Antibubbles

Hey Matt:

I noticed a weird thing the other day while having a pint of Carl Strauss: I could swear some bubbles were actually sinking. Is that possible? What gives?

-- Rob, the net

Oh, the elves loved figuring this one out. We thought for a minute we had a real breakthrough-- sideways bubbles-- but it turned out that the elf in question couldn't lift his head up off the table and was just looking at the glass cockeyed. So much for elf science. The whole experiment dissolved into a bar fight anyway, so we had to fall back on the work of others. And many others have investigated this phenomenon, though you'd think somebody at Stanford would have more important stuff to do. Actually, the whole thing is pretty simple and should work with any drinkable that creates small enough bubbles. If bubbles in the center of the liquid are rising fast enough toward the surface, they set up a kind of current that flows up the middle, across the top of the drink and down the inside of the glass toward the bottom. Any bubbles clinging to the glass that haven't sucked up any of their neighbors and are still tiny, not big enough to counteract the current and float up, can move down the glass with it. Bingo. Antibubbles. Conditions are ripe for this for only a short time after the drink is poured, so get those bar bets on the table in a hurry.