There are some techniques in the lab that attract mishaps, just as some people are particularly accident prone. When those two elements combine, adventures abound. I am, of course, of the accident prone league, which is why spreading my plates with a glass rod was always a recipe for disaster.
But I get ahead of myself.
My non-science readers are currently wondering what this fantastical plate spreading must entail. If it creates mishaps it must be fancy, or technical, at least involve liquid nitrogen, and goggles and lab-coats. It is none of those things (although I could easily write an entire blog post about liquid nitrogen mishaps as well).
Plate spreading, as basic and standard as any lab technique can be, is a way to evenly spread a concentration of bacteria (or yeast, or whatever you are working with), onto the plate on which it will grow. In most cases you have diluted your culture enough that there are not enough organisms to cover the entire plate. Instead, they will spread out evenly as microscopic dots, each dot then dividing and replicating to create a population of cells that grew out of one original organism. Each population will be distinct from the next, and is called a colony.
The traditional method to do this, which I used frequently when I began my science career, was to take a glass rod, dip it in a pot of ethanol, flame it to sterilize it, and then streak the plate with a back and forth movement with one hand, while rotating it with the other (scientists, ever the mother of invention, have even designed a rotating plate to facilitate the turning- think dim-sum tables, but smaller.)
The astute among you have already gathered the problem with this technique. For the rest of you, of the non accident prone league, understand that for some of us, dripping flaming alcohol and pots of flammable substances do not mix well. Inevitably, a flaming drop from the rod will land in the ethanol container and set it on fire.
The first time this happened to me as an undergraduate, I thought the world was about to end. I looked panic stricken at the post-doc instructing me, expecting him to banish me immediately from this lab and all others (after rescuing his key note books and favorite grad-student from the burning building of course). Instead, he simply placed a cover on the ethanol container and the fire promptly went out.
So problem solved, right? For the non-accident prone, absolutely. For the rest of us, you must remember two other key elements. The first, make sure the lid you place on the container is not flammable itself. A pretty basic rule, no doubt, but when faced with the rising flames a petri dish lid sitting next to the container, that is exactly the right size, might look tempting. Do not succumb. It will only melt horribly into the ethanol, fueling the flames and creating a smell that will attract all senior lab members from all corners of the building, drawn to the scent of disaster.
Secondly, although others can get away with taping reagent recipes and even Kleenex boxes to the shelf above their benches, we cannot. I once set my ethanol on fire and extinguished it successfully, only to the find the Kleenex box secured to my bench in flames. When I say secured, I mean secured. As I tried to remove the box before it ignited the note-books above it, I wondered why I had felt the need to fasten it as if I was tieing my belay rope for a death defying climb.
I then ran, in a manic flurry reminiscent of a Charlie Chaplin movie, with the now rectangle of fire to deposit it in the nearest sink. Crisis averted, I collapsed on my bench chair in exhaustion and relief, only to notice the grad-student behind me looking intently into his microscope- he had not noticed a thing.
This is the type of concentration and focus us accident prone lab members must seek to emulate.
This being my history with the flaming rod, you will now understand how I felt when introduced to the glass bead- pictured above. Instead of the intense procedure described above, a few of these pre-sterilized beads are decanted onto the plate, the plate is shaken briefly, and then the beads are tipped out, to be washed and reused. No flames, no ethanol, no disasters, no heart attacks- just a few shakes, some fun rattling, and done.
I love glass beads.
Again those among you of my ilk may see the possibilities in this. Yes, spilling them is somewhat of a disaster, and yes I have done it. But no, I have not yet come running into a room, encountered the glass beads on the floor, and tread in place on them several times before crashing to the floor. I say not yet. I know to never say never.