How small are mites: the Full Stop Test

8 Oribatid mites scaled to a 12 pt Times Roman period (0.5 mm dia.)

Recently The BugGeek posed an interesting challenge: “Can you talk to 10-year-olds about science?” I found this especially interesting because, as an acarologist, I find it difficult to explain the study of non-pest mites to people of any age or educational level. Usually when asked my occupation, I just say ‘I’m a scientist’ or, if among university types, ‘a biologist’ or ‘I work on bugs’. Other than with voluble taxi drivers, this usually proves satisfactory. Sometimes (usually under the influence of alcohol) I do try to explain to strangers the excitement I feel about the diversity of intricate morphologies and amazing behaviours exhibited by mites. But in my experience, if you have a party that has been going on for too long, then I am just the person you need to send even the most couch-bound inebriate scratchingly on their way.

A few years ago, though, I was asked to try and explain mites to 2nd Graders. I decided that the critical information was size – if I could explain how small mites were to an 8 year old, then I’d have a chance. I played around with a how many mites would your foot-print cover (a number too large even for a government deficit) and a penny, but even a penny can hold about 7000 of the smallest mite in the picture above and even in a large poster the mites are too small to see. I finally settle on a Times Roman 12 pt period, conveniently 0.5 mm in diameter. Times Roman and similar serif fonts are those most commonly used in publications (the little feet make a sort of dotted line for the eye to follow while reading) and every sentence ends in a full stop. What could go wrong?

Well, the good news is the 2nd Graders liked the pictures of the mites. The bad news is that ‘period’ does not compute in the 8-year-old mind. We tried inverting the background so that the period was black and the background white (which involved several hours of cleaning up black speckles), but ‘what’s a period?’ proved too great a hurdle. Oh well, it still makes a nice poster.