You’ve probably noticed that as a soap bubble thins, it acquires a rainbow of iridescent colors across its surface. Or perhaps you’ve noticed that a film of oil on a mud puddle shows beautiful colors. These are common physical properties of thin film interference.
The way it works is that light entering a material with a higher refractive index is both reflected and transmitted. Some of the light bounces back with a partial phase shift, and some of it passes through. In a thin film, it passes through but doesn’t travel far before it hits another boundary, for instance between the film and the water underneath it, and again, some of it is reflected and some transmitted. This second reflected beam of light, though, is out of phase with the first, by an amount that depends on the thickness of the film. What that means is that certain wavelengths will be shifted in such a way as to reinforce the first reflected beam, generating constructive interference that will make that wavelength brighter. Other wavelengths will be shifted the same amount, but they will be out of phase with light in the first reflected beam — there will be destructive interference, and that wavelength will be damped out.
The net result: the light reflecting off the film will be colored, and the color will depend on the thickness of the film. It’s a simple physical process. Cephalopods use it to generate their colors — just by shifting thin reflecting membranes by a tiny distance of a fraction of a wavelength of light, they shift which wavelengths constructively and destructively interfere with each other, and thus change their color. Now engineers are exploiting the same principle to build television screens: they use a thin film that can be expanded by fractions of a wavelength of light by applying a voltage to build reflective color screens. This will be very cool. If you’ve got a Kindle or one of the other e-book readers, you know they use a reflective screen with no backlight that depends on ambient lighting to be visible…and that right now you only get shades of gray. With this technology, we’ll be able to have color electronic paper. I’ll be looking forward to it.
Unfortunately, we’ll also enable incomprehending gomers. Case in point: Casey Luskin thinks that thin-film interference patterns implies design. Well, actually, it’s stupider than that — he actually thinks that because TVs are being designed to use thin-film interference, and because cephalopod skin uses thin-film interference to generate color, that implies that cephalopod skin is also designed. I kid you not.
So we may soon have affordable, energy-efficient, cuttlefish inspired flat screen TVs and computer monitors everywhere. But of course, there’s no design overtones to see here folks. None whatsoever.
Right. And because trebuchets were designed to use gravity to generate force, and because rocks on mountains will tumble down due to gravity, avalanches are therefore designed. We make fire by design to produce the release of energy by rapid oxidation of carbon compounds; cells also oxidize carbon-containing compounds to produce energy; therefore, cells must have been set on fire on purpose. This is what the IDiots are reduced to: if something designed and something evolved make use of the same properties of our common physical universe, that means the evolved object must be designed, too. It’s ridiculous, but it’s all they’ve got.
