A week or so ago, we got started on a project that arose from Christmas. Santa had left Mr. D. some interesting things in his stocking, including kits containing petrie dishes, agar crystals, and fine-tipped forceps. What to do? What to do?
We set about collecting germs! Mr. D. has seen lots of video content about germs already so he knew some of the obvious places to try but first, like good scientists, we needed to prep.
The agar crystals (mixed with water and sugar) are poured into the petrie dishes and then left at least overnight, preferably in the fridge, to ‘set’. We left ours a week – well – other things came first during that week.
Then we used hot pink nail polish to mark “12 o’clock” on the lid – both of us anticipated that it would be hard to tell without a marker of some sort.
With a wet cotton swab for each sample, we swiped surfaces that we thought might have germs, then swiped the swabs against the agar. We made sure we kept a paper ‘key’ underneath so that we would know which was what!
The results aren’t perfect but it turns out the dirtiest thing in the house at the time were …… David’s fingertips! Imagine that!