How to Melt Cars and BBQ Pigeons - Sixty Symbols

[@aengle.]

Thats the best urban myth ever! I can imagine someone like Karl Pilkington mentioning it... "Alright? There's a pigeon death ray in Nottingham"

[@Kofeina19]

Please consider putting english subtitles in your videos. It would make a huuuge difference for many watchers that know english quite well, but still may have problems with such science talks. BTW it's great that you respond to the recent events and do videos explaining them, it makes your channel subscribe-worthy.

[@magicalpencil]

troll level = professor

[@jcfreak73]

I love how him saying that they are intentionally avoiding BBQing pigeons becomes "Pigeons Are Being Barbaqued" in the news.

[@elave16]

the effect works for only 2 to 3 weeks of the years due to the sun positionr elative to the building

[@ChrisTheGregory]

3:10 I believe in this case it would be called deathraytracing.

[@sixtysymbols]

yes - a few here on sixtysymbols and LOADS on deepskyvideos

[@RQLexi]

Your profile picture is magnificent. As for the building: there is really not all that much that can be done about it. The Walkie Scorchie is nearing completion, and for the time being, the people responsible are only saying that the phenomenon will stop come autumn, but offering no lasting solution. Any solution they do come up with will most likely be an absurdly expensive affair.

[@jinchey]

"Your car has melted. Please come and see us. From the builders"

[@IstasPumaNevada]

Good question. I suspect they'll need to attach something to the reflective surface, perhaps shades over the windows or a coating on the windows' surface that scatters the light rather than reflecting it as much (though that would inhibit the view, so probably not that).

[@louistournas120]

There was a video somewhere from a company in France. They had a large reflector, I think 5 m in radius and it concentrated the light onto a 5 cm radius area. They were able to melt an iron plate in 30 seconds (mp = 1500 C).

[@Muck006]

There is a solar power plant in Spain which has loads of moving mirrors which project the sun on the top of a tower, where the heat is absorbed by liquid Natrium to the generate power.

[@pacogoatboy]

They were unable to easily light a wooden ship on fire using relatively small mirrors. That's very different from heating up a stationary object with a mirror the size of a skyscraper. It's entirely possible to gather huge amount of solar power in a very small volume using mirrors, check out "concentrating solar power plants" for more info.

[@karlitohomes]

The architect of the "Walkie-Talkie" building also designed a condo/hotel in Las Vegas called Vdara, which has the same problem! In this case, the sunlight was focused on a pool in the hotel grounds and it gave a few people some unpleasant burns. I'm amazed this guy was allowed to repeat his mistake in London.

[@Rafaelfl2]

In a flat surface, like the one in the video, yes. It makes more sense to think about it in other situations tho, like in the building(a spherical mirror) for example.

[@puncheex2]

A static power tower works exactly on this principle. One was built in California in which a several hundred "heliostats" (3x3 meter motor driven mirrors) concentrate sunlight on a steam boiler. There were definite worries about blinding pilots and such in the immediate area of the plant. They definitely had some par-broiled birds who flew through a concentration of beams.The plant was decommissioned a few years ago, after working for 20 years. It's visible in Google earth at 34.8719, -116.8342.

[@goshisanniichi]

There's a hotel in Las Vegas with the same problem. I think they alleviated it by slightly changing the angle at which every pane of glass was mounted so that they didn't have as much of a single focal point.

[@trespire]

There are several designs that focus solar energy & convert it to another form of energy. If you are interested you can search for Heliostat & solar furnace.

[@Duncan_Idaho_Potato]

I read somewhere that it's a simple matter of putting a special film on the windows to reduce the reflectivity of the glass.

[@sharplikerazor]

That's such a good yarn about the pigeons! I saw Anish Kapoor's exhibition in Sydney, including the sky mirror, and I thought that it must make astronomers very happy. BTW, you'd think that someone in the architecture firm that designed the death ray building would have picked up on what it would do

[@Pseudoradius]

The advantage of using the normal is, that the normal stays a straight line when you go from the reflecting line in two dimensions to a reflecting surface in three dimensions, while the tangent becomes a plane. In two dimensions it isn't that much of a difference, but that doesn't mean that the difference isn't important.

[@Yheffez]

Another thing that should have been pointed out is the location of the different focal points, in the case of Nottingham's mirror, it seems as though it's pointing slightly upwards mean people wouldn't be really harmed where as the building's focal point seems to point close if not spot-on to the sidewalk.

[@DevinWatson]

I remember reading an article on the skyscraper and wondering to myself if Brady would make a video about it. And I'm glad you did!

[@coxfuture]

it's a rare time i laugh out loud when i'm on youtube. the professor's story about the newspapers was one of those rare times. this gets a like from me.

[@NthPortal]

Thanks :) I agree, there's no really feasible solution to the problem. Rebuilding the building, though it would work, would be far to expensive to even consider. Although, I wonder if they might accomplish something by re-angling the windows so as not to be parallel to the curved surface of the building...

