His appearance says 1960's bully, while his words say nerd. His studio says late 90's TV show, his jokes say biology teacher. His outro music says 1980's instructional video, his cat says nothing. Alec you're all over the place. Just as you should be.
Ex truck driver here. I've never had issues reading signs at night, unless it had fine print. For example, while driving in New Jersey, I saw a sign that read, "Garden State Parkway," but I didn't see the tiny writing on the bottom of the sign that read, "no vehicles over 5t GVW." That didn't end well...
Truck driver here. Yeah I never understood why they would use fine print. I've also seen some that have more words than a harry potter book on just one sign. How am I suppose to read that when the speed limit is 70. Another one I have a problem with is when they put bright flashers on the sign. Can't read it til you're about to pass it. Luckily most of the time you can guess what it means based on the shape. I now just run in the Texhoma region so the first few times I slowed down a bit and was careful but now I've memorized them
@@Gamerdude753 I know right? Whoever designed these signs needs to try to read them at speed. "US 209 Closed to commercial traffic beyond exit..." zoom! "Wait, beyond exit what?!"
@@Trainfan1055Janathan A pet peeve of mine is also when they require proper understanding of the local language. For example here in Austria there are occasionally 30km/h speed limit signs in villages with „Gilt nur für Heizöltransporte“ (“only applies to fuel oil transports”) below. Even if you know a bit of German it’s unlikely you’ll know that word.
@Michael K That's how I got two tickets in two mornings in a row in Belgium. A sign in only Flanders and no symbol of any kind that made a local street conditionally one-way.
My fiancée is a truck driver (18-wheeler,) and we are currently driving at night. So excited to hear you ask what we see from a truck cab! The reflections look just as bright to both of us as they do from a car. We love your channel!
Truckers can see the reflectors just as well. They "fade" sooner though, but it's not an issue since they've served their purpose at that point. (Source - me: trucker for 6 years) Fun fact - a lot of road paint also has glass beads in it in order to create a reflective surface. (Source - me: road painter for...about a month) (edit... Oh... You covered that...I commented too soon. I should have known you'd cover that... Ok :)
Near my house they were painting last month and after throw some paint they covered it with a clear sand. After some asking the clear sand its in fact glass beads.
@@mauriciomarianocarneiro when I was doing it, our sprayers had a reservoir for the beads. It would drop those as it was spraying. Most of the time we would also have to do exactly as you just said because it would sometimes clog up, and it would almost always run out of beads before paint.
I used to live next to a place where those big green interstate signs were made. They probably did other stuff too but those glass beads were always on the ground outside it.
It's quite a sight from the cab of a fire engine heading to an emergency at 3 in the morning when no one else is on the road. Every road sign, mile marker, mailbox reflector and driveway marker reflects your emergency lights right back at you and makes the world look like a giant red-themed disco club.
One of the things I appreciate but sometimes fail to remember is the standard reflective house number signs installed by the roads and safety departments.. especially helpful in heavy drifts of snow (making low signs irrelevant) kind of a similar concept to a housing addition I lived in, the curbs were concave (inward?) and near the driveway, sometimes under the mailboxes, the house number was painted reflective on black in the curb.
Oh my God, I hate myself for not figuring that out on my own. That's punny! (though in my defense, I was thoroughly distracted with the r/cursedimage in the mirror to think about puns at that point)
Can we all just take a moment to appreciate the dedication it took for him to hold that face the entire time the mirror was panning across? He made damn sure that gag landed.
No! Please don't. Then every episode will take at least 3 times as long as after every commercial break, they will tell you about 1/3rd of what they told you before the commercials because they think the viewers are stupid.
@@loturzelrestaurant Well you may ;) But I hardly have the time to watch it next to all the others like Tom Scott, ElectroBOOM, Bigclive and Technology Connections ;)
I drive a truck, despite the headlights being 6' lower than my eyes, retroreflectors work very well and I am very grateful they are a thing. Especially cats eyes. Thanks for the videos
The "wrong way" lane reflectors (potentially) saved my life once! I moved to a new city with much bigger and wider roads with a lot more lanes on each side than I was used to. One time I was driving at night and I went through a huge intersection with multiple entrances and exits to the highway and I went down the wrong direction - fortunately there was almost no one else around anyway because it was late, but I realized my mistake almost immediately because suddenly the whole road was covered in red light.
I still say retro reflective tape is best used to put eye shaped cutouts high in trees overhanging roads and bicycle trails in sketchy, poorly lit areas.
In my job as a paint chemist I formulated retroreflective paint for use on railcars. The tiny glass beads used in the paint had a weird property: they were extremely slippery. A small amount spilled on the lab floor turned it into an ice skating rink.
Much worse than an Ice Skating Rink. When one happened to fall on a floor of these tiny tiny glass beads it could be described a 'poetry in motion' given the poetic words that were called out after a painful landing.
Silica gel beads do much the same on linoleum. They also bounce in a way that's very satisfying if you're bored and working late in a discount retail store as your first job in high school. Allegedly.
I did a small stint of road painting one season and it will make everything slippery regardless of the surface and a lab floor sounds like a nightmare... Ohh and a small PSA for anyone who wants to use the stuff you want to wear goggles/glasses or some face covering so you do not get it into your eyes. I mean this sincerely because it's not like sand these little bastards will roll around your eyes for days and water only helps so much.
The reason they often don't use a retro reflector on garage doors is because, like you also mentioned in your video, cars also have these reflectors, so they might cause false signals for the sensor. I have had this as an driver of a first responder vehicle wich had retro reflective striping. The sensor registered it's signal bouncing of from the striping and the garage door closed on top of my ambulance. They quickly converted the system to the set-up with the LED and the receiver on seperate ends.
Ah, does make sense. But then: It would be easy to put the retro reflector at the end of a small black tube or shielding, so the angle it reflects back is limited to wherever the open end points to. Makes alignment much easier and tolerant.
@@JouMxyzptlkThe issue isn’t the reflector the sensor is supposed to see, it’s all the reflective things that the sensor isn’t supposed to see. For example, the reflective logos on someone’s running shoes could be misinterpreted as “all clear” as the garage door closes on their foot.
@@JouMxyzptlk also shouldn't be too difficult to have a "calibration" button that would save the strength of the returned signal and not accept stronger signals (edit: ie. you put your system in place, press "calibrate", and it no longer accepts stronger signals until "calibrate" is pressed again)
A few decades ago, my family went on vacation to England. The road sign “cats eyes removed“ was one of the more unsettling road signs we’ve ever seen, but it’s nice to know that there’s a reasonable explanation!
Try learning they're called cats eyes when you're 7 years old. That's unsettling too, because it's pretty obvious cars drive over them. Getting used to that and other things is why I laughed almost as much as @@Valery0p5! XD
In the late 90's with the dawn of the digital photography age... and as advancements in ink came along anyway... There was a very fine tipped felt marker that showed up in Walmart's "craft" section, called "Pet Eye Remover"... AND probably the same product was released somewhere else as a "Red-Eye Remover" for photographs... My little brother picked one of them up and asked almost instantly "What's a pet eye remover for?" AND before my mother could have a CHANCE to think, I felt inspiration hit, and threw myself into vibrant demonstration... "Come 'ere ya' little bastard!" I scooped up an imaginary small animal and proceeded to stab violently and make a sickening squishy-pop sound (as kids are prone to do)... Now, here's where I explain that the ENTIRE FAMILY were members of the local Humane Society... AND we had been active for over a decade by that point, even part-timing as volunteers for animal control, to make house calls, whether for picking up strays or investigating (at least as preliminary) for abuse allegations... or just to help out pet owners who were having trouble... SO we'd all been around a bend or two, and there was a somewhat callous edge to all our humor as we've all "seen some sh*t" along the way... BUT the several elderly ladies and a couple employees of the store did NOT know that part of the story. They just saw and overheard my dubious "conversation" with my little brother, and our mother CRACKING UP at the antics, even while (of course) my brother shot a look sort of like a whipped puppy for a moment and protested "NO!" Of course, that was before he thought better of himself and realized "Yeah, once again your older brother is pulling your chain..." At any rate, as we carried on down the aisle, having returned the "Pet Eye Remover" pen to the little bin on the shelf, there was a near-stampede over to examine this ghastly invention and probably an inquisition of the poor employees as to WHY THE F*** would Wally World even stock such a HORRIFIC device... Maybe not, but we were back within a month and there were NO MORE "Pet Eye Removers"... SO I can quietly enjoy the tiny satisfaction that maybe I did "get at" Walmart... I don't know. ;o)
It just occurred to me, this video explains why signs are BLINDINGLY bright when I'm driving my Miata at night. First of all, you are seated VERY low in the vehicle. Your head is at door handle level compared to most other vehicles. Secondly, the car has headlights which pop-up into a position that is almost the same height as your eyes while seated in the vehicle. Meaning, this is one of the few cars where your eyes and your headlights are very close to the same position, making the signs appear brighter for longer than basically any other vehicle I've driven. Now I know why. Thanks for the education.
NO I am not seated very low in your vehicle. I have NEVER been in your vehicle. Why are you referring to a third party when YOU are certainly talking about yourself? Yourself is referenced buy the word I not YOU. Other non specific people are referenced by the word 'one' That applies to 'everyone' Notice the word is a combination of 'every' and 'one' It is clear you failed English and have a very minimal vocabulary. Stop saying YOUR when you are referring to yourself. Read more books to become fluent in the English language.
@@andrew_koala2974 sounds like you're incorrectly assuming your dialect is the only valid one There's over a billion English speakers there's always going to be variety
My favourite “wow, retroreflection is cool” moment happened a few months ago. I’m an emergency service volunteer and we were filming a training session so members could watch from home. My Sony A7S II kept turning its screen off, something it usually only does if I look through the viewfinder. After a few times having it turn back on randomly, I realised the proximity sensor used an infrared light reflecting off your face. With my uniform being covered with retroreflective tape, it kept detecting my uniform even though it was about a metre and a half away.
This is exactly why cameras should have manual overrides for virtually _every_ function. Manufacturers seem unable to anticipate every possible scenario of product use.
@@anhedonianepiphany5588 Most people wouldn't be able to understand all the manual options. I have a bit of trouble myself. Cameras should be more intuitive and easier to understand the options.
@@BY-bj6ic That's why they're overrides dumbass. If you don't understand what the option does, just leave it on auto! Why should users who need such features be denied them just because you don't understand?
Pbs is publicly funded by viewers. His videos are funded through his viewers as well through his patreon page. And thus his media continues to be amazing because many viewers agree with you about high quality of content enough to contribute..
@@doubtful_seer I prefer my content not to be push up in front of my eyes. I prefer to find it unfuling its beauty blooming along my strolled path on the way to find something related. Or as the answer neatly packaged for opening when the time is ripe. An answer to a question I place in the ethereal realm of satellites or through the terrestrial cables of good and evil hidden below our feet. I wonder if he has watched any of this channel yet? If not he (Hank from Sci sho) is truely missing out.
Yeah. The humor makes me stay and listen even if it's the topic I never knew I cared about. What I love is that the 'jokes' are spread so far apart it doesn't affect the educational aspect of the videos.
15:30 Actually in Austria and Italy, the red side faces you when you drive in the correct direction and the white side faces when you drive the wrong way. The logic behind this is that when you have other cars driving at night in a dark county road, you see red tail lights on the right side and white headlights on the left side of that road... So some genius decided to position these reflectors in a way they will always send you back the same colour of light a car would send you if that car would be driving on that lane. Even on very small and remote roads, the guard rails have reflectors coloured red on the right side and white on the left side facing the direction you are driving, copying the lights you see from the other cars. I was born in Brasil and lived there more than 20 years. After living only 5 years in Austria, it just feels soooo much more comfortable and intuitive this way, and now I can't help myself but to feel that the entire rest of the world has always had it all wrong.
@@crazoatmeal1854 Interstates didn't use them. They were used on regional highways, some urban streets. I go thru AZ occasionally now but I haven't seen any in a number of years. In the 60s and 70s they were fairly common.
Iowa Department of Transportation used this process on their Interstate highway speed limit signs in the early 1960s. I'm sure the revised 1970s vintage MUTCD compliance had something to do with requiring separate signs for Maximum, Minimum and Night speeds and elimination of a invisible reflective "night" speed limit text and its removal by the early 1970s. In fact, I have to think back quite a ways to remember "Night" specified speed limits. Regarding delineators embedded into the pavement: the story of "Bott's Dots," comes to mind for CalTrans. Despite attempts to offer such adhesive permanent delineators in other states, the climate does terrible things to them. They cannot, despite sloping designs, adhere to the surface with constant dramatic changes in cold and heat surface changes, over many seasons. Snow plows tear them away from the concrete and asphalt. The embedded markers are seen in southern states, some southwestern states and California. Glad you're doing a segment on this topic. Everybody has seen them, but know very little about them. Good job!
There are a few on I-35 north of Dallas.. It's a split sign white reflective with black lettering and black sign with white lettering. One for daytime speed one for night time speed
Retroreflectors are also used in Motion Capture when you see an actor wearing little balls, they're retroreflectors and the cameras have a ring of lights (often infrared) around the lens.
Oh wow, I always thought they were just there for being easy visual points to track. I mean, I'm sure some cheaper systems use that, but it's very interesting to hear they would use retroreflectors for that!
Never thought about it, but yeah, that prolly makes it much easier for the tracking software to follow the balls! Ive also seen mo cap suits with full stripes too tho.
And he shouldn't, for the simple reason that very little, if any, of this audience will ask for an apology. I myself would ask for one if there were no puns or dad jokes!
