1 00:00:00,040 --> 00:00:02,400 Speaker 1: I am Scott and I'm Then and we're from car Stuff. 2 00:00:02,440 --> 00:00:05,720 Speaker 1: We're the podcast that covers everything that floats, flies, swims, 3 00:00:05,920 --> 00:00:10,800 Speaker 1: or drives, adventures, thrills, chills literally, planes, trains and automobiles. 4 00:00:10,960 --> 00:00:13,280 Speaker 1: That's right, And you can find all of our episodes 5 00:00:13,320 --> 00:00:17,200 Speaker 1: on Google Play, Spotify, iTunes and really anywhere else you 6 00:00:17,280 --> 00:00:27,560 Speaker 1: get your podcast. Welcome to brain Stuff from how Stuff Works. Hey, 7 00:00:27,600 --> 00:00:30,840 Speaker 1: brain Stuff, this is Christian Seger. So night vision seems 8 00:00:30,880 --> 00:00:33,040 Speaker 1: like a pretty cool idea, right, I mean, you see 9 00:00:33,080 --> 00:00:35,680 Speaker 1: it all the time in movies. Some secret agent type 10 00:00:35,680 --> 00:00:38,800 Speaker 1: straps on a pair of goggles, sneaks into a luxurious 11 00:00:38,840 --> 00:00:43,120 Speaker 1: supervillain compound and mows down enemies under the cover of darkness, 12 00:00:43,240 --> 00:00:47,720 Speaker 1: or the Predator stocks Arnold Schwarzenegger killing his platoon one 13 00:00:47,880 --> 00:00:50,320 Speaker 1: by one by one. And as you're watching all this, 14 00:00:50,400 --> 00:00:54,000 Speaker 1: you may occasionally ask yourself, Hey, do those goofy looking 15 00:00:54,000 --> 00:00:58,280 Speaker 1: goggles really work? Well? The answer is yes, absolutely. With 16 00:00:58,360 --> 00:01:01,279 Speaker 1: a good night vision device or n v D, you 17 00:01:01,280 --> 00:01:04,000 Speaker 1: can see a person standing over two hundred yards or 18 00:01:04,080 --> 00:01:07,320 Speaker 1: a hundred and eighty three meters away on a moonless, 19 00:01:07,440 --> 00:01:11,720 Speaker 1: cloudy night. And whether we're talking goggles, scopes or cameras, 20 00:01:12,160 --> 00:01:14,600 Speaker 1: Most of these devices rely on one or two types 21 00:01:14,640 --> 00:01:17,960 Speaker 1: of night vision, image enhancement that's the green looking one, 22 00:01:18,319 --> 00:01:21,600 Speaker 1: and thermal imaging, which is the bluish gray stuff. They 23 00:01:21,680 --> 00:01:26,080 Speaker 1: both produce results, but work in different ways. Thermal imaging 24 00:01:26,160 --> 00:01:29,959 Speaker 1: captures the upper portion of the infrared light spectrum. Objects 25 00:01:29,959 --> 00:01:33,399 Speaker 1: emit this as heat rather than reflecting it as light. 26 00:01:33,800 --> 00:01:37,000 Speaker 1: Hotter objects, such as the bodies of secret agents, emit 27 00:01:37,040 --> 00:01:40,120 Speaker 1: more of this light than cooler objects like buildings, trees, 28 00:01:40,240 --> 00:01:43,840 Speaker 1: or you know, dead bodies, and that's what you're seeing 29 00:01:43,920 --> 00:01:47,720 Speaker 1: when you use thermal imaging, essentially a measure of temperature 30 00:01:47,760 --> 00:01:51,120 Speaker 1: from negative four degrees fahrenheit to three thousand and six 31 00:01:51,200 --> 00:01:55,960 Speaker 1: hundred degrees fahrenheit. The magic, or well, you know, the 32 00:01:56,000 --> 00:02:00,360 Speaker 1: science starts at the lens, which focuses the infrared lightmitted 33 00:02:00,400 --> 00:02:03,320 Speaker 1: by all of the objects in view and uses a 34 00:02:03,400 --> 00:02:07,480 Speaker 1: phased array of infrared detector elements to create a temperature 35 00:02:07,520 --> 00:02:12,200 Speaker 1: pattern called a thermogram, which is translated first into electric 36 00:02:12,280 --> 00:02:16,120 Speaker 1: impulses and then into data for the display, where it 37 00:02:16,160 --> 00:02:20,000 Speaker 1: appears as various colors depending on the intensity of the infrared. 38 00:02:20,760 --> 00:02:24,919 Speaker 1: Then there's image enhancement. This collects tiny amounts of light, 39 00:02:25,000 --> 00:02:28,560 Speaker 1: including the lower portion of the infrared light spectrum and 40 00:02:28,720 --> 00:02:32,680 Speaker 1: amplifies it. Devices using this approach rely on an image 41 00:02:32,680 --> 00:02:37,440 Speaker 1: intensifier tube to collect and amplify light, both the infrared 42 00:02:37,520 --> 00:02:42,000 Speaker 1: kind and the visible stuff. Image enhancers use a photo 43 00:02:42,160 --> 00:02:47,080 Speaker 1: cathode to convert photons into electrons and high voltage to 44 00:02:47,280 --> 00:02:51,120 Speaker 1: amplify those electrons in a micro channel plate or an 45 00:02:51,240 --> 00:02:54,240 Speaker 1: m c P before they hit a screen that's coated 46 00:02:54,280 --> 00:02:58,359 Speaker 1: with phosphors. Here's the crazy part. These electrons maintain their 47 00:02:58,400 --> 00:03:01,520 Speaker 1: position in relation to the micro channel they passed through, 48 00:03:01,760 --> 00:03:05,680 Speaker 1: which provides a perfect image. Since the electrons stay in 49 00:03:05,760 --> 00:03:09,560 Speaker 1: the same alignment as the original photons. When they hit 50 00:03:09,639 --> 00:03:14,600 Speaker 1: the screen, their energy excites the phosphors, releasing photons. Those 51 00:03:14,639 --> 00:03:18,119 Speaker 1: phosphors create the green image you see when you look 52 00:03:18,160 --> 00:03:24,760 Speaker 1: through a night vision scope. Check out the brain Stuffed 53 00:03:24,800 --> 00:03:27,120 Speaker 1: channel on YouTube, and for more on this and thousands 54 00:03:27,160 --> 00:03:46,200 Speaker 1: of other topics, visit how staff works dot com.