Foil Wrappers on Bubble Solution. Useful? An Empirical Test
Last year, I made brief and horrible fun of the foil wrappers they put on bottles of bubble solution. I snarkily asked whether there was a terrorist plot to inject bubble bottles with cyanide. In a comment, the ever-thoughtful John Stracke suggested that “it probably improves the shelf life, by keeping air out better than just a lid would.”
Yes, that would make sense. But is it true? To find out, last May I bought two bottles of Imperial Super Miracle Bubbles. I immediately tore off the foil seal of one of the bottles, then replaced the cap. The other bottle I left alone. For a year and a month, the two bottles remained side-by-side on my kitchen shelf, waiting, waiting…
… for yesterday. After I had left the room, my ever-loving wife marked one bottle with an “X,” wrote down on a slip of paper whether the “X” referred to the bottle that had kept its foil or the bottle that had lost its foil a year ago, hid the slip of paper at the bottom of a drawer, then took the other foil off and gave both bottles to me. This is called “blinding” and ensures that any observers’ biases won’t influence the count, since we wouldn’t know which bottle was which until we consulted my wife’s secret key after the experiment. I guess you could say the experiment was “double blinded” because the bottles didn’t have any eyes.
I took the bottles over to our front stoop where my two kids sat, their breath at the ready. And breathe they did, oh yes. We took turns, with one of us blowing bubbles and the other two of us counting the bubbles as they came out of the wand and floated about. When the counters counted different numbers of bubbles, we took the average of the two counts. With three blowers and two bottles, we had six different results to report:
Average number of bubbles per blow for Bottle “X” (8 blows): 16.4
Average number of bubbles per blow for the Other Bottle (10 blows): 14.3
Average number of bubbles per blow for Bottle “X” (10 blows): 8.1
Average number of bubbles per blow for the Other Bottle (14 blows): 6.7
Average number of bubbles per blow for Bottle “X” (7 blows): 17.1
Average number of bubbles per blow for the Other Bottle (7 blows): 21.3
Without knowing which bottle — Bottle “X” or the Other Bottle — had the foil taken off a year and a month ago, you should already be able to spot a problem: for the two kids, Bottle X gave out more bubbles on average than the Other Bottle, but for Dad (me), Bottle X gave out fewer bubbles per blow than the Other Bottle. That’s an inconsistent result across the three bubble-blowers.
Once we unwrap the slip of paper, the results get more dismal for the foil-as-quality-protectant hypothesis: Bottle X is the bottle that had the foil taken off a year and a month ago, and the Other Bottle is the one that kept its foil until just before we started blowing bubbles. For two out of three bubble-blowers, the bottle that kept its foil produced fewer bubbles, not more bubbles as you’d predict.
In conclusion, our experiment provides no support for the hypothesis that the foil on the top of bottles of bubble solution acts to protect the quality of bubble solution over long shelf periods (at least as long as a year and a month). Since common sense tells us that bubble solution is not for human ingestion, the foil can’t be there to protect against terrorist cyanide injections either.
So why do they put foil on the top of bubble solution bottles? What is the foil there for? We’ve eliminated one possibility, but the mystery remains unsolved! Cue music.