Suppose you found a few LEDs behind glass.
Ugh; working on submitting a proposal this week, but I'm trying to be good and at least post some kind of update every day. Today, a random thought inspired by an installation in Millenium Park from my trip to Chicago a few weeks back.
It turns out that, if you're Richard Daley, this is what you do with a bajillion LEDs.
Okay, I lied. There are actually a goodly number of the things here, behind glass bricks.
LEDs are all kinds of neat devices. Using semiconductor engineering to harness the magic of quantum mechanics, Light Emitting Diodes turn electricity directly into light, commonly with better than 90% efficiency. In an incandescent light bulb the light is got out by brute force, by heating a strand of wire until it glows white hot. Like, hotter than the surface of the Sun hot. A light bulb makes a grand radiant space heater, in fact, but less than 10% of the energy you put in comes out as visible photons.
Actually, you appear to be standing in front of a wall of LEDs behind a wall of glass bricks.
Ultimately the hope is that by using LEDs places like North America, Europe, and Southeast Asia that light up the globe like an ornament in space, drastically less power will be consumed by electric lighting. Before that can happen the white LED has to be perfected and the price needs to come down. Thanks to their quantum nature LEDs are much better at generating single spectral wavelengths of light, rather than the mix needed to appear white. They're already revolutionizing light in certain niches, however. The bulky D-cell powered flashlight will soon be extinct, for one thing, as hopefully will be the nuisance of finding that your flashlight's batteries are dead only after the breakers trip. Also, LEDs make it economical to build things that are always lit.
Holy mayoral vanity project, Batman, that's a lot of LEDs!
Oh! That's what you'd do? Really?
The other big advantage to LEDs it that, even when constantly lit, they can last literally decades before wearing out. This comes in handy in remote areas. Turns out, one surprising obstacle to human advancement in the developing world is the lack of artificial light after sunset in regions without electricity. An extra hour or two of light after outdoor activities come to an end means time to read books or newspapers or teach children. Not having to do this with crude kerosene lamps is a major boon to public health and safety. The Light Up the World Foundation is devoted to installing virtually indestructible solid state lighting systems based on LEDs combined with solar panels, pedal generators, or miniature wind or water turbines.
Which brings us back to the installation at hand. A low-power, highly rugged light source has plenty of applications right here in urban North America, too. In fact, LEDs work well nearly anywhere one might want to run a constant source of light, especially if you need a large number of them, or if they're hard to get access to, because in those cases changing bulbs that burned out becomes a major project in itself. Hence the gradual changeover of most traffic signals to LEDs, and the proliferation of LED display roadside billboards. And in Chicago, for reasons nobody quite comprehends, two enormous walls that display a constantly rotating selection of peoples' faces, every minute of every day.