Stories tagged night vision

Dec
13
2008

A night vision fox?: The perfect weapon.
A night vision fox?: The perfect weapon.Courtesy Josh Russell
Weariness toward the younger generations is usually more Gene’s territory than my own, but I couldn’t pass this up.

Not that Gene himself is necessarily weary of younger people… I don’t want to put words in your mouth, Gene, it’s just that I came across this story of a local gentleman taking “stay off my lawn” to glorious new heights.

It seems that a 50-year-old man from Willmar, Minnesota, was fed up with the repeated toilet-papering of his house by young nogoodniks, and decided to take matters into his own hands on the nearby high school’s most recent homecoming night. (And before y’all get all up-in-arms—you know who else took matters into his own hands? John Rambo. And, like, George Washington. We don’t hold it against them, do we?)

Anyway, this modern day Michael Douglas, who we’ll call “Scott Edward Wagar,” wasn’t content to hide behind the bushes with the garden hose. Instead, he got all high-tech—using night-vision goggles, Scott Edward Wagar ambushed a group of teens approaching his house, and sprayed them with a supersoaker squirt gun filled with… fox urine!

Oh, man… not since The Boy Who Could Fly

After the urine dousing, things got pretty confusing. There was something about a struggle and a hurt finger… the events aren’t totally clear to me. The next day, however, Scott found a dropped cell phone on his property and held it for ransom, and there was some yelling and screaming involved. I’ll try not to think about that part too much—Wagar was probably drunk on the heady brew of victory at the time.

So what does this have to do with science? Not a whole lot, really, but we could go over Wagars arsenal in a sciencey sort of way.

So… night vision goggles. Human’s natural night vision relies on the maximum dilation of the pupil (to allow as much light into the eye as possible), and a molecule in the eye called rhodopsin. Rhodopsin in our retinas is extremely sensitive to light—according to Wikipedia, at least, it’s responsible for more effective light capture in the rod cells of the eye, or for more efficient light-to-electrical energy conversion. Either way, it takes about half an hour in the dark for rhdopsin to build up to maximum levels. The instant that rhodopsin is exposed to white light, however, it bleaches and loses all night vision enhancing properties.

What are we poor, night-blind humans supposed to do? Night vision goggles! We’re all familiar with night vision technology, thanks to our rad action movies, but it turns out that there are multiple kinds of night vision goggles. “Active infrared” night vision works by emitting infrared light, which is invisible to human eyes but can be picked up by the goggles and converted to visible light. The thing is, active infrared can be seen by other night vision goggles like someone waving a flashlight around, so if any of those kids had infrared vision, the gig would have been up for Scott Wagar. That’s why there’s also…

Themal vision goggles, which we also know about thanks to our rad video games, work by making tiny temperature differences visible—the heat emitted by a living body (or any object that isn’t totally frozen) is, again, represented in visible light by the goggles. And because the goggles use the radiation emitted from other objects, instead of shining radiation (i.e. the infrared light used by active infrared goggles) on other objects.

Finally, there are “image intensifier” goggles. These work by detecting tiny amounts of ambient light (it’s rare that you’d be in a situation that is absolutely dark) and intensifying it. When photons (light) enter the goggles, they hit a detector plate, and each photon causes an electron to be released from the plate. These electrons are accelerated by a magnetic field in the goggles, and hit another plate, causing a whole bunch of electrons to be emitted, which then hit a phosphor screen to make an image (this is the same way older TVs make images—through electrons hitting a phosphor screen. The image that is displayed by the goggles to the wearer is in monochrome (one color), because the detector plates in the goggles don’t distinguish between the wavelengths of the photons hitting them—that is, all colors of light entering the goggles are just detected as light, not colored light. We know about this kind of night vision though rad movies also—you know when some guy with a gun and night vision goggles walks into a room, and then some other guy with a gun and probably no night vision goggles flips on the lights, and the first guy gets all blind because there are so many more photons hitting the detector plate in his goggles, and more electrons are being released, and the phosphor screen gets really bright in his eyes, and then he probably gets shot or knocked on the head with something by the second guy. It makes more sense now, doesn’t it?

I’m guess Wagar had some sort of image intensifying goggles.

As for fox urine… Well, I hear that it’s super stinky. I was going to get more into what makes it super stinky, but this whole post has taken me way longer to write than I had originally intended. If you’re really into animal pee, though, and foxes in particular, there are plenty of resources out there for you to examine. Like this. Or this. Or this, I guess.

Scott Edward Wagar, you have amazed us all. And, kids, when someone gives you the old “And stay off my lawn,” maybe you should take it seriously. (Or you could start carrying bright strobe lights, rain jackets, and water balloons full of something worse than fox pee when you plan on TPing someone’s house.)