If you look closely at a glass of freshly poured Guiness (or any beer--but it's easier to see in a dark ale), you'll notice that some of the bubbles are actually falling instead of rising. Explain how this is possible.
Perhaps if you already had one too many, you were observing the bubbles upside down. Relative to your observing, the bubbles were moving in a downward motion! :)
Or maybe that's beer nuts floating downward??? lol
Relativity
