Water. Without this invigorating liquid, we'd be in trouble. To be more precise, we wouldn't be at all, since we require water to exist. The same goes for more or less every being on Earth. But water is not only excellent at keeping us alive (especially when mixed with coffee!), it also allows us to be reborn every morning in the shower.

The Dihydrogen Monoxide Shower Curtain will teach you everything you need to know about water: its molar mass, its density and many other features of H2O. The small molecules in the background even match the respective aggregate phases (solid, liquid, gas). And don't worry - the cumbersome "dihydrogen monoxide" is also just an unusual and rarely used term for water ;).