[@MonsieurArlequin]

Brady I would like to thank you for all your videos, Most of what you put up are somewhat related to what I'm studying.

[@flashpeter625]

The Ivanpah solar power tower facility has "cooked" some birds mid-air. But of course that is a purposeful concentration of sunlight with hundreds degrees Celsius in the focal point.

[@spinnenente]

yes there are power-plants that use a large array of mirrors to heat water or oil so that the heat can be used to drive electric generators

[@sixtysymbols]

you're welcome

[@garryentropy]

excellent in all parameters

[@iabervon]

At MIT, there's a building that was originally designed to have an atrium with a huge glass sphere in the ceiling. One thing about transparent spheres is that they focus all of the light that enters them such that it all goes through a single point, which would have been far off the ground. But the joke was that the building was so ugly that it would cause birds to burst into flames if they flew through. And then they decided to leave out the sphere when they built it.

[@IMortage]

Awesome coincidence (that Prof. Merrifield could contribute such a nice story and background to this also quite interesting story about the Walkie Scorchie).

[@rogerwilco2]

I live in the Netherlands and I had heard the barbecued pigeon myth. Nice to know the full story.

[@DanielDJB]

Could you link in the planning application URL or document? This would be a good lesson on law of reflection for high school students. I have been unssuccessful in searching for original planning application

[@brainfaqk]

where can i buy a concave mirror?

[@Lampropeltis773]

In Las Vegas there is a similar phenomenon at the Aria casino. The facade concentrates sunlight onto a pool deck, melting plastic bags and shoes. We call it the "Death Ray".

[@Dalxein]

I was just about to say this. I'm glad someone beat me to it. Very good idea to put solar panels where someone's already focused the light, to cut down on the cost of building focusing mirrors in the first place. Especially if you can't park there anymore for fear of melting your car.

[@schooptec]

even if the parabolic mirror is on the north side. just some more mirrors on the opposite side are needed to catch enough sunlight

[@danielcooper1131]

there was one of these archimedes rays in vegas due to a semi-circle shaped building. Locals called it the "Deathray"

[@wupme]

+Daniel Cooper it was designed by the same failure of an architect.

[@SpiderWeb1965]

Brilliant - according to the Nottingham Playhouse web site: "Contrary to media speculation Sky Mirror does not pose any danger to the public or pigeons in the form of a barbecue ray." nottinghamplayhouse co uk / about-us / sky-mirror

[@Heatseeker1]

No, focal length = radius of curvature / 2. This means that for the building you would have to be within a 100m or so by the looks of it.

[@AceSeptre]

Are there going to be any more videos from your trip to Chile?

[@S4R1N]

Aha, that's fantastic, having your own urban myth is awesome.

[@wupme]

+S4R1N its not a myth, this really happened. And his building ins las vegas was responsible for burned skins and melted plastic cups.

[@joshuahadams]

+djteac the Mythbusters tried to make a "solar deathray". They could cook with their revised version, but only if it was angled properly, and it's focal point was pretty close.

[@FlawllessCowboy]

What if they put solar panels at the focal point

[@SuperSiggiboy]

+FlawllessCowboy If light is too concentrated at the focal point, the fine circuitry of the solar panel would melt, and the solar panel would be destroyed. What a bummer. However, there are solar power plants that use mirrors to concentrate light to one focal point, where they usually place a black container filled with water. That water will boil, and they will feed the steam into a steam turbine and generate electricity that way

[@gagaape]

+FlawllessCowboy According to the Professor's diagram, the focal point is underground. But I get your point.

[@kamoroso94]

+SuperSiggiboy If the concentrated sunlight was too intense for solar panels, couldn't you just put a convex lens in front of the panels to diffuse the light enough to spread over its surface?

[@wilurbean]

It could be an art installation. The sun's lateral movement, like how it tracks back and forth across the sky as the year wears on, would cause the focal point to move left and right in an arc. So cut out that arc in the ground and have the collector move with the sun on tracks slowly through the year. It'd be like a giant solar clock, or modern Stonehenge.

[@wilurbean]

Secondary reflector bruh. Actually wouldn't the diffuse light before the focal point be better for the solar PV? Larger area of light with less intensity.

[@lesconrads]

You could also have talked about this ginormous solar furnace in France, where they have a ton of heliostats AND a concave mirror in the end, to get very concentrated sunlight. It is in Odeillo, so wiki it some time :)

[@stormthehouse]

I wonder how they're gonna modify the building to prevent this from being a problem in the future. My guess is they will adjust how the windows are situated so they're perpendicular to the ground instead of following the curve of the building, resulting in a slight overhang above the windows but otherwise preventing the light focusing problem they have now.

[@somewony]

I don't think the light gets reflected because the windows aren't quite perfect. This is done on purpose, for insulation. It prevents the air inside the building from heating up too much.

[@MarcEgli]

How do you mitigate this issue? Close the road in front of the building during february? Is it even allowed to reflect concentrated light from a building?