I’ve beecome so used to them from him I didn’t even notice. I had to go back and watch again to notice it. ... As a side note the pun in this comment was initially an accident do to me miss typing. But I left it as it is appropriate.
"No matter how good you think your headlights are..." Listen man, you haven't met some of the people driving in the opposite direction from me at night. Their headlights have millions of lumens that incinerate everything in their path for miles around.
Oh, just wait till you're a pedestrian and these jokers blind you without at least the minor shielding provided to your eyes by auto glass. Even some cyclists seem to have managed to get their hands on some excessive headlamps capable of dazzling passers-by. Based on this video, the cyclists should probably be relying more on retroreflective materials, anyway.
Those are the douchebags who put LEDs into a reflective headlight housing. LED headlights should only be used in projector housing, where they can be focused into a beam.
In Australia, we use red and white reflectors in the opposite way. Red is on your side of the road (left side here) to imitate the red lights from traffic in front. White is on the opposite side of the road (right side here), simulating the oncoming white headlights. And in-between, we use yellow to see the medium strip.
@John Irving "You have to be distracted to see them." Formulated that way your objection is NOT true. But obviously diverting your attention to READ them is distracting you from paying attention to the road, which means the PSA is kind of endangering traffic safety without wanting to.
John Irving I assume those same smart people built the ‘smart freeway’ with the glowing speed signs on every bridge, which my ADHD self gets her eyes glued to every time they come into view? 😑 Freeway too shiny. Not good. Change it back.
I drove around Scandinavia in the mid- 90s, and daytime headlights were mandatory (for car manufactures, anyways IDK about old or "classic" cars) Headlights were on, as soon as one turned the key. The studies showing that daytime lights saved lives had already been done, it was proven back then. So your idea would not only seem redundant there, but also a bit backwards. Why not put this responsibility on the manufacturers? The idea that anyone should have to put this reminder or advice up in 2020... I'd like to tell you it's clever, but it just makes me really angry.
technology connections is one channel that somehow pulls off reverse clickbait. I was not very interested in the video/topic when clicking in, but as the video progresses I get more and more interested.
@@ca-ke9493 For a similar vibe, Rick Beato's "Everything Music" YooToobs on 'what make this song great' is similar. He's player, producer, educator, and he loves music. You'll sit through college lever music theory class, most of will go right past you, and you'll love it because Rick digs the songs AND the theory.
16:10 the hexagon pattern is intended to separate the protective layer from the reflective structure. If the protective plastic was fused over the reflective, the lens effect would be vanished. If was no protective layer, the reflective structure would impregnate with dust.
That makes total and complete sense, and looking at some of those decals I have I can see it. Thanks. Hopefully Technology Connections sees this and pins your comment.
Here I was thinking that the hex pattern would be useful in making fishing lures. Marling baits would rock out that retroreflective tape and then some.
The first type of retroreflective films available had glass beads imbedded in a thin aluminum layer (“paint”) and covered by a transparent layer of acrylic. Since the difference in the indices of refraction of the acrylic and glass is less than the difference between glass and air, more scattering of light takes place and the retroreflective effect is less. To avoid this loss, the next generation of retroreflective films got rid of the acrylic coating in direct contact with the glass and so had a glass/air interface (less loss of light). To nonetheless protect the surface of the glass beads, a protective layer of polyester film was placed on spacers (the little hexagons) with air trapped in the pockets above the beads (as Vinicius stated). Best of both worlds: glass/air interface for best retroreflection and a smooth surface to avoid dust and dirt covering the glass beads. Btw. the problem with condensate on the surface of the film comes from the refraction of the light into many different directions by the little water droplets, thus canceling out the collimated retroreflection. In some cases this can be mitigated by placing a small roof over the sign to avoid cooling in the night air and thus minimizing condensate buildup. Source: I started my career in R&D for “tesalux” brand retroreflective films.
Addendum to my answer: a good overview of the different types of film and their manufacture can be found here: reflectivetape.info/articles/ . Cheers, Doc
This is the correct answer - I worked in TSSD for 3M, testing the retro-reflective films and conspicuity tape. The pattern shape itself is irrelevant to the tape's function, although hexagons are the simplest shape that tiles the plane with minimal boundary, and therefore maximizing the amount of retroreflective material. IIRC Avery mainly uses offset squares - and now overlapping circles (think scales), Reflexite mainly uses triangles, and 3M uses a sort of smushed diamond. The diamond and overlapping circles are close approximations to a minimal boundary tiling. I suspect the chosen patterns are for the purpose of brand recognition, as the hexagon patterns mostly came from chinese knockoffs and such (I could be wrong on that)
Retro reflection is also used in the simple "spy camera detectors" used to locate possible hidden camera lenses. They blink LEDs with an opening for your eye to look through on the center, so you can see almost 180 degrees and catch the retro reflection from a camera lens. This you can create a similar effect using a flashlight from next to your eye, and look for a tiny dot being reflected from someplace it shouldn't be (ceiling tile, book on s shelf, etc.) You still have to go check it out to be sure.
I can add another clarification, maybe: In the radio-altimeter of an airplane, they don't fire out a pulse and time the return. Instead, they emit a beam of continuously varying frequency, and then compare the outgoing frequency to the incoming (a much easier task, electronically speaking) to calculate the distance. I expect that the laser range-finder has some analogous trick...
@@fartingfury Just to be contrary ... I think all the early radar systems (pre WW2) were pulsed systems. Also, pulsed radar and sonar were, I believe, the only thing available at the low end of the market (small boat applications) for decades. It is probably only in the last 20 years that frequency modulation technology reached these inexpensive units. Don't these things, indicate that the pulse method is probably easier to implement?
@@andrewsnow7386 I wonder if early radar units could manage much by way of range-finding but otherwise you make a very good argument. I used to work in avionics, I wonder if there's a way I can find out for sure...
@@fartingfury First, I'm far from an expert in radar. It sounds like you have more experience than me. That said, here's what Wikipedia says about the early British "Chain Home" radar system: "Due to differences in reception patterns between stations, as well as differences in received signals from different directions even at a single station, the reported locations varied from the target's real location by a varying amount. The same target as reported from two different stations could appear in very different locations on the filter room's plot. It was the job of the filter room to recognize these were actually the same plot, and re-combine them into a single track." It sounds like the accuracy of this very early system was not great -- not too surprising. But, it's my understanding that by the middle of WW2, radar had revolutionized the determination of range finding for naval gun fire. Greatly increasing the likelihood of hitting the target ship. This would indicate fairly good range determination, as the ships would generally have been less than 100 feet (30 m) wide. However, I don't actually know that these these ship radars were a pulse type radar. I always assumed they were, but I really don't know. I tried to Google when frequency modulated radar was developed, but in a 1/2 hour of looking I didn't find anything that gave a date.
Percy Shaw invented the Cats Eye when looking at the eyes of a cat facing in his direction. If the cat had been facing the other direction, he would have invented the pencil sharpener.
I just wanted to say from a Materials Scientist, thank you for the shoutout in the end. It feels as though nobody knows about what we do or that we exist most of the time
@@Flumphinator I spent my entire career fixing problems so no one would even notice there was something wrong. No one ever says after a rainstorm, “Wow, my house didn’t flood.”
One of my favorite trivia is that the fading glow from the time bubble in Terminator 1&2, was achieved with retroreflective paint and an orange light on the camera that slowly dimmed throughout the scene.
Also used in at least one scene in another film to make it appear there was a light in the window in a cabin on the far side of a lake, they set a 3M panel in the window and hit it with a spotlight from the camera position. Not Enough light to add much illumination to the scene from that distance but the window really popped.
The honey-comb pattern on the reflective tape heat welds the protective top layer to the reflective underlayer. You need the layers to stay in close contact with each other to minimize the scattering of light that would increase if the layers were farther apart. It could be triangles or squares, but those would obscure even more of the reflected light. Another reminder of how amazing bees are 🐝👍🏽😀
I understand that bees do not actually build hexagons bit little tubes. Those then squish together to form hexagons. www.discovermagazine.com/planet-earth/scientists-explain-the-amazing-process-by-which-bees-make-hexagonal-honeycombs
@@robertwernecke2628 Bees use of hexagons was entirely accidental, based around their evolutionary needs; like all other evolved traits. Bees aren't amazing, evolution is; any species could've been the one to make that hexagon shape, and infact other animals do. The hexagon is not a feature of bees, its a feature of nature. Hexagons are the most efficiently packing shape, which uses the least amount of building material to fill the most space on a flat plane; so all animals which form small hive like structures are going to form hexagonal shapes; by virtue of evolution. Wasps produce hexagons by literally MEASURING with their antennae, a lot more similarly to people's construction through use of measurement, making what they do substantially more "intelligent" than what bees do. The perfect measurements of hexagons occurs the same no matter the species; bees produce Jewelers Hexagons and tightly build them one off of the other through molding the wax whilst wasps form slightly larger perfect Jewelers Hexagons through continually building intersections, inevitably leading to a perfect hexagon pattern. Either way, it was never bees. Honeybees are invasive, and damaging to native bee populations.
CGP Grey actually made an entire video ranting about how awesome hexagons are, and yeah it makes sense that they'd be used for that kind of application. Most efficient way to tile a plane with the least amount of lines!
"This is a cat." It doesn't get better than this! Now I know why I have been a Patreon supporter since the very beginning for Technology Connections! :)
I spent the whole video wonder: "When is he going to get to that 'Deflective' part?" Then, it dawned on me. Oh. He DEFLECTED the question. I feel smarter now.
Traffic engineer here. Just wanted to say thank you for the thoughtful and thorough explanation of retroreflectors and how we use them in traffic control devices (with a quick reference to platooning sprinkled in there).
@@LaMirah dude, just imagine a boomer and his/her mother using a tablet after the great grandchild painstakingly taught them how to "do the computer", like Jed and Granny Clampett. Dangit Daniel, wrinklies are funny and I'm poking fun at them. And I am one.
It also helps in waterproofing. In the old days, road direction signs in the Netherlands where blue backing with white retrereflective lettering on them, and over time the letter's edges got very jagged by water ingress (where the honeycombs were open). Nowadays, road signs are all retroreflective with a semitransparant blue backing over them, with cutouts where the letters go, with the added bonus that the blue colour of the sign stands out more, other than just seeing the letters float in mid-air.
@@IIVQ I work in a sign shop and yeah youre right they are phasing out the white reflective letters cause the high intensity just works better plus you can print on it and laminate it, further waterproofing
@@TommyWashow YOu know you have worked in a road sign shop when you have small dots of high-intensity reflective sheeting all over your clothing or coveralls.
HighlandSteam is correct on this, but it is not a "glue". The top layer will lose all its retroreflective properties if anything touches the microprism surfaces, be it water, dirt, oil or glue. During manufacturing, the top layer with the microprism coating (on its underside) is ultrasonically welded to a bottom layer that acts as structural reinforcement and a carrier for adhesives. The tiny hex shapes are the result of this welded hermetically sealed "pocket" between the adhesive back layer and the top film. (my career is converting these films for other uses beyond road safety)
"And of course, putting retroreflectors on those hazards themselves is also a great idea." Before this decade is out, this country should commit itself to painting EVERY DEER in retroreflective paint.
They've actually tried this on reindeer in Finland by painting their antlers. Didn't bother the animals, and made them incredibly visible to drivers. Only issue is that reindeer shed their antlers once a year. iirc, it was just an experiment, so idk if they'd ever actually implement it
In one of the early scenes you can spot eye shine from wolf spiders when illuminated by his phone. That would have been a fun thing to note in the context of this video. Wolf spiders have pretty brilliant green eye shine.
Former surveyor here. While you are absolutely right about one of the most common methods of taking surveying measurements (using light pulses bouncing back from retro reflectors), the tools you showed are different. The first was a level (or maybe a theodolite) and the next two were GPS receivers. Neither of those tools emit any light to take their measurements. Total Stations are the tool you were referencing: en.wikipedia.org/wiki/Total_station
Another Neat Use Case (idk if someone covered it in the comments already oof) is for 3D Scanning/Motion Capture. That is what those shiny ping pong ball looking things are, spheres covered with retroreflectors at known distances so the computer can do a bunch of trigonometry and stuff to know where the person’s limbs / robotic arm etc are. This is the “passive” method; some just use light up regular diffusive ping pong balls like Sony’s PSVR controllers
I drive something that can weigh up to 40 tons. I have no clue why people want to play around with it so much. Cutting me off, not me over, ECT. Fn nuts...
We have the reflectors on the moon to measure how far away the moon is, in case it ever tries to sneak up on us again. We're watching you, Moon, don't try anything stupid
Ah, explains the headline Google News served up to me yesterday. It was "September full moon arrives early". They must have caught it trying to sneak up on us.
@@Kalvinjj nonsense, we couldn't have put anything there. Most likely they're just measuring the distance to the TV studio where the moon landing was filmed. 😂
My mom got a bunch of retroreflective beads that were leftover from the engineering projects at her work, so I got to use them in some fun ways such as a fully retroreflective vest as part of a halloween costume so when a car came by I would glow super bright to the person in the car or to people with flashlights. It was hilarious.
One of my favorite things is being the only car on a freshly paved road at night, especially when all the reflectors are brand new. That velvety black, the stark, crisp white... There's nothing quite like it.
Add a little water or snow to the reflective painted lines and they disappear! It's always easier to drive at night when the road is dry. Those "cat's eyes" get filled with dirt and don't work either.
