There’s nothing tiny about the international controversy brewing over the safety of nanomaterials. In April, a German company recalled a tile sealant called Magic Nano after dozens of consumers suffered breathing problems while using it. Never mind that the product contained particles too large to actually count as nanomaterials (which must be smaller than a billionth of a meter)—the scare was on, and European confidence in products labeled “nano” had already sunk.

Launch the slideshow to see how titanium oxide reacts with light to zap dirt at the molecular level

Not so long ago, chemical engineers discovered how to use titanium dioxide to keep buildings free of discoloring pollution.

A baseball zooms through clouds, straight through a wall and into the waiting hand of actor Adam Smith, who is tricked out like a magician, complete with wand, tuxedo and top hat. “How do you do it?” Smith asks conspiratorially. “You just need a small enough ball, of course.” But Smith isn’t really explaining a magic trick. He’s talking nanotech, in the new short film When Things Get Small.

The most prolific car manufacturer on the planet resides in a Rice University laboratory in Houston, where chemist James Tour and his colleagues have built one trillion trillion nanoscopic cars. The tiny four-wheeled vehicles are only four billionths of a meter wide-25,000 of them parked side by side would be about as thick as a piece of paper. Not just another nano-gimmick, Tour´s cars could one day carve tiny channels in silicon, creating more-powerful computer chips.