WEBVTT 00:00:00.000 --> 00:00:04.640 If you've ever been bored at an airport, you've probably spent some time staring out the window 00:00:04.640 --> 00:00:09.200 at the airfield. Occasionally, you might have noticed a plane that looks vastly different than 00:00:09.200 --> 00:00:15.200 the others, like Korean Air's sky blue paint jobs, Spirit Airlines' obnoxious yellow livery, 00:00:15.200 --> 00:00:21.200 or maybe one of all Nippon Airways' Pokemon themed jets. These designs really stand out 00:00:21.200 --> 00:00:28.000 in a sea of plain white planes. But that leads us to an obvious question. Why is white the default 00:00:28.000 --> 00:00:33.920 color for passenger airplanes? Corrosion control is essential when firing a metal tube through 00:00:33.920 --> 00:00:39.280 the atmosphere at over 500 miles per hour on a regular basis, which is the primary purpose of 00:00:39.280 --> 00:00:44.720 a plane's paint. Prior to the 1950s, planes weren't typically painted white. In fact, 00:00:44.720 --> 00:00:50.240 they often weren't painted at all, just regularly polished, because the paints available were heavy, 00:00:50.240 --> 00:00:56.240 expensive, and didn't adhere well to the metal fuselage. But primers and paints gradually improved 00:00:56.240 --> 00:01:01.440 in adherence and durability. Bare metal required polishing roughly three times annually, while 00:01:01.440 --> 00:01:08.080 a new coat of paint is only needed every few years, making polishing around 0.06 to 0.3% 00:01:08.800 --> 00:01:14.560 more expensive. And that's reason enough. But paint can add significant weight to a plane, 00:01:14.560 --> 00:01:20.320 so paint for commercial aircraft is ideally both durable and lightweight. According to Boeing, 00:01:20.320 --> 00:01:27.200 the typical white paint on a large commercial aircraft like a 747 adds up to 555 pounds when 00:01:27.200 --> 00:01:33.440 dry. It's a tiny fraction of the overall weight of the aircraft, but every pound of weight increases 00:01:33.440 --> 00:01:39.360 the fuel burned during takeoff and flight. That's part of why most airlines charge fees for luggage, 00:01:39.360 --> 00:01:44.320 because regardless of whether you pack less or pay up, they're maintaining their profit margin. 00:01:44.320 --> 00:01:48.800 However, there's a common misconception that paints that are lighter in color are also lighter in 00:01:48.800 --> 00:01:54.000 weight, and that's why planes are painted white. While it's true that a higher concentration of 00:01:54.000 --> 00:01:59.600 pigment will result in heavier paint, the total weight depends on the specific pigment being used, 00:01:59.600 --> 00:02:04.960 not necessarily the color. But if white paint isn't any lighter weight-wise, why are so many 00:02:04.960 --> 00:02:10.800 planes white when they clearly don't have to be? White paint has a high albedo, meaning that it 00:02:10.800 --> 00:02:15.680 reflects most of the light that hits it, while darker pigments absorb sunlight. This means that 00:02:15.680 --> 00:02:21.040 dark paint leads to excess heat and more fuel expended on cooling the cabin so you don't bake 00:02:21.040 --> 00:02:26.400 like a potato during your trip. And that extra fuel again costs the airlines more money. Dark 00:02:26.400 --> 00:02:32.080 paint is also likely to accrue sun damage faster, basically the opposite of how it works for people, 00:02:32.080 --> 00:02:37.520 because the dark pigment absorbs more UV radiation, which breaks apart the molecules in the paint. 00:02:37.520 --> 00:02:42.320 Minimizing damage and heat from solar radiation is also why satellites, space shuttles, and the 00:02:42.320 --> 00:02:48.640 international space station are white. We usually think of space as really cold, but since the vacuum, 00:02:48.640 --> 00:02:53.600 there's no atoms floating around to allow heat transfer in the form of conduction or convection, 00:02:53.600 --> 00:02:59.680 which means that a black surface in space can get insanely hot when exposed to solar energy. 00:02:59.680 --> 00:03:04.720 White paint also has other advantages. While military planes are often painted gray to blend 00:03:04.720 --> 00:03:10.400 into the tarmac or a hazy sky, commercial planes need to be as visible as possible on the tarmac. 00:03:10.400 --> 00:03:15.680 Some runways are busy 24-7, even in terrible weather conditions. And while collisions are rare, 00:03:15.680 --> 00:03:20.960 that extra visibility matters. White paint also makes it easier to spot cracks and other kinds 00:03:20.960 --> 00:03:26.880 of damage to the aircraft exterior before packing them with people. Generally a good idea. And that's 00:03:26.880 --> 00:03:32.400 why commercial airplanes are white, because it reduces heat, saves money, and increases safety. 00:03:32.400 --> 00:03:38.560 Now, if only they could increase the leg room. Am I right? Okay. Hey, if you're the type that 00:03:38.560 --> 00:03:42.080 wonders why other things are the color they are, go check out this video next, 00:03:42.080 --> 00:03:45.920 where we explain why so many circuit boards are green.