I'm Canadian and for many years we didn;t have cat eyes. snow plows and such would just scrape them off. 25 years ago I was in California for business. Rented a car and drove late night from San jose to Santa Cruz on Hwy 17. NEwly paved, new cat eyes. I felt like I was in a video game! Loved it and never forget it.
@@davidvoinier6008 What we call "cat's eyes" nowadays is a more modern device which uses the retroreflective surfaces, not the traditional ones with the two glass beads. The newer ones are far less prone to obscuring through dirt and grime, but can still be susceptible to other problems.
20:46 According to Wikipedia, with those retroreflectors, the lunar distance can be measured with an uncertainty Beyond Belief (tm) -- or about 1.1 millimeters.
what i always wondered about is, light travels at different speeds while passing through materials of different densities. so when measuring the distance to the moon, do they account for the density of the atmosphere? and if so, isn't the density different at different temperatures? i assume they use the travel time of the lasers to measure the distance.. because those reflectors on the moon must be too close to eachother to measure an angle right... right?
@@sliceofbread2611 There is some accounting for things like that, but it is imperfect at best. It is one of the number things that lead to the margin of error of about 1.1 mm.
@@sliceofbread2611 Yep. I was in a place where USSR did their experiment. I saw this big ruby laser, which was fired into the moon. USSR used a reflector on their moon rover for this purpose. And yep, they accounted for the density of the atmosphere. They did this experiment on their long-range communication station. This station can send and receive signals till the end of solar system and have a lot of sensors for temperature and atmosphere state.
@@abiosismlg613 i do not want to start a thread about this topic here, but most people i ask about this simply state that they did not go to the moon that early, and that they went there later.. can't wait for the moment people go there again and can confirm the landing modules actually being there.
@19:00 You mentioned how often retroreflectors are used on bikes and cars before. There'd be so much potential for a garage door to errantly think it was clear due to an obstruction that reflected the same light back.
Oh, good point! I should know this, my new bike's tyres have retroreflective strips. I wonder if that's why a barrier at the exit to a caravan site wouldn't work until I turned the bike sideways...
I find it pretty funny in the motorcycle handbook in my state it puts a lot of effort into telling you most people on the road is at all qualified to be on the road. But the people that write the books are the same people that let those people on the roads. And in the car driver's handbook it assumes people know how to drive but make mistakes.
@@philipc7273 Riding a motorcycle is significantly more dangerous. Walking is actually more dangerous than riding a bike (and riding a motorcycle for that matter) but all of them are more dangerous than a car.
@Johnny Thousand I think so too. There is a body of evidence about reflectors being camouflaged against other reflectors. In the working on the roadside safety course I did many years ago, this was explicitly explained, with pictures of people with a hi-vis jacket being barely visible standing in front of a police car. We have so many now. Adding borders, and distinctive breaks, helps to separate one from another.
The honeycomb pattern, and various other patterns printed on the front of prismatic sheeting, is there to identify the brand and quality of the sheeting. The manufactures provide samples for inspectors to compare with the signs the (always low bid, since the signs are owned by some part of government) contractor put up, so the inspector can determine that the signs meet the specification.
Moving to Colorado made me realize just how much I relied on the imbedded reflective markers. CO mostly doesn't use them because the snow plows would just rip them off of the road surface. I also found out that yarn with a thread of retroreflective fiber is a thing, and now I often crochet reflective stripes into beanies and scarfs.
I have been on roads that have ahallow grooves cut into the road surface for the reflectors to be mounted below the road surface and thus they are protected from the plows.
Thin retroreflective threads are everywhere. The guyline I bought for camping has a retroreflective thread wound through it. Anyone who's tripped over guylines wandering around the campsite at night time can appreciate anything that makes those bastards more visible.
The survey instruments shown here are an Automatic Level then 2 different GPS receivers. Neither use prisms (reflectors). The instrument that measures distances is called a Total Station. They are pretty cool and work in truly amazing ways.
As someone who drives professionally, I wondered why older road signs are easier on the eyes at night than new ones (but didn't care enough to find out). Now I know. Thank you!
Insufferable pedant alert: The angle of incidence/reflection is the angle between the light beam and _an imaginary line at 90° to the surface of the mirror,_ not between the beam and the mirror itself. Obviously it makes _absolutely no difference_ in practice, but it's a fun physics fact. You adopted a cat purely as a visual aid for this video. That's dedication!
It does make a difference with a curved mirror, for those you either have to use the conventional method (measuring from the normal line as you describe) or measure from an imaginary plane tangent to the curve.
Additional pedantry: the imaginary line is not so much a fact as a convention used to make teaching easier. It would make more sense to say the angle will be the same wrt the mirror when explaining flat mirrors, but would make the explanation for curved mirrors more complex where you would have to consider the plane tangent to the point of incidence. To keep the "definition" the same for all mirrors a line normal to the point of incidence is used. You were absolutely right when you said it doesn't matter which way you think of it, as long as you don't mix it up for yourself
When I was cycling to school my dad got me a reflective vest. Pretty much everyone who saw it commented something to the effect of "you can't be missed!" and after maybe 2 weeks of this I got fed up and started responding "Missing me is sorta the point of having it"
Before I was put on stand by, I would walk to work. After years of almost being run over by careless drivers I started wearing a traffic safety vest during the walk. My problems were reduced, but drivers are still careless idiots.
@@williamvergerwolf150 walking on the side of the road i often get drivers who drive closer and closer to when i am walking. like a homing missile. i dont know if they are purposefully targeting pedestrian or that they are accidentally driving crooked towards me.
@@Francois_Dupont I can't answer that, but it's normal to unconsciously steer in the direction you're looking if you're not careful. I guess this means they saw you and were watching, if only they'd realize they were getting too close..
@@williamvergerwolf150 this is what also think, but its still scary when they are coming at 100km/h and drive 2meter+ sideways from the original position.
"learn how it works, and how to use it properly" I wish I had teachers like you when I was a kid. They should have really driven home how dumb most people are. You do great work.
It's not so much that people are dumb per se, but the world is much more complex than the average person can handle. Even if you were educating yourself every day you'd still make stupid mistakes.
For about four months I would encounter some guy on the off ramp that had zero rear lights. No brake lights, no tail lights, not even a blinker. These encounters were at 11pm at night.
"Mirrors are great at reflecting!" Did you know that if you stick a piece of retroreflective tape on the bathroom mirror at night; shine a light on it; and say "Alec Watson" three times; his face will appear and make an appropriate pun.
16:04 The honeycomb structure is for fastening the upper part which contains the reflector to the lower part. There needs to be space between for the reflectors to work. You can choose virtually any structure but it needs to be a closed pattern - not for instance dots. Otherwise condensation and water vill creep inside the whole area and render it useless..-
Solas grade reflective tape has the honeycomb shape but the retro reflectors are formed into the same pattern not square behind. So the one in the video looks like a imitation of a regulated reflective tape.
When you're talking about light beams and curtains for safety, it always needs to fail safe. With emitter and reflector, you can get reflection from objects that pass between the emitter and reflector, which could cause the system to fail to recognize the obstruction. A beam style, with emitter and receiver, while it must be carefully aligned, is immune to these problems. If the beam is disrupted at all, the system will register it. This behavior is more desirable in a safety circuit like for overhead doors, and for automated processes that work with reflective material such as a conveyor counting boxes, and the tape on the boxes reflecting the beam (this does happen, I work in industrial automation, trust me).
I wonder how effective weeding out false positives by having the beam and reflector be specific colours and having a filter over the receiver would be?
Regarding trucks, you may have noticed that modern trucks have all their front lit by led lights. This makes the truck more visible, but also helps the truck driver see retro reflector signs
Right??!? Yet when I run them over a couple of times, suddenly I'm "at fault" because I was "on my phone" while "eating a steak" and "watching a movie". So unfair! Oh well, at least the jail cell is bigger than my truck sleeper, but the hookers are uglier
I think it has a lot to do with newer cars having always-lit dashes. We've got a 2018 Toyota and 2018 Nissan and I've noticed the only thing that tells you your lights are on is a small green indicator. The dash lights themselves are always on, unlike on all my older cars. So that might explain the ones driving like that around dusk. But after it's completely dark? No clue....
80% of the time, they are driving a Honda CR-V. I'm not sure what the design flaw is with them, but their drivers somehow turn off their automatic headlights.
I honestly had no idea. I thought those two things wandering around my house were alligators or something but it turns out they they are in fact cats too.
Fun fact! If you ever notice a random blue retroreflector on the road, look to your left or right and you’ll spot a fire hydrant! Fantastic video as always, Alec.
In Ireland they put green ones on the side of the road before junctions, so that if you're hunting for a side turn in the dark, you're more likely to see it in good time and navigate it safely.
Every single time you do a display of an item in that Dutch angle (or tilt) How It's Made style, I am flooded with good memories. I genuinely wonder how you get the slight pan so smooth and centered on the display the entire time. Great work as always :)
Re: signs too bright: THANK YOU! There’s a speed limit sign I pass every morning on my way to work that I think exists for one true purpose: to make me blind for the next 1/10th of a mile...
That bright sign is most likely made with 3M's Diamond grade Reflexite reflective film ,those are the new standard in many states such as Maryland which goes beyond the US DOT standards, they are bright,but more costly to purchase,about $150.00 a piece compared to the older industry standard, I got a STOP🛑 sign made with that in my room & it blows all the other STOP signs away in my neighborhood !,it lights up my entire room when the cell phone just emits a little light from the screen, I'll probably get a Yellow "No Outlet "sign made up with actual a 🚫🔌 on it as a joke ! Tired of people asking where the outlet is to charge their cellphones & devices 🤣
couple of those on my road, so stupidly blindingly reflective that you can't read the marks on the sign. More bureaucrats wasting tax money to make the world worse.
@@saadjamal1000 The linked part of the video was immediately preceded by the phrase "copycats appearing over the years." The "copycats" part was a joke since the part just before that was talking about technology that *copied* the way "cat" eyes work.
The cats eyes in the road get cleaned by driving over them, the weight of the car pushes the lenses down over a hard rubber that wipes the filth off. Which is a cool design feature! Also the signs on roadworks have extra light because the barriers get covered in road grime :)
Another great use of retro reflective tape is on pet collars and leashes. It gives my pup a lot of visibility, and me a 5 foot strip of visibility leading to the pup when I’m walking at night.
I was hoping it would be followed with "the magic of having two of them," because two cats appearing in a youtube video is magical (sometime dark magic, but still magical).
16:00 One time. I did it one time. The lanes markers WERE red. It was late at night and I had no idea why they were red. Then...a car came from the other direction. I immediately realized it was ME that was wrong but also that I WAS going the way I wanted to... But there were no lanes to my left...As it turns out though that was the way I wanted to go I had to backtrack to get on the right side becuase it was one of those split highways where North and South are actually seperated by a cliff in between them so you can't see the other. WHOOPS! Thanks! Now I'll never made that mistake again! So the red reflectors ACTUALLY MEANT SOMETHING? Wish they taught me stuff like THAT in driving school...
What's he saying? He says we are going the wrong way. How does he know where we're going? Yeah how does he know where we're going? Planes, Trains, and Automobiles.
A summary of state road regulations should be required reading but unfortunately most drivers ed now a days are "what is this sign" and "can you parallel park"
Another useful and under appreciated tip is on school busses in America have yellow reflective tape specifically around emergency exits and specifically show how far off the ground the inside floor of the bus is for when it may get into an accident
I'd imagine the reason you wouldn't want to use a retroreflector based system for a garage safety device is...well, you might have left your bike in the path of the garage door, or even just the retroreflectors on the rear headlights of your car that you parked a little too far back this time. It can only tell that it has an unobstructed view of A retroreflector, not necessarily ITS retroreflector :)
Usually the reason there's power to both of the sensors is that one is an emitter, the other is a sensor. If one was both the emitter and sensor, then any reflective surface could give a false positive. I've also seen these sensors confused if they're in direct sunlight; the door will start closing, and suddenly reverse when the door casts a shadow over the sensor; putting up a little sun-shade around the detector ensured it could only see the emitter.
@@georgf9279 how so? How does the laser tell the difference between the light hitting the retroreflector attached to the opposite side of the garriage and returning, Vs hitting the tail reflector of your car and similarly returning directly back to where it came from (it's what retroreflectors do after all). If you mean the general narrowness of the beam meaning less chance of hitting something reflective, perhaps true, but probably not something to be relied upon (if it fails ,that thing is in the worst place) Only thing I could think would be maybe some time of flight stuff, but that's gonna be complicated.
@@AngDavies My opinion: A laser would have not only a tight beam, but also, as pointed out in the video, would be able to be used to measure the distance from the emitter, retroreflector, and back to the sensor. If the chip in the garage door opener is fast/smart enough to know what the correct laser timing is, it could figure out the difference between the correct reflector and an incorrect reflector.
Interesting fact about the reflectors on the moon: Apparently they're getting dimmer. The most likely culprit is dust buildup. As the moon has no atmosphere for dust to float around in this was... unexpected. The most likely hypothesis is that the dust is being deposited from micrometeorite impacts, and that such impacts are much more common than anticipated.
Lunar dust is actually VERY electrostatically active, and objects can easily build up a charge with no atmosphere to dissipate it into, or to block the heavily ionized solar wind. Moon dust can actually get so electrostatically charged by solar wind that it "levitates"
@@xm1ch161 Your brain is filling in the caps from the previous information when you saw colors there. Basically your brain is doing the video compression to save processing time :D Notice that you can only see the colors when your eyes are not moving, otherwise visual data changes and you see the actual color of the image.
