Three Percent Nothing

While studying the chemical element boron, I came across this sentence in Wikipedia:

Borosilicate glass, which is typically 12–15% B₂O₃, 80% SiO₂, and 2% Al₂O₃, has a low coefficient of thermal expansion giving it a good resistance to thermal shock.

I noticed that the best you can get to with 15+80+2=97 percent.

So the only reasonable eXplanation is that it is 3 percent Nothing.

So the neXt time your chemistry lab partner makes a remark like, "Gee, your beakers are reaLLy shiny." - just say, "That's because they're at least 3 percent nothing! ... maybe as high as 6 percent nothing!"