be fun and very informative!