I love how unstructured the video appears and how I still learned a lot from what you said, even though at times it just seemed like continues rambling. Liked & Subscribed.
11:12 THANK YOU. It is incredibly scary seeing the amount of people driving around at night that have NO IDEA how their vehicle lighting works! The whole automatic headlights thing is great, if your vehicle has that option (both mine do) but there are so many different vehicles out there that purposefully seem to make it difficult to tell when your lights are actually on vs when they're in DRL mode. Around here, a lot of newer model Dodge Caravans always seem to be driving around with their lights off when seen from behind, and when I first noticed this and drove past one, I noticed their dashboard was fully lit up! WHY is it set up that way when these things don't have automatic headlights‽ It just proves how oblivious drivers really are and it's terrifying sometimes! The first thing I do when I get into a vehicle I'm unfamiliar with is figure out where all the switches and things are and what they do, so that I can prepare myself for properly operating the thing. But I guess that's due to too much common sense on my part, and expecting others to follow accordingly.
My late-model Subaru has illuminated gauges as well, but if the headlights are off it means the gauges are garishly bright. So, at night, if my gauges are practically blinding me, it’s a clue to turn on my headlights so that they dim to a reasonable level. Of course, during the day, the very bright gauge backlight is perfect to have. I wish more manufacturers adopted this standard.
My 20 year old Pontiac has automatic headlights. It's surprising that it's not standard across all cars when it was a thing on a relatively inexpensive model of car in the late 1990's.
@@rgiaco777 My dad's Nissan Altima attempted to utilize this trick, however, when you're driving in a well-lit area, or you begin driving during daylight hours and continue through sunset, it can take a frightfully long time for that "garishly bright" lighting to begin to be uncomfortable and hint to you that maybe your headlights are off when they should be on. I personally always preferred to have an unlit dash during the day, which is designed in such a way that the instrument cluster can be well-lit by ambient light (i.e.: don't sink the gauges halfway down to the engine block). I've also become annoyed at having automatic headlights, as with my late Toyota Corolla. In that case, I am unable to signal oncoming drivers that THEIR headlights are off by turning my lights off and on again repeatedly. Because my headlights are automatic, it prevents me from turning them off when there is insufficient ambient light, thus prevents me from issuing the "your lights are off!!" signal.
Some manufactures have implemented measures to alert drivers to you turn on their headlights when it is needed. VW used to turn off their gauge lights at night if the headlights weren’t on. I had a 06 Pontiac Grand Prix that would alert me that headlights were suggested when it was dark enough and the switch was in marker mode or off. My work had a 09 Silverado that would turn off the gauge lights at night when the auto headlamp system was disabled.
I love this channel and how Alex brings curiosity, science and great commentary to light (especially in this segment). Some of our National Parks employ a few of these retroreflective markers near some of their wilderness trails. Ask me how I know? One beautiful November day, we went on a lovely hike in Arches National Park through a region aptly named “Devil’s Garden.” Having begun in the afternoon, as the sun got lower we knew we should probably turn back. But there was just one more magnificent arch we had to see. We were equipped with day pack, jackets, headlamps, paper and preloaded GPS trail maps on our smart phones, snacks, and water. So, of course, it did get very dark very quickly. We were able to retrace our steps back to a familiar, large well-marked trail sign at an important fork. It was only a few miles more to the parking lot. But then, not thirty feet past the sign, we lost the trail. We could clearly see trails leading to places other than the parking lot. But, no trail leading home. We were at a convergence of at least 6 rock structures known as fins, the very structures that make the arches. They are harder rock left standing as erosion removes soil and softer rock from the valley. Some of these fins arise several hundred feet above the valley floor. Some start out as broad paths, but the area is aptly named because after ascending twenty meters or so above the valley, they just peter out to a sheer drop! Good thing we had our headlights! We must have gone up and down, back to the big sign a dozen times. GPS said we were spot-on the trail, but every direction from the sign we took led to danger and disaster. Then, looking down a broad and sandy wash that looked nothing like a trail, my headlight picked up one of those retroreflectors about 250 meters away, nestled among some shrubs. A trail marker? Were we saved? Let’s find out! Down I scrambled to the marker. As I got close enough, I could read a message. It said, “Not a trail. Danger!” Behind the marker was thick scrub and an increasingly steep descent down to what I then suspected might well be hell. The retroreflector to the gates of hell! Well, alrighty, then. All that for nothing. Huff and puff back up the hill to the big sign one more time. I thought we might just have to spend a very chilly night in Devils Garden, knowing in the morning, hundreds of park visitors would flood the trail. Wait a minute. Why not throw up a prayer? It couldn’t hurt. So, after asking for a “sign”, I passed a scrub pine tree at the base of a steep rock not far from the big sign. I had seen it several times that night. But this time my light caught an important detail. Some of the bark of the tree was smooth and white, well worn, as if thousands of hands had grasped the tree to get a purchase onto that steep rock at its base. It was a sign from heaven in Devil’s Garden. That steep rock was the foot of the fin we needed to take to get back on trail. I sure would have appreciated a retroreflector arrow at that tree trunk pointing the way home, or even a neat stack of rocks. Nevertheless, in no time we were at the parking lot, where our lone car was still waiting for our return.
His appearance says 1960's bully, while his words say nerd. His studio says late 90's TV show, his jokes say biology teacher. His outro music says 1980's instructional video, his cat says nothing. Alec you're all over the place. Just as you should be.
Most accurate description of this channel :D
I discovered this channel recently and I can relate to that, to add a thing his face says Eraserhead.
The diversity we need
He reminds me of the guy from 60 minutes who would go on long rants about certain products.
@@scrubplays1863 John Stossel?
Ex truck driver here. I've never had issues reading signs at night, unless it had fine print. For example, while driving in New Jersey, I saw a sign that read, "Garden State Parkway," but I didn't see the tiny writing on the bottom of the sign that read, "no vehicles over 5t GVW." That didn't end well...
Truck driver here. Yeah I never understood why they would use fine print. I've also seen some that have more words than a harry potter book on just one sign. How am I suppose to read that when the speed limit is 70. Another one I have a problem with is when they put bright flashers on the sign. Can't read it til you're about to pass it. Luckily most of the time you can guess what it means based on the shape. I now just run in the Texhoma region so the first few times I slowed down a bit and was careful but now I've memorized them
@@Gamerdude753 I know right? Whoever designed these signs needs to try to read them at speed.
"US 209 Closed to commercial traffic beyond exit..." zoom!
"Wait, beyond exit what?!"
@@Trainfan1055Janathan A pet peeve of mine is also when they require proper understanding of the local language. For example here in Austria there are occasionally 30km/h speed limit signs in villages with „Gilt nur für Heizöltransporte“ (“only applies to fuel oil transports”) below. Even if you know a bit of German it’s unlikely you’ll know that word.
@@Mike-oz4cv For a long two seconds I wondered why there are German signs in Australia. Finally it happened to me too.
@Michael K That's how I got two tickets in two mornings in a row in Belgium. A sign in only Flanders and no symbol of any kind that made a local street conditionally one-way.
"This is a cat."
I really appreciate the visual aids on this channel.
A CAT? In an Internet video? How unexpected!!
yes, i was so relieved when we were told for certain it is a Cat. i wasn't sure if it was a Gorilla and that made me uneasy.
Absolutely necesary :)
Gotta love the cat! :)
@Paul Weaver
that would've been great too.
My fiancée is a truck driver (18-wheeler,) and we are currently driving at night. So excited to hear you ask what we see from a truck cab! The reflections look just as bright to both of us as they do from a car. We love your channel!
I wonder if that's why some signs are so high up to accomodate truckers as well as passenger cars.
Congratulations by the way!
i dont think thats how it works...@@frankharr9466
How's the weather high up in the Cab. It must be hard seeing through all the clouds.
Just found this channel and this comment was clutch
Came to the comments just for this, thanks for the input!
Truckers can see the reflectors just as well. They "fade" sooner though, but it's not an issue since they've served their purpose at that point. (Source - me: trucker for 6 years)
Fun fact - a lot of road paint also has glass beads in it in order to create a reflective surface. (Source - me: road painter for...about a month) (edit... Oh... You covered that...I commented too soon. I should have known you'd cover that... Ok :)
Near my house they were painting last month and after throw some paint they covered it with a clear sand. After some asking the clear sand its in fact glass beads.
@@mauriciomarianocarneiro when I was doing it, our sprayers had a reservoir for the beads. It would drop those as it was spraying. Most of the time we would also have to do exactly as you just said because it would sometimes clog up, and it would almost always run out of beads before paint.
I used to live next to a place where those big green interstate signs were made. They probably did other stuff too but those glass beads were always on the ground outside it.
YOU'RE WINNER!
(anyone who gets this is a nerd)
Confirmed, also 6 year truck driver lol.
It's quite a sight from the cab of a fire engine heading to an emergency at 3 in the morning when no one else is on the road. Every road sign, mile marker, mailbox reflector and driveway marker reflects your emergency lights right back at you and makes the world look like a giant red-themed disco club.
So a Disco Inferno then ? I'll see myself out .
@@hughgrection7246 that was perfect
For sure, especially with led lights. It's pretty disorienting really.
One of the things I appreciate but sometimes fail to remember is the standard reflective house number signs installed by the roads and safety departments.. especially helpful in heavy drifts of snow (making low signs irrelevant) kind of a similar concept to a housing addition I lived in, the curbs were concave (inward?) and near the driveway, sometimes under the mailboxes, the house number was painted reflective on black in the curb.
I remember the first time driving red and blues at night. Really had to pay attention and not look at those frantically flashing signs.
love that there's a VHS tape holding up the mirror.. making it a retro reflector
Thanks for the snorting laughter!
Oh my God, I hate myself for not figuring that out on my own. That's punny!
(though in my defense, I was thoroughly distracted with the r/cursedimage in the mirror to think about puns at that point)
That was a beta tape
@@wardsdotnet So ... it's even more retro is what you're saying?
AAAGH that face!!
Can we all just take a moment to appreciate the dedication it took for him to hold that face the entire time the mirror was panning across? He made damn sure that gag landed.
That was a photo in the mirror.
@@OrchardcottagefarmCo 3 months late but his head is shaking and his tongue moves a bit.
Ikr
@@theus83His face was shaking when he took that photo, resulting in a shaky tongue.
@@MarioGoatsephotos don't move
I’m cracking up at the slow pan with his face reflected on the mirror. Give this man a prime time show on discovery or something
ikr this guy has exactly my sense of humor
No! Please don't. Then every episode will take at least 3 times as long as after every commercial break, they will tell you about 1/3rd of what they told you before the commercials because they think the viewers are stupid.
@@weeardguy MAY I recommend some nice
science-channel to you? Just because, well, the learning never ends, duh?
@@loturzelrestaurant Well you may ;) But I hardly have the time to watch it next to all the others like Tom Scott, ElectroBOOM, Bigclive and Technology Connections ;)
@@weeardguy Tom Scott is great BUT have you heard of Sci Man Dan?
Oversimplified?
Bluejay?
Illuminaughtii?
Hbomberguy?!
CGP Grey?
"This is a cat" remains my favorite subverted expectation joke on this website of all time solely because of how elegantly it fits into the video
I did literally laugh out loud at that. Brilliant edit.
I have rewatched this video just for that line! And that lovely cat.
13:29
@@pratherat please explain
@@pratherat i had to watch it 7 times to get it...
I drive a truck, despite the headlights being 6' lower than my eyes, retroreflectors work very well and I am very grateful they are a thing. Especially cats eyes.
Thanks for the videos
I'm glad somebody took the time to answer this question!
Came here specifically looking for this reply, thank you for sharing!
Another truck driver here and I concur with the above comment.
thank you
Thanks for answering. Once he mentioned it, it became one of those questions that I never knew I desperately needed the answer to!
The "wrong way" lane reflectors (potentially) saved my life once! I moved to a new city with much bigger and wider roads with a lot more lanes on each side than I was used to. One time I was driving at night and I went through a huge intersection with multiple entrances and exits to the highway and I went down the wrong direction - fortunately there was almost no one else around anyway because it was late, but I realized my mistake almost immediately because suddenly the whole road was covered in red light.
My problem is I'd see all the red cyberpunk-looking lights and think "Hey, this road looks _really cool!"_
I still say retro reflective tape is best used to put eye shaped cutouts high in trees overhanging roads and bicycle trails in sketchy, poorly lit areas.
Hahahaha building our new house on a wooded lot with a fairly long driveway…new plan activated. 😂
ROFLMAO!
Aargh, no. Not anywhere where there might be an actual wild animal to brake for.
This is the kind of graffitti we need
@@dzymslizzy3641Thanks for grabbing your keyboard before rolling
In my job as a paint chemist I formulated retroreflective paint for use on railcars. The tiny glass beads used in the paint had a weird property: they were extremely slippery. A small amount spilled on the lab floor turned it into an ice skating rink.
Much worse than an Ice Skating Rink.
When one happened to fall on a floor of these tiny tiny glass beads
it could be described a 'poetry in motion' given the poetic words that
were called out after a painful landing.
Silica gel beads do much the same on linoleum. They also bounce in a way that's very satisfying if you're bored and working late in a discount retail store as your first job in high school.
Allegedly.
@@j_taylor LOL.
Same thing with the polymer beads used in water softeners.
I did a small stint of road painting one season and it will make everything slippery regardless of the surface and a lab floor sounds like a nightmare... Ohh and a small PSA for anyone who wants to use the stuff you want to wear goggles/glasses or some face covering so you do not get it into your eyes. I mean this sincerely because it's not like sand these little bastards will roll around your eyes for days and water only helps so much.
