Gray, or Grey, any color formed by blending black and white. Gray tones range from nearly white to nearly black. The many tiny dots of black and white in a halftone reproduction of a photograph produce gray tones.
We first reported on the possibility of an invisibility cloak last year. Now a different invisibility cloak is making the news -- one that uses metamaterials to redirect light away from the wearer.
Whether they're sorting out scrap metal or helping us unlock the secrets of the universe, electromagnets are pretty nifty devices. What's so great about magnetism on demand? We'll electrify you with the details in these videos.