I’ve just returned from SkepchickCON, the mini con inside of CONvergence, where I sat on some panels, dressed up as a Dalek, and spent a not-insignificant amount of time standing in a corner. Don’t worry about that last one, though–it was for a good cause: SCIENCE BOOZE!
My contribution to the rockin’ annual SkepchickCON party was a demonstration of fluorescence. Specifically, I served cocktails that glowed under a black light:
Details, recipes, and videos after the jump!
Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation (or as Wikipedia puts it: “Fluorescence occurs when an orbital electron of a molecule, atom or nanostructure relaxes to its ground state by emitting a photon of light after being excited to a higher quantum state by some type of energy.”) The most striking examples of fluorescence occur when the absorbed radiation is in the ultraviolet region of the spectrum, and therefore invisible to the human eye, but the emitted light is in the visible region. This is what’s happening when objects glow under a black light.
Quinine is a substance famous for its anti-malarial properties and for giving tonic water its bitter taste. It turns out that quinine is very sensitive to ultraviolet light, thanks to the presence of divalent europium, a fluorescent activator that emits blue light. We can use this information to our advantage. I give you the Teal Armstrong (named by the talented Marian Call):
Marian Call tries the Teal Armstrong. Photo by Topher Hunter
Quinine has uses beyond the medical and the culinary. The efficiency of the fluorescence process, defined as the ratio of the number of photons emitted to the number of photons absorbed, is called the fluorescent quantum yield. The quinine salt quinine sulfate is a common fluorescence standard, against which the fluorescent quantum yields of other substances are measured.
Speaking of other fluorescent substances: one that is very important to our health is riboflavin, also known as vitamin B2. In addition to playing a key role in energy metabolism, it looks damn cool under a black light, giving off a yellow glow. Behold the Pinky Nelson (named by Maggie after George Nelson, an astronaut from Minnesota):
FYI: glow sticks are phosphorescent, not fluorescent. Photo by Bonnie Burton
Shining a UV light on riboflavin actually has practical use: treating blood pathogens. When UV light is applied to blood products, like platelets and plasma, containing riboflavin, the nucleic acids in harmful pathogens are damaged, rendering them unable to replicate and cause disease.
Riboflavin is destroyed by exposure to ultraviolet light, so you’ll have to rely on the other vitamins in the liquid B12 for any possible health benefits. However, if you drink enough of it, you’ll end up with bright yellow glowing pee, so there is that!
and you can see the riboflavin effect a little more clearly in this video I made at home:
I had a TON of fun performing my demo at SkepchickCON. Party-goers would come up to my table looking for alcohol, and I would tell them, “In this room you have to learn a little science before you get to drink,” to which all but one person responded, “AWESOME!” It feels great to entertain and educate at the same time, especially when people are receptive to what you’re doing. It’s something I do a lot (including at my day job), but I was extra proud of myself for coming up with a show that fit the event so perfectly, and I was thrilled to be supporting a cause that’s so important to me.
Photo by Topher Hunter
Do it yourself!
To make the Teal Armstrong, combine 1 part vodka or gin with 3 parts tonic water and apply UV light.
To make the Pinky Nelson, combine 1 part vodka with 3 parts cranberry juice, then add a drop or two of liquid B12 vitamin (we used 1 drop per ounce of mixture) and apply UV light.
If you invent any new concoctions using these ingredients, be sure to share them in the comments! And if you’re here because we met at CONvergence, be sure to say hi! I’ll see you there next year!
Featured image by Topher Hunter