"Drivers are idiots"
Can confirm. Have driven, am idiot.
Same
@@gtbkts Same
Same
hahaha i concur also am idiot.
Guess that means I'm not an idiot. Will be soon.
The reason they often don't use a retro reflector on garage doors is because, like you also mentioned in your video, cars also have these reflectors, so they might cause false signals for the sensor. I have had this as an driver of a first responder vehicle wich had retro reflective striping. The sensor registered it's signal bouncing of from the striping and the garage door closed on top of my ambulance. They quickly converted the system to the set-up with the LED and the receiver on seperate ends.
Yep.... early ones definitely used a simple reflector system, and you have explained perfectly why it was discontinued.
Ah, does make sense. But then: It would be easy to put the retro reflector at the end of a small black tube or shielding, so the angle it reflects back is limited to wherever the open end points to. Makes alignment much easier and tolerant.
Same problem in automation, where the retroreflective garments of the staff can interfere with the optical sensors in the production line.
@@JouMxyzptlkThe issue isn’t the reflector the sensor is supposed to see, it’s all the reflective things that the sensor isn’t supposed to see. For example, the reflective logos on someone’s running shoes could be misinterpreted as “all clear” as the garage door closes on their foot.
@@JouMxyzptlk also shouldn't be too difficult to have a "calibration" button that would save the strength of the returned signal and not accept stronger signals (edit: ie. you put your system in place, press "calibrate", and it no longer accepts stronger signals until "calibrate" is pressed again)
A few decades ago, my family went on vacation to England. The road sign “cats eyes removed“ was one of the more unsettling road signs we’ve ever seen, but it’s nice to know that there’s a reasonable explanation!
I'm an orribile person for laughing at that for 10 minutes 😅😂
Try learning they're called cats eyes when you're 7 years old. That's unsettling too, because it's pretty obvious cars drive over them. Getting used to that and other things is why I laughed almost as much as @@Valery0p5! XD
In the late 90's with the dawn of the digital photography age... and as advancements in ink came along anyway... There was a very fine tipped felt marker that showed up in Walmart's "craft" section, called "Pet Eye Remover"... AND probably the same product was released somewhere else as a "Red-Eye Remover" for photographs...
My little brother picked one of them up and asked almost instantly "What's a pet eye remover for?" AND before my mother could have a CHANCE to think, I felt inspiration hit, and threw myself into vibrant demonstration...
"Come 'ere ya' little bastard!" I scooped up an imaginary small animal and proceeded to stab violently and make a sickening squishy-pop sound (as kids are prone to do)...
Now, here's where I explain that the ENTIRE FAMILY were members of the local Humane Society... AND we had been active for over a decade by that point, even part-timing as volunteers for animal control, to make house calls, whether for picking up strays or investigating (at least as preliminary) for abuse allegations... or just to help out pet owners who were having trouble... SO we'd all been around a bend or two, and there was a somewhat callous edge to all our humor as we've all "seen some sh*t" along the way...
BUT the several elderly ladies and a couple employees of the store did NOT know that part of the story. They just saw and overheard my dubious "conversation" with my little brother, and our mother CRACKING UP at the antics, even while (of course) my brother shot a look sort of like a whipped puppy for a moment and protested "NO!" Of course, that was before he thought better of himself and realized "Yeah, once again your older brother is pulling your chain..."
At any rate, as we carried on down the aisle, having returned the "Pet Eye Remover" pen to the little bin on the shelf, there was a near-stampede over to examine this ghastly invention and probably an inquisition of the poor employees as to WHY THE F*** would Wally World even stock such a HORRIFIC device...
Maybe not, but we were back within a month and there were NO MORE "Pet Eye Removers"... SO I can quietly enjoy the tiny satisfaction that maybe I did "get at" Walmart... I don't know. ;o)
@@gnarthdarkanen7464 Hahahahahahaha! Great story! XD Thanks for sharing it :)
@@eekee6034 Always welcome!!! I'm just glad you enjoyed it as much as I did "living it"!!! ;o)
It just occurred to me, this video explains why signs are BLINDINGLY bright when I'm driving my Miata at night. First of all, you are seated VERY low in the vehicle. Your head is at door handle level compared to most other vehicles. Secondly, the car has headlights which pop-up into a position that is almost the same height as your eyes while seated in the vehicle.
Meaning, this is one of the few cars where your eyes and your headlights are very close to the same position, making the signs appear brighter for longer than basically any other vehicle I've driven. Now I know why. Thanks for the education.
NO I am not seated very low in your vehicle.
I have NEVER been in your vehicle.
Why are you referring to a third party when YOU are certainly talking about yourself?
Yourself is referenced buy the word I not YOU.
Other non specific people are referenced by the word 'one'
That applies to 'everyone' Notice the word is a combination of 'every' and 'one'
It is clear you failed English and have a very minimal vocabulary.
Stop saying YOUR when you are referring to yourself.
Read more books to become fluent in the English language.
@@andrew_koala2974 your comment is so unnecessary
@@andrew_koala2974 uh-oh! Weee-wooo the Grammer police just showed up
@@andrew_koala2974 sounds like you're incorrectly assuming your dialect is the only valid one
There's over a billion English speakers there's always going to be variety
@@andrew_koala2974 He just said it that way to piss you off. Mission accomplished.
My favourite “wow, retroreflection is cool” moment happened a few months ago. I’m an emergency service volunteer and we were filming a training session so members could watch from home. My Sony A7S II kept turning its screen off, something it usually only does if I look through the viewfinder. After a few times having it turn back on randomly, I realised the proximity sensor used an infrared light reflecting off your face. With my uniform being covered with retroreflective tape, it kept detecting my uniform even though it was about a metre and a half away.
This is exactly why cameras should have manual overrides for virtually _every_ function. Manufacturers seem unable to anticipate every possible scenario of product use.
that was an awesome tale, good sir
@@anhedonianepiphany5588 Most people wouldn't be able to understand all the manual options. I have a bit of trouble myself. Cameras should be more intuitive and easier to understand the options.
@@BY-bj6ic That's why they're overrides dumbass. If you don't understand what the option does, just leave it on auto! Why should users who need such features be denied them just because you don't understand?
Around 0:40 you can see pinpoints of light on the ground. These are likely insect eyes and spider eyes which also act like retroreflectors.
In person, the light reflected from most insect and spiders eyes is pale lavender!
@@o.m.p.h.4483and a very metallic green color.
@@o.m.p.h.4483 in australia, crocodiles also shine like this at night and it is indeed a great reminder to never swim in croc country
I think that's just dew on the ground
This dude needs funding from PBS. These pieces of esoteric knowledge are great fun to watch.
He already uses PBS style music! I'm not complaining, I love it.
Pbs is publicly funded by viewers. His videos are funded through his viewers as well through his patreon page. And thus his media continues to be amazing because many viewers agree with you about high quality of content enough to contribute..
I don’t think he works on sci show anymore, but I bet hank green could help really push this content in front of more eyes.
@@doubtful_seer I prefer my content not to be push up in front of my eyes. I prefer to find it unfuling its beauty blooming along my strolled path on the way to find something related. Or as the answer neatly packaged for opening when the time is ripe. An answer to a question I place in the ethereal realm of satellites or through the terrestrial cables of good and evil hidden below our feet. I wonder if he has watched any of this channel yet? If not he (Hank from Sci sho) is truely missing out.
His voice is aesthetically pleasing as well
That pan over the mirror was everything I could have hoped for.
That pan over the mirror was everything I fear.
Loved it lmao
I laughed so hard, I had to go back and watch it again to hear what he said.
Hahaha yes I loved it too!
Alec can pull some AMAZING faces
The not so subtle, subtle humor of this channel makes me laugh more than I probably should
Yeah. The humor makes me stay and listen even if it's the topic I never knew I cared about. What I love is that the 'jokes' are spread so far apart it doesn't affect the educational aspect of the videos.
agreed I love this channel so much
That’s because you’re a NERD.
And you’re in good company. (Fellow nerd here)
“Remember science? The process? Ah. Good times.”
Saying the word "science" doesn't magically make one right. Only stupid people fall for this "political" trick
15:30 Actually in Austria and Italy, the red side faces you when you drive in the correct direction and the white side faces when you drive the wrong way. The logic behind this is that when you have other cars driving at night in a dark county road, you see red tail lights on the right side and white headlights on the left side of that road... So some genius decided to position these reflectors in a way they will always send you back the same colour of light a car would send you if that car would be driving on that lane.
Even on very small and remote roads, the guard rails have reflectors coloured red on the right side and white on the left side facing the direction you are driving, copying the lights you see from the other cars.
I was born in Brasil and lived there more than 20 years. After living only 5 years in Austria, it just feels soooo much more comfortable and intuitive this way, and now I can't help myself but to feel that the entire rest of the world has always had it all wrong.
This is quite amazing and informative
That actually does make a lot of sense.
Wouldn't that make the road markings and car lights too similar to each other ? At a distance/glance ?
Or is it not a problem ?
Urgent call for international standards. Please.
Younes Layachi car taillights are brighter than the only reflected lights...
Also, one set moves and the other set doesn’t. 😂
“MA! that weird guy with the tweed is back! He’s just standing in the road talking to himself”
"He looks like Grandma, the fucking thing!"
I thought it was hounds tooth.
@@syd.a.m I was hoping you'd be here.
"What's he going on about?"
In the DARK Too!
I remember in Arizona some highway speed limit signs showed a daytime limit and a nighttime limit. Only the night sign was reflective.
Texas too. Though I don't remember that from passing through Arizona.
@@crazoatmeal1854
Interstates didn't use them. They were used on regional highways, some urban streets. I go thru AZ occasionally now but I haven't seen any in a number of years. In the 60s and 70s they were fairly common.
Iowa Department of Transportation used this process on their Interstate highway speed limit signs in the early 1960s. I'm sure the revised 1970s vintage MUTCD compliance had something to do with requiring separate signs for Maximum, Minimum and Night speeds and elimination of a invisible reflective "night" speed limit text and its removal by the early 1970s. In fact, I have to think back quite a ways to remember "Night" specified speed limits. Regarding delineators embedded into the pavement: the story of "Bott's Dots," comes to mind for CalTrans. Despite attempts to offer such adhesive permanent delineators in other states, the climate does terrible things to them. They cannot, despite sloping designs, adhere to the surface with constant dramatic changes in cold and heat surface changes, over many seasons. Snow plows tear them away from the concrete and asphalt. The embedded markers are seen in southern states, some southwestern states and California. Glad you're doing a segment on this topic. Everybody has seen them, but know very little about them. Good job!
James S. They still are
There are a few on I-35 north of Dallas..
It's a split sign white reflective with black lettering and black sign with white lettering. One for daytime speed one for night time speed
The sentence "This is a cat." made me laugh way harder than it should.
Retroreflectors are also used in Motion Capture when you see an actor wearing little balls, they're retroreflectors and the cameras have a ring of lights (often infrared) around the lens.
Jeremy Lang This is a very nice fact. Thank you.
Oh wow, I always thought they were just there for being easy visual points to track. I mean, I'm sure some cheaper systems use that, but it's very interesting to hear they would use retroreflectors for that!
i didn't know that!
Never thought about it, but yeah, that prolly makes it much easier for the tracking software to follow the balls! Ive also seen mo cap suits with full stripes too tho.
Is that right? I thought those were, like, sensors of some kind. though now that I'm saying that out loud, of course they fucking aren't.
I love how much more aggressive he's getting with the puns. "No, I won't apologize."
And he shouldn't, for the simple reason that very little, if any, of this audience will ask for an apology. I myself would ask for one if there were no puns or dad jokes!
Crnobog I fully agree! “... are G bee’s knee’s.” Is still ringing in my head haha
Never apologize for awesomeness.
I’ve beecome so used to them from him I didn’t even notice. I had to go back and watch again to notice it.
...
As a side note the pun in this comment was initially an accident do to me miss typing. But I left it as it is appropriate.
"No matter how good you think your headlights are..."
Listen man, you haven't met some of the people driving in the opposite direction from me at night. Their headlights have millions of lumens that incinerate everything in their path for miles around.
Or the guy who drives behind me.
Oh, just wait till you're a pedestrian and these jokers blind you without at least the minor shielding provided to your eyes by auto glass.
Even some cyclists seem to have managed to get their hands on some excessive headlamps capable of dazzling passers-by. Based on this video, the cyclists should probably be relying more on retroreflective materials, anyway.
Now I'm waiting for StyroPyro to want to "improve" upon fancy "laser" headlight systems in some Euro makes. I better make sure he has considered this.
Those are the douchebags who put LEDs into a reflective headlight housing. LED headlights should only be used in projector housing, where they can be focused into a beam.
And as for cyclists with really irradiating flashing lights. I've a good mind to have an epileptic fit and loose control just to spite them. :-)
In Australia, we use red and white reflectors in the opposite way. Red is on your side of the road (left side here) to imitate the red lights from traffic in front. White is on the opposite side of the road (right side here), simulating the oncoming white headlights. And in-between, we use yellow to see the medium strip.
Idea: Sign that says "headlights save lives" in electrically lit letters. Below, a row saying "thank you" in retroreflective letters.
@John Irving "You have to be distracted to see them."
Formulated that way your objection is NOT true. But obviously diverting your attention to READ them is distracting you from paying attention to the road, which means the PSA is kind of endangering traffic safety without wanting to.
@@Ugly_German_Truths Yep, its completely retarded.... and dont get me started on the bullshit led billboards near roadways too.
@@Fanta.... Are you talking advertising boards or useful signs? I think the former... but... they don't exist here in the UK to my knowledge
John Irving I assume those same smart people built the ‘smart freeway’ with the glowing speed signs on every bridge, which my ADHD self gets her eyes glued to every time they come into view? 😑
Freeway too shiny. Not good. Change it back.
I drove around Scandinavia in the mid- 90s, and daytime headlights were mandatory (for car manufactures, anyways IDK about old or "classic" cars) Headlights were on, as soon as one turned the key. The studies showing that daytime lights saved lives had already been done, it was proven back then. So your idea would not only seem redundant there, but also a bit backwards. Why not put this responsibility on the manufacturers? The idea that anyone should have to put this reminder or advice up in 2020... I'd like to tell you it's clever, but it just makes me really angry.
Sees the title: "I'm not interested in that."
Sees who uploaded it: "K I'm going in."
Exactly my same thought process.
technology connections is one channel that somehow pulls off reverse clickbait. I was not very interested in the video/topic when clicking in, but as the video progresses I get more and more interested.
Same here. And as expected the video fully held my attention.
Indeed
@@ca-ke9493 For a similar vibe, Rick Beato's "Everything Music" YooToobs on 'what make this song great' is similar. He's player, producer, educator, and he loves music. You'll sit through college lever music theory class, most of will go right past you, and you'll love it because Rick digs the songs AND the theory.
16:10 the hexagon pattern is intended to separate the protective layer from the reflective structure. If the protective plastic was fused over the reflective, the lens effect would be vanished. If was no protective layer, the reflective structure would impregnate with dust.
That makes total and complete sense, and looking at some of those decals I have I can see it. Thanks. Hopefully Technology Connections sees this and pins your comment.
Here I was thinking that the hex pattern would be useful in making fishing lures. Marling baits would rock out that retroreflective tape and then some.
The first type of retroreflective films available had glass beads imbedded in a thin aluminum layer (“paint”) and covered by a transparent layer of acrylic. Since the difference in the indices of refraction of the acrylic and glass is less than the difference between glass and air, more scattering of light takes place and the retroreflective effect is less.
To avoid this loss, the next generation of retroreflective films got rid of the acrylic coating in direct contact with the glass and so had a glass/air interface (less loss of light). To nonetheless protect the surface of the glass beads, a protective layer of polyester film was placed on spacers (the little hexagons) with air trapped in the pockets above the beads (as Vinicius stated). Best of both worlds: glass/air interface for best retroreflection and a smooth surface to avoid dust and dirt covering the glass beads.
Btw. the problem with condensate on the surface of the film comes from the refraction of the light into many different directions by the little water droplets, thus canceling out the collimated retroreflection. In some cases this can be mitigated by placing a small roof over the sign to avoid cooling in the night air and thus minimizing condensate buildup.
Source: I started my career in R&D for “tesalux” brand retroreflective films.
Addendum to my answer: a good overview of the different types of film and their manufacture can be found here: reflectivetape.info/articles/ . Cheers, Doc
This is the correct answer - I worked in TSSD for 3M, testing the retro-reflective films and conspicuity tape. The pattern shape itself is irrelevant to the tape's function, although hexagons are the simplest shape that tiles the plane with minimal boundary, and therefore maximizing the amount of retroreflective material.
IIRC Avery mainly uses offset squares - and now overlapping circles (think scales), Reflexite mainly uses triangles, and 3M uses a sort of smushed diamond. The diamond and overlapping circles are close approximations to a minimal boundary tiling.
I suspect the chosen patterns are for the purpose of brand recognition, as the hexagon patterns mostly came from chinese knockoffs and such (I could be wrong on that)
Retro reflection is also used in the simple "spy camera detectors" used to locate possible hidden camera lenses.
They blink LEDs with an opening for your eye to look through on the center, so you can see almost 180 degrees and catch the retro reflection from a camera lens.
This you can create a similar effect using a flashlight from next to your eye, and look for a tiny dot being reflected from someplace it shouldn't be (ceiling tile, book on s shelf, etc.) You still have to go check it out to be sure.
Land surveyor here:
None of the videos of surveyors you used were using reflectors (except for their vests). All of them were using GPS units.
I can add another clarification, maybe: In the radio-altimeter of an airplane, they don't fire out a pulse and time the return. Instead, they emit a beam of continuously varying frequency, and then compare the outgoing frequency to the incoming (a much easier task, electronically speaking) to calculate the distance.
I expect that the laser range-finder has some analogous trick...
@@fartingfury Just to be contrary ... I think all the early radar systems (pre WW2) were pulsed systems. Also, pulsed radar and sonar were, I believe, the only thing available at the low end of the market (small boat applications) for decades. It is probably only in the last 20 years that frequency modulation technology reached these inexpensive units. Don't these things, indicate that the pulse method is probably easier to implement?
@@andrewsnow7386 I wonder if early radar units could manage much by way of range-finding but otherwise you make a very good argument. I used to work in avionics, I wonder if there's a way I can find out for sure...
@@fartingfury First, I'm far from an expert in radar. It sounds like you have more experience than me. That said, here's what Wikipedia says about the early British "Chain Home" radar system: "Due to differences in reception patterns between stations, as well as differences in received signals from different directions even at a single station, the reported locations varied from the target's real location by a varying amount. The same target as reported from two different stations could appear in very different locations on the filter room's plot. It was the job of the filter room to recognize these were actually the same plot, and re-combine them into a single track."
It sounds like the accuracy of this very early system was not great -- not too surprising.
But, it's my understanding that by the middle of WW2, radar had revolutionized the determination of range finding for naval gun fire. Greatly increasing the likelihood of hitting the target ship. This would indicate fairly good range determination, as the ships would generally have been less than 100 feet (30 m) wide. However, I don't actually know that these these ship radars were a pulse type radar. I always assumed they were, but I really don't know. I tried to Google when frequency modulated radar was developed, but in a 1/2 hour of looking I didn't find anything that gave a date.
I suspected as much, but stock footage can only be so specific...
Percy Shaw invented the Cats Eye when looking at the eyes of a cat facing in his direction. If the cat had been facing the other direction, he would have invented the pencil sharpener.
Lmao
Underrated
WAIT NOOOOOOO
HAHAHA
Or the tea towel holder.
I just wanted to say from a Materials Scientist, thank you for the shoutout in the end. It feels as though nobody knows about what we do or that we exist most of the time
A lot of fields are like that
I do, and I appreciate you all.
That's because material science is the foundation of how things work, and most people don't know jack about how things work
“If you do something right, nobody will know that you’ve done anything at all.”
-God to Bender; Futurama
@@Flumphinator I spent my entire career fixing problems so no one would even notice there was something wrong. No one ever says after a rainstorm, “Wow, my house didn’t flood.”
One of my favorite trivia is that the fading glow from the time bubble in Terminator 1&2, was achieved with retroreflective paint and an orange light on the camera that slowly dimmed throughout the scene.
Also used in at least one scene in another film to make it appear there was a light in the window in a cabin on the far side of a lake, they set a 3M panel in the window and hit it with a spotlight from the camera position. Not
Enough light to add much illumination to the scene from that distance but the window really popped.
The honey-comb pattern on the reflective tape heat welds the protective top layer to the reflective underlayer. You need the layers to stay in close contact with each other to minimize the scattering of light that would increase if the layers were farther apart. It could be triangles or squares, but those would obscure even more of the reflected light. Another reminder of how amazing bees are 🐝👍🏽😀
I understand that bees do not actually build hexagons bit little tubes. Those then squish together to form hexagons. www.discovermagazine.com/planet-earth/scientists-explain-the-amazing-process-by-which-bees-make-hexagonal-honeycombs
Hexagons are the bestagons
@@robertwernecke2628 neat
@@robertwernecke2628 Bees use of hexagons was entirely accidental, based around their evolutionary needs; like all other evolved traits.
Bees aren't amazing, evolution is; any species could've been the one to make that hexagon shape, and infact other animals do.
The hexagon is not a feature of bees, its a feature of nature.
Hexagons are the most efficiently packing shape, which uses the least amount of building material to fill the most space on a flat plane; so all animals which form small hive like structures are going to form hexagonal shapes; by virtue of evolution.
Wasps produce hexagons by literally MEASURING with their antennae, a lot more similarly to people's construction through use of measurement, making what they do substantially more "intelligent" than what bees do.
The perfect measurements of hexagons occurs the same no matter the species; bees produce Jewelers Hexagons and tightly build them one off of the other through molding the wax whilst wasps form slightly larger perfect Jewelers Hexagons through continually building intersections, inevitably leading to a perfect hexagon pattern.
Either way, it was never bees.
Honeybees are invasive, and damaging to native bee populations.
CGP Grey actually made an entire video ranting about how awesome hexagons are, and yeah it makes sense that they'd be used for that kind of application. Most efficient way to tile a plane with the least amount of lines!
"This is a cat."
It doesn't get better than this! Now I know why I have been a Patreon supporter since the very beginning for Technology Connections! :)
I was caught off guard for having an actual cat instead of the device.
Awwwwww
Someone owns a pretty kitty
This moment was a literal LOL for me.
@@notfirefox599 prettiness is the default for cats.
I spent the whole video wonder: "When is he going to get to that 'Deflective' part?" Then, it dawned on me. Oh. He DEFLECTED the question. I feel smarter now.
Traffic engineer here. Just wanted to say thank you for the thoughtful and thorough explanation of retroreflectors and how we use them in traffic control devices (with a quick reference to platooning sprinkled in there).
"Come quick Ma, the Toaster Guy's on UA-cam again."
This is how my dad knows him!
Why''d she have to be quick? It's UA-cam, you _can_ pause the video and wait for her!
Now that's a really good comment. He is quite well known for his toasters
@@LaMirah dude, just imagine a boomer and his/her mother using a tablet after the great grandchild painstakingly taught them how to "do the computer", like Jed and Granny Clampett. Dangit Daniel, wrinklies are funny and I'm poking fun at them. And I am one.
... loved the toaster video haha
The hexagonal “glue” line is actually support to keep the top surface spaced from the backing and retro reflective matrix on the background support
It also helps in waterproofing. In the old days, road direction signs in the Netherlands where blue backing with white retrereflective lettering on them, and over time the letter's edges got very jagged by water ingress (where the honeycombs were open). Nowadays, road signs are all retroreflective with a semitransparant blue backing over them, with cutouts where the letters go, with the added bonus that the blue colour of the sign stands out more, other than just seeing the letters float in mid-air.
@@IIVQ I work in a sign shop and yeah youre right they are phasing out the white reflective letters cause the high intensity just works better plus you can print on it and laminate it, further waterproofing
@@TommyWashow YOu know you have worked in a road sign shop when you have small dots of high-intensity reflective sheeting all over your clothing or coveralls.
@@TechGorilla1987 i have nasty chicken legs and the corners from trimming deliniators fall right into my boots
HighlandSteam is correct on this, but it is not a "glue". The top layer will lose all its retroreflective properties if anything touches the microprism surfaces, be it water, dirt, oil or glue. During manufacturing, the top layer with the microprism coating (on its underside) is ultrasonically welded to a bottom layer that acts as structural reinforcement and a carrier for adhesives. The tiny hex shapes are the result of this welded hermetically sealed "pocket" between the adhesive back layer and the top film. (my career is converting these films for other uses beyond road safety)
"And of course, putting retroreflectors on those hazards themselves is also a great idea."
Before this decade is out, this country should commit itself to painting EVERY DEER in retroreflective paint.
We could pay hunters to use reflective paintballs instead of bullets, it’s genius!
They've actually tried this on reindeer in Finland by painting their antlers. Didn't bother the animals, and made them incredibly visible to drivers. Only issue is that reindeer shed their antlers once a year. iirc, it was just an experiment, so idk if they'd ever actually implement it
That would give the hunters an unfair advantage
And those damn jaywalkers
@@loganl3746 just paint the fur then lol
In one of the early scenes you can spot eye shine from wolf spiders when illuminated by his phone. That would have been a fun thing to note in the context of this video. Wolf spiders have pretty brilliant green eye shine.
Former surveyor here. While you are absolutely right about one of the most common methods of taking surveying measurements (using light pulses bouncing back from retro reflectors), the tools you showed are different. The first was a level (or maybe a theodolite) and the next two were GPS receivers. Neither of those tools emit any light to take their measurements. Total Stations are the tool you were referencing: en.wikipedia.org/wiki/Total_station
What most people didn't notice, this video was actually done my Technology Connections evil twin brother. Technology reflections.
Or maybe it's Technology Deflections?
Or his helpful cousin, Technology Suggestions.
"...were inspired by the eyes of a cat. Let's take a look at one."
*Me expecting him to pull out a road reflector*
"This is a cat."
*ded*
And since he's talking about its eyes, naturally it refuses to look at the camera.
Yes, this was the most pleasant surprise on this channel since.... possibly ever! (and one of the more entertaining ones, too!) :D
His twitter has been absolutely cat-tastic, it's so cute.
Purr-See Shaw.
@@renakunisaki >>> CATS gonna CAT. 😉
Another Neat Use Case (idk if someone covered it in the comments already oof) is for 3D Scanning/Motion Capture.
That is what those shiny ping pong ball looking things are, spheres covered with retroreflectors at known distances so the computer can do a bunch of trigonometry and stuff to know where the person’s limbs / robotic arm etc are.
This is the “passive” method; some just use light up regular diffusive ping pong balls like Sony’s PSVR controllers
"you're driving a two ton machine capable of killing people" I've used that same argument almost word by word
for exactly why I should not be behind a wheel.
I prefer 2-ton flying deathtrap.
I drive something that can weigh up to 40 tons. I have no clue why people want to play around with it so much. Cutting me off, not me over, ECT. Fn nuts...
@Cristian so have I lol
I've used it countless times myself. It's shocking how many people out there want the responsibility of driving without any responsibility.
"These reflectors were inspired by the eyes of a cat. Let's take a look at one."
.
.
"This is a cat."
Looks just like my cat too
Wolf Avatar Spell it C-A-T. See the cat. The cat has a hat.
I actually laughed out loud.
Came down looking for "This is a cat".
@@enterpriset ditto
We have the reflectors on the moon to measure how far away the moon is, in case it ever tries to sneak up on us again.
We're watching you, Moon, don't try anything stupid
Or fly away from our FLAT DISK
If the moon does do anything, we have venus and Mars on our side!
I've seen that asshole sometimes on the sky. Do they threaten it with guns to go back to space, because it also disappears for a while.
Ah, explains the headline Google News served up to me yesterday. It was "September full moon arrives early". They must have caught it trying to sneak up on us.
@@Kalvinjj nonsense, we couldn't have put anything there. Most likely they're just measuring the distance to the TV studio where the moon landing was filmed. 😂
My mom got a bunch of retroreflective beads that were leftover from the engineering projects at her work, so I got to use them in some fun ways such as a fully retroreflective vest as part of a halloween costume so when a car came by I would glow super bright to the person in the car or to people with flashlights. It was hilarious.
One of my favorite things is being the only car on a freshly paved road at night, especially when all the reflectors are brand new.
That velvety black, the stark, crisp white... There's nothing quite like it.
Glad I'm not the only one
Add a little water or snow to the reflective painted lines and they disappear! It's always easier to drive at night when the road is dry. Those "cat's eyes" get filled with dirt and don't work either.
I'm Canadian and for many years we didn;t have cat eyes. snow plows and such would just scrape them off. 25 years ago I was in California for business. Rented a car and drove late night from San jose to Santa Cruz on Hwy 17. NEwly paved, new cat eyes. I felt like I was in a video game! Loved it and never forget it.
@@davidvoinier6008 What we call "cat's eyes" nowadays is a more modern device which uses the retroreflective surfaces, not the traditional ones with the two glass beads. The newer ones are far less prone to obscuring through dirt and grime, but can still be susceptible to other problems.
"This is a cat's eye reflector. Let's take a look at one!" I did not expect the cat and laughed way too hard.
Same.
Is it his cat? Or his neighbor cat 😀
20:46 According to Wikipedia, with those retroreflectors, the lunar distance can be measured with an uncertainty Beyond Belief (tm) -- or about 1.1 millimeters.
what i always wondered about is, light travels at different speeds while passing through materials of different densities. so when measuring the distance to the moon, do they account for the density of the atmosphere? and if so, isn't the density different at different temperatures?
i assume they use the travel time of the lasers to measure the distance.. because those reflectors on the moon must be too close to eachother to measure an angle right... right?
@@sliceofbread2611 There is some accounting for things like that, but it is imperfect at best. It is one of the number things that lead to the margin of error of about 1.1 mm.
@@sliceofbread2611 Yep. I was in a place where USSR did their experiment. I saw this big ruby laser, which was fired into the moon. USSR used a reflector on their moon rover for this purpose. And yep, they accounted for the density of the atmosphere. They did this experiment on their long-range communication station. This station can send and receive signals till the end of solar system and have a lot of sensors for temperature and atmosphere state.
And then there are still people who believe that no-one landed on the moon.....
@@abiosismlg613 i do not want to start a thread about this topic here, but most people i ask about this simply state that they did not go to the moon that early, and that they went there later..
can't wait for the moment people go there again and can confirm the landing modules actually being there.
@19:00 You mentioned how often retroreflectors are used on bikes and cars before. There'd be so much potential for a garage door to errantly think it was clear due to an obstruction that reflected the same light back.
Oh, good point! I should know this, my new bike's tyres have retroreflective strips. I wonder if that's why a barrier at the exit to a caravan site wouldn't work until I turned the bike sideways...
This reminds me of an old motorcycle adage "Treat every vehicle on the road as if it's trying to kill you."
Man, if that aint just the truth. I'm riding in a Jeep Grand Cherokee and I still think people drive as if there is no tomorrow.
“ . . . Because they are!”
I find it pretty funny in the motorcycle handbook in my state it puts a lot of effort into telling you most people on the road is at all qualified to be on the road. But the people that write the books are the same people that let those people on the roads. And in the car driver's handbook it assumes people know how to drive but make mistakes.
Oh my sweet summer child... *Laughs in bicycle*
@@philipc7273 Riding a motorcycle is significantly more dangerous. Walking is actually more dangerous than riding a bike (and riding a motorcycle for that matter) but all of them are more dangerous than a car.
I can imagine that the honeycomb pattern reduces stress when the tape is bent.
I was thinking it might actually be to make it more noticeable because it's not a solid block of light, maybe?
@Johnny Thousand I think so too. There is a body of evidence about reflectors being camouflaged against other reflectors. In the working on the roadside safety course I did many years ago, this was explicitly explained, with pictures of people with a hi-vis jacket being barely visible standing in front of a police car.
We have so many now. Adding borders, and distinctive breaks, helps to separate one from another.
The honeycomb pattern, and various other patterns printed on the front of prismatic sheeting, is there to identify the brand and quality of the sheeting. The manufactures provide samples for inspectors to compare with the signs the (always low bid, since the signs are owned by some part of government) contractor put up, so the inspector can determine that the signs meet the specification.
@@JohnnyThousand605 it also would reduce the overall brightness to more tolerable levels to keep from momentarily blinding people
Moving to Colorado made me realize just how much I relied on the imbedded reflective markers. CO mostly doesn't use them because the snow plows would just rip them off of the road surface. I also found out that yarn with a thread of retroreflective fiber is a thing, and now I often crochet reflective stripes into beanies and scarfs.
I have been on roads that have ahallow grooves cut into the road surface for the reflectors to be mounted below the road surface and thus they are protected from the plows.
@@daymichaelv2 ahh Texas should do this.
Thin retroreflective threads are everywhere. The guyline I bought for camping has a retroreflective thread wound through it. Anyone who's tripped over guylines wandering around the campsite at night time can appreciate anything that makes those bastards more visible.
Heh, now I’m imagining a Colorado grandma that sews high-visibility scarves and sweaters for her grandchildren.
@@scrubbbsyboy844 sounds nice.
The survey instruments shown here are an Automatic Level then 2 different GPS receivers. Neither use prisms (reflectors). The instrument that measures distances is called a Total Station. They are pretty cool and work in truly amazing ways.
As someone who drives professionally, I wondered why older road signs are easier on the eyes at night than new ones (but didn't care enough to find out).
Now I know. Thank you!
Insufferable pedant alert: The angle of incidence/reflection is the angle between the light beam and _an imaginary line at 90° to the surface of the mirror,_ not between the beam and the mirror itself. Obviously it makes _absolutely no difference_ in practice, but it's a fun physics fact.
You adopted a cat purely as a visual aid for this video. That's dedication!
We call it the surface normal in computer graphics. And it's the angle/line perpendicular to the surface.
It makes LOTS of difference with a curved mirror, but none with a flat mirror. Or, so I learned in high school in the 20th Century.
The imaginary line is the normal vector of the surface.
It does make a difference with a curved mirror, for those you either have to use the conventional method (measuring from the normal line as you describe) or measure from an imaginary plane tangent to the curve.
Additional pedantry: the imaginary line is not so much a fact as a convention used to make teaching easier. It would make more sense to say the angle will be the same wrt the mirror when explaining flat mirrors, but would make the explanation for curved mirrors more complex where you would have to consider the plane tangent to the point of incidence. To keep the "definition" the same for all mirrors a line normal to the point of incidence is used. You were absolutely right when you said it doesn't matter which way you think of it, as long as you don't mix it up for yourself
When I was cycling to school my dad got me a reflective vest. Pretty much everyone who saw it commented something to the effect of "you can't be missed!" and after maybe 2 weeks of this I got fed up and started responding "Missing me is sorta the point of having it"
Before I was put on stand by, I would walk to work. After years of almost being run over by careless drivers I started wearing a traffic safety vest during the walk. My problems were reduced, but drivers are still careless idiots.
@@williamvergerwolf150 walking on the side of the road i often get drivers who drive closer and closer to when i am walking. like a homing missile. i dont know if they are purposefully targeting pedestrian or that they are accidentally driving crooked towards me.
@@Francois_Dupont I can't answer that, but it's normal to unconsciously steer in the direction you're looking if you're not careful. I guess this means they saw you and were watching, if only they'd realize they were getting too close..
@@williamvergerwolf150 this is what also think, but its still scary when they are coming at 100km/h and drive 2meter+ sideways from the original position.
"learn how it works, and how to use it properly"
I wish I had teachers like you when I was a kid. They should have really driven home how dumb most people are. You do great work.
It's not so much that people are dumb per se, but the world is much more complex than the average person can handle. Even if you were educating yourself every day you'd still make stupid mistakes.
“luckily, i have one right here!”
oh he’s going to whip up a cat’s eye
(puts cat on table)
MAY I recommend some nice
science-channel to you? Just because, well, the learning never ends, duh?
“…and through the magic of buying two of them…”
@@scrubbbsyboy844 (puts a partially disassembled cat on the table)*
“Drivers are careless idiots”
Me: *subbed to three or four dash cam channels* .......yeah
yes.
Absolutely
As am I. It also helps to be a professional driver. I seen some shit...
For about four months I would encounter some guy on the off ramp that had zero rear lights. No brake lights, no tail lights, not even a blinker. These encounters were at 11pm at night.
As a cart clerk at WinCo, I can confirm this is true
This video really speaks to my affinity for city road design and shiny things. Also, that cat is lovely.
Another roadway reflector fun to know fact: If you see a blue one in the middle of the street, it indicates the presence of a fire hydrant.
"Mirrors are great at reflecting!"
Did you know that if you stick a piece of retroreflective tape on the bathroom mirror at night; shine a light on it; and say "Alec Watson" three times; his face will appear and make an appropriate pun.
Martin Gélinas made me chuckle, have a nice day
I tried it and it totally worked!
Ok, he appeared. Now how do I send him.back?
@@sameaster5150 Present him with a modern toaster
I needed many puns. Now I cannot see my mirror for all the reflectors and Alec Watson faces.
16:04 The honeycomb structure is for fastening the upper part which contains the reflector to the lower part. There needs to be space between for the reflectors to work. You can choose virtually any structure but it needs to be a closed pattern - not for instance dots. Otherwise condensation and water vill creep inside the whole area and render it useless..-
My intuition said engineers would not make this aesthetic choice at the expense of the tape's effectiveness.
Also, hexagons are the bestagons.
Solas grade reflective tape has the honeycomb shape but the retro reflectors are formed into the same pattern not square behind. So the one in the video looks like a imitation of a regulated reflective tape.
@@drewmqn 🐝♥️
Thanks for clarifying.
When you're talking about light beams and curtains for safety, it always needs to fail safe. With emitter and reflector, you can get reflection from objects that pass between the emitter and reflector, which could cause the system to fail to recognize the obstruction.
A beam style, with emitter and receiver, while it must be carefully aligned, is immune to these problems. If the beam is disrupted at all, the system will register it. This behavior is more desirable in a safety circuit like for overhead doors, and for automated processes that work with reflective material such as a conveyor counting boxes, and the tape on the boxes reflecting the beam (this does happen, I work in industrial automation, trust me).
You made my point for me (got here a bit late)
I wonder how effective weeding out false positives by having the beam and reflector be specific colours and having a filter over the receiver would be?
@@WJS774 that strikes me as much harder than just aligning the transmitter and receiver
@@eternalskywalker9440 More complex to design maybe, but still easier to install. It's mainly an intellectual exercise anyway.
@@WJS774 it's easier to have the emitter flash in a known pattern, then you can more easily discern signal from noise.
Regarding trucks, you may have noticed that modern trucks have all their front lit by led lights. This makes the truck more visible, but also helps the truck driver see retro reflector signs
LEDs are used for longevity. Reduces maintenance costs. Rare to change a 'bulb' from failure.
I am 100% here for the rant about people who don’t turn their lights on!
Right??!? Yet when I run them over a couple of times, suddenly I'm "at fault" because I was "on my phone" while "eating a steak" and "watching a movie".
So unfair! Oh well, at least the jail cell is bigger than my truck sleeper, but the hookers are uglier
I think it has a lot to do with newer cars having always-lit dashes. We've got a 2018 Toyota and 2018 Nissan and I've noticed the only thing that tells you your lights are on is a small green indicator. The dash lights themselves are always on, unlike on all my older cars. So that might explain the ones driving like that around dusk. But after it's completely dark? No clue....
It's blatant disregard. I'll flash my headlights at them, or even follow them doing it, and they never turn there lights on. They're simply oblivious.
Side tangent: "Turning signals, why do cars even have them?" - every other driver on the road but me
80% of the time, they are driving a Honda CR-V. I'm not sure what the design flaw is with them, but their drivers somehow turn off their automatic headlights.
"This is a cat."
Me: (makes note for futue reference)
I always learn so much from these videos!
I honestly had no idea. I thought those two things wandering around my house were alligators or something but it turns out they they are in fact cats too.
write that down! write that down!
Fun fact! If you ever notice a random blue retroreflector on the road, look to your left or right and you’ll spot a fire hydrant! Fantastic video as always, Alec.
I had forgotten about those! I wondered what they were for!
In Ireland they put green ones on the side of the road before junctions, so that if you're hunting for a side turn in the dark, you're more likely to see it in good time and navigate it safely.
Not "random" then... LoL.
Still fun fact.
@@dozog well, from the perspective of someone who doesn't know that they are distributed randomly :D
@@Daniel-yy3ty So.... Not random anymore 😜
Every single time you do a display of an item in that Dutch angle (or tilt) How It's Made style, I am flooded with good memories. I genuinely wonder how you get the slight pan so smooth and centered on the display the entire time.
Great work as always :)
Re: signs too bright: THANK YOU! There’s a speed limit sign I pass every morning on my way to work that I think exists for one true purpose: to make me blind for the next 1/10th of a mile...
That bright sign is most likely made with 3M's Diamond grade Reflexite reflective film ,those are the new standard in many states such as Maryland which goes beyond the US DOT standards, they are bright,but more costly to purchase,about $150.00 a piece compared to the older industry standard, I got a STOP🛑 sign made with that in my room & it blows all the other STOP signs away in my neighborhood !,it lights up my entire room when the cell phone just emits a little light from the screen, I'll probably get a Yellow "No Outlet "sign made up with actual a 🚫🔌 on it as a joke ! Tired of people asking where the outlet is to charge their cellphones & devices 🤣
Mind you, you still need to see them clearly when you have to dip your lights for other traffic, so they can't be too much dimmer.
couple of those on my road, so stupidly blindingly reflective that you can't read the marks on the sign. More bureaucrats wasting tax money to make the world worse.
14:08 “No, I will not apologize.”
Well played.
please explain :'(
@@saadjamal1000 The linked part of the video was immediately preceded by the phrase "copycats appearing over the years." The "copycats" part was a joke since the part just before that was talking about technology that *copied* the way "cat" eyes work.
@@Ryan1729 OMG I JUST GOT THAT HAHHA
Punsmith 100
Yeah, I put the time stamp a little too far ahead of the joke.
The cats eyes in the road get cleaned by driving over them, the weight of the car pushes the lenses down over a hard rubber that wipes the filth off. Which is a cool design feature!
Also the signs on roadworks have extra light because the barriers get covered in road grime :)
The design also includes a deliberate puddle at the base so they get washed and wiped every time. Driving over cat’s eyes is a public service:-)
Another great use of retro reflective tape is on pet collars and leashes. It gives my pup a lot of visibility, and me a 5 foot strip of visibility leading to the pup when I’m walking at night.
3:26 As soon as the hair hit the frame, I knew we were in for a treat. XD
Neat thing to try near home: Point a laser pointer at a Stop sign, even with a weak laser during the day the whole sign lights up.
Try pointing it at the moon, you'll see a flash if you hit the retroreflector nasa put up there, just aim carefully
@@ohokcool Or you just triggered a nuclear device.
I'll just continue to shine it in my eyes
Sauce you mean there is atomic activity on the moon?
@@EvanzoZubinsky Yah' never know until you find out and put the moon out of orbit permenantly.
We have garage door openers here that use retro-reflectors
You also have kangaroos and alphabetical characters the size of continents!
@@xebek 😂
That is smart.
I see them on automatic gate openers as well
I have seen the reflectors and one sensor... mostly on commercial garage doors, and shop bay doors.
"Let's take a look at one: Here is a cat"
This made me smile uncontrollably
I was hoping it would be followed with "the magic of having two of them," because two cats appearing in a youtube video is magical (sometime dark magic, but still magical).
16:00 One time. I did it one time. The lanes markers WERE red. It was late at night and I had no idea why they were red. Then...a car came from the other direction. I immediately realized it was ME that was wrong but also that I WAS going the way I wanted to...
But there were no lanes to my left...As it turns out though that was the way I wanted to go I had to backtrack to get on the right side becuase it was one of those split highways where North and South are actually seperated by a cliff in between them so you can't see the other. WHOOPS!
Thanks! Now I'll never made that mistake again! So the red reflectors ACTUALLY MEANT SOMETHING? Wish they taught me stuff like THAT in driving school...
What's he saying?
He says we are going the wrong way.
How does he know where we're going?
Yeah how does he know where we're going?
Planes, Trains, and Automobiles.
A summary of state road regulations should be required reading but unfortunately most drivers ed now a days are "what is this sign" and "can you parallel park"
Are you suggesting that you weren't taught to not drive into the oncoming lane?
XD
How did you get a license
"You're reflective."
That's the nicest thing I've heard all day.
11:58 Solution, make it mandatory that deer and moose wear reflective vests at night!
It’s too bad you only see their built-in retroreflectors when they’re right in front of you
And make make it illegal for them to jaywalk.
Did you mean 18:01?
They are kinda doing it www.bbc.com/news/blogs-news-from-elsewhere-26244339
You can tell that to a 6ft kangaroo good luck
Another useful and under appreciated tip is on school busses in America have yellow reflective tape specifically around emergency exits and specifically show how far off the ground the inside floor of the bus is for when it may get into an accident
I'd imagine the reason you wouldn't want to use a retroreflector based system for a garage safety device is...well, you might have left your bike in the path of the garage door, or even just the retroreflectors on the rear headlights of your car that you parked a little too far back this time.
It can only tell that it has an unobstructed view of A retroreflector, not necessarily ITS retroreflector :)
Usually the reason there's power to both of the sensors is that one is an emitter, the other is a sensor. If one was both the emitter and sensor, then any reflective surface could give a false positive. I've also seen these sensors confused if they're in direct sunlight; the door will start closing, and suddenly reverse when the door casts a shadow over the sensor; putting up a little sun-shade around the detector ensured it could only see the emitter.
Wouldn't a laser help with that? Just make the reflector large enough for easy alignment (6-10 cm diameter).
@@georgf9279 how so? How does the laser tell the difference between the light hitting the retroreflector attached to the opposite side of the garriage and returning, Vs hitting the tail reflector of your car and similarly returning directly back to where it came from (it's what retroreflectors do after all).
If you mean the general narrowness of the beam meaning less chance of hitting something reflective, perhaps true, but probably not something to be relied upon (if it fails ,that thing is in the worst place)
Only thing I could think would be maybe some time of flight stuff, but that's gonna be complicated.
@@AngDavies
My opinion:
A laser would have not only a tight beam, but also, as pointed out in the video, would be able to be used to measure the distance from the emitter, retroreflector, and back to the sensor. If the chip in the garage door opener is fast/smart enough to know what the correct laser timing is, it could figure out the difference between the correct reflector and an incorrect reflector.
true especially with dual garage doors where the sensor for the next door might be almost parallel
Interesting fact about the reflectors on the moon: Apparently they're getting dimmer. The most likely culprit is dust buildup. As the moon has no atmosphere for dust to float around in this was... unexpected. The most likely hypothesis is that the dust is being deposited from micrometeorite impacts, and that such impacts are much more common than anticipated.
Lunar dust floats around there due to static electricity, where it can levitate and travel vast distances. The charge is provided by solar radiation.
Lunar dust is actually VERY electrostatically active, and objects can easily build up a charge with no atmosphere to dissipate it into, or to block the heavily ionized solar wind. Moon dust can actually get so electrostatically charged by solar wind that it "levitates"
also getting futher away.
Bring a can of compressed air to blow the dust of, perhaps? I wonder if that would work still work with no atmosphere.
@@chrisstorm7704 The worst that can happen is either the can exploding or the user being pushed into space
19:50 focus on his nose and when it goes black and white there's an optical illusion and you can still see some colors.
pretty cool accident
whoah!
That's cool and interesting. How does it work?
So cool!!!
@@xm1ch161 Your brain is filling in the caps from the previous information when you saw colors there. Basically your brain is doing the video compression to save processing time :D Notice that you can only see the colors when your eyes are not moving, otherwise visual data changes and you see the actual color of the image.
Pump Gun is Shit They're called Negative afterimages. There's some information about them online but I don't understand them very well
I love how unstructured the video appears and how I still learned a lot from what you said, even though at times it just seemed like continues rambling. Liked & Subscribed.
11:12 THANK YOU. It is incredibly scary seeing the amount of people driving around at night that have NO IDEA how their vehicle lighting works! The whole automatic headlights thing is great, if your vehicle has that option (both mine do) but there are so many different vehicles out there that purposefully seem to make it difficult to tell when your lights are actually on vs when they're in DRL mode.
Around here, a lot of newer model Dodge Caravans always seem to be driving around with their lights off when seen from behind, and when I first noticed this and drove past one, I noticed their dashboard was fully lit up! WHY is it set up that way when these things don't have automatic headlights‽ It just proves how oblivious drivers really are and it's terrifying sometimes!
The first thing I do when I get into a vehicle I'm unfamiliar with is figure out where all the switches and things are and what they do, so that I can prepare myself for properly operating the thing. But I guess that's due to too much common sense on my part, and expecting others to follow accordingly.
my car has automated head lights but it doesn't show any icon in my dashboard when they're turned on.
My late-model Subaru has illuminated gauges as well, but if the headlights are off it means the gauges are garishly bright. So, at night, if my gauges are practically blinding me, it’s a clue to turn on my headlights so that they dim to a reasonable level. Of course, during the day, the very bright gauge backlight is perfect to have. I wish more manufacturers adopted this standard.
My 20 year old Pontiac has automatic headlights. It's surprising that it's not standard across all cars when it was a thing on a relatively inexpensive model of car in the late 1990's.
@@rgiaco777 My dad's Nissan Altima attempted to utilize this trick, however, when you're driving in a well-lit area, or you begin driving during daylight hours and continue through sunset, it can take a frightfully long time for that "garishly bright" lighting to begin to be uncomfortable and hint to you that maybe your headlights are off when they should be on. I personally always preferred to have an unlit dash during the day, which is designed in such a way that the instrument cluster can be well-lit by ambient light (i.e.: don't sink the gauges halfway down to the engine block). I've also become annoyed at having automatic headlights, as with my late Toyota Corolla. In that case, I am unable to signal oncoming drivers that THEIR headlights are off by turning my lights off and on again repeatedly. Because my headlights are automatic, it prevents me from turning them off when there is insufficient ambient light, thus prevents me from issuing the "your lights are off!!" signal.
Some manufactures have implemented measures to alert drivers to you turn on their headlights when it is needed. VW used to turn off their gauge lights at night if the headlights weren’t on. I had a 06 Pontiac Grand Prix that would alert me that headlights were suggested when it was dark enough and the switch was in marker mode or off. My work had a 09 Silverado that would turn off the gauge lights at night when the auto headlamp system was disabled.
Ok so I'm I'm sat watching, nodding along, learning, amazed at how such a simple thing can be so effec... LOOK AT THE KITTY!!
"This is a cat"
Incorrect. That is a HANDSOME BOI
I love this channel and how Alex brings curiosity, science and great commentary to light (especially in this segment).
Some of our National Parks employ a few of these retroreflective markers near some of their wilderness trails. Ask me how I know? One beautiful November day, we went on a lovely hike in Arches National Park through a region aptly named “Devil’s Garden.” Having begun in the afternoon, as the sun got lower we knew we should probably turn back. But there was just one more magnificent arch we had to see. We were equipped with day pack, jackets, headlamps, paper and preloaded GPS trail maps on our smart phones, snacks, and water. So, of course, it did get very dark very quickly. We were able to retrace our steps back to a familiar, large well-marked trail sign at an important fork. It was only a few miles more to the parking lot. But then, not thirty feet past the sign, we lost the trail. We could clearly see trails leading to places other than the parking lot. But, no trail leading home. We were at a convergence of at least 6 rock structures known as fins, the very structures that make the arches. They are harder rock left standing as erosion removes soil and softer rock from the valley. Some of these fins arise several hundred feet above the valley floor. Some start out as broad paths, but the area is aptly named because after ascending twenty meters or so above the valley, they just peter out to a sheer drop! Good thing we had our headlights! We must have gone up and down, back to the big sign a dozen times. GPS said we were spot-on the trail, but every direction from the sign we took led to danger and disaster. Then, looking down a broad and sandy wash that looked nothing like a trail, my headlight picked up one of those retroreflectors about 250 meters away, nestled among some shrubs. A trail marker? Were we saved? Let’s find out! Down I scrambled to the marker. As I got close enough, I could read a message. It said, “Not a trail. Danger!” Behind the marker was thick scrub and an increasingly steep descent down to what I then suspected might well be hell. The retroreflector to the gates of hell! Well, alrighty, then. All that for nothing. Huff and puff back up the hill to the big sign one more time. I thought we might just have to spend a very chilly night in Devils Garden, knowing in the morning, hundreds of park visitors would flood the trail. Wait a minute. Why not throw up a prayer? It couldn’t hurt. So, after asking for a “sign”, I passed a scrub pine tree at the base of a steep rock not far from the big sign. I had seen it several times that night. But this time my light caught an important detail. Some of the bark of the tree was smooth and white, well worn, as if thousands of hands had grasped the tree to get a purchase onto that steep rock at its base. It was a sign from heaven in Devil’s Garden. That steep rock was the foot of the fin we needed to take to get back on trail. I sure would have appreciated a retroreflector arrow at that tree trunk pointing the way home, or even a neat stack of rocks. Nevertheless, in no time we were at the parking lot, where our lone car was still waiting for our return.