[@jamborossrs]

Love this channel. As well as pretty much any Brady channel :)

[@ScienceSeance]

What a fantastic channel this is. Great stuff.

[@brainfaqk]

you mean the inside of a metal bowl? :D i rather thought of a big mirror to scorch things :)

[@LtShifty]

It would melt too, solar panels have a major flaw in that they cannot utilise magnified or focused light energy due to the heat generated. However a liquid salt power system would work quite well, given the sun is shining in just the right spot :)

[@rhoadess]

Dear Mike Merrifield and anyone else, Is there a way to design the angles of a surface so that it will allow minimal heat radiation to be absorbed. Such an idea might be applicable to car design, such as the angles of windows and even building windows, thus keeping a place in hot areas cool. I suppose in the winter you might not want this, but I would rather have to heat the car in the winter than cool down 160 °F (71.1°C) in the summer. I wonder if stealth technology might be useful for this?

[@jerradn]

At which sun angle (or relevant days of the year) is the sunlight concentrated the most?

[@ZoggFromBetelgeuse]

This error doesn't really surprise me. In Benidorm, Spain, they built a 47-story skyscraper without elevator.

[@SlimThrull]

THANK YOU! You said the rays from the sun were essentially parallel. I was told by my 9th grade science teacher that there were in fact exactly parallel. When I spoke up and said that wasn't right. I was told not to worry about it. I continued saying I could prove it (which is super easy to do even for a 14 year old). After proving it, I was promptly kicked out of class for the day. Thank you for getting it right even if its a bit harder to explain. Thank you, thank you.

[@Apjooz]

The building had glass windows and only slightly concave wall though vs perfectly concave mirror.

[@dhughes1969]

Someone will quickly be browsing KZbin and will see a Sixty Symbols title "BBQ pigeons" and the legend will be reborn.

[@unvergebeneid]

They should used mirrored windows and make a solar thermal power plant out of the thing. Might even be a model for future buildings that double as solar power plants. Genius architect in retrospect!

[@anthonyh137]

Probably not. Telescope mirrors have to be ground very precisely so that all of the light is focused at the same spot. If not all of the light is focused properly, the resulting image is distorted. This doesn't matter for simply concentrating sunlight, obviously, but for looking at distant stars and galaxies distortions are very bad.

[@RobertDeloyd]

LOL! Loved the pigeon story! Thanks :)

[@RQLexi]

Any form of reconstruction of even aspects of the building, including re-angling of windows, would probably be extremely expensive (and with some solutions ruin the facade of the building to an extent I believe the owners would deny, no matter how important). Another problem is that the building has already become a landmark and a symbol. Any changes should be subtle.

[@danthemango]

"it was a slow newsday nationally and internationally"

[@bentoth9555]

I remember actually seeing the ABC news story about the BBQ pigeons here in the states.

[@NickRoman]

And it tells you something about how news reporters (or their editors) deal with things.

[@thepeff]

Would it be worthwhile to engineer a building so that it would also be a large telescope?

[@tc225k]

The weird thing is, this wasn't the first time it happened before. There was one like this in Las Vegas

[@jipersson]

The building also looks concave in it's width, adding to the vertical effect.

[@Andrewsarcus]

Talking about reflected light, just how many rainbows can there be in ideal conditions?

[@unamaxify]

especially because he has done it twice the same architect designed a hotel in las Vegas (now known as Death ray hotel) that caused hair being singed by concentrated sunlight.

[@RagingGoblin678]

so if they cant calculate were the light is being concentrated couldn't you put the solar panels in that region some were and get direct light from the sun and indirect focused light from the building thus increasing power production ?

[@a1qcaguy]

You guys rock! Thanks for the entertainment and knowledge...

[@toyotaprius79]

If I recall, those are called Parabolic Solar panels. I doubt it would get interest though, few people are interested in solar while many others associate them to the solar panels that are decades obsolete.

[@Ichbindereine]

Yep, ASAP as possible

[@Rafaelfl2]

Just a little input to Brady: The incidence and reflectiona ngle are not measured the way you did on the video. You don't consider the angle between the surface and the light, but the one between the light and the normal line

[@Veon1]

There already exist several power plants, called "Concentrated solar power plants" (google it), that work just like that, focusing the sunlight using mirrors and converting the heat into electricity. They are indeed often located in deserts :)

[@DeJayHank]

Wow. It's really interesting to learn an example of how an urban myth started. And it's not just speculation, it's guaranteed 100% true since you were the one starting it. Very interesting.

[@SID480]

well yeah, and in this case it is the same because the surface in the video is a flat surface, but had it been curbed it would have been hard to draw the angle of incidence and reflection unless you draw them between the light and the normal.

[@TheChunguTube]

It would have been good to mention the application of geometric optics to produce energy like the PS10 solar power plant for example

[@StreuB1]

This was an awesome video. :-D

[@VladVladislav790]

Of course no pigeons were harmed in the production of that thing, because they were afterwards, when it's ready.

[@Poponfu1]

They are already doing this in spain.. well heating up molten salt. But the concentrating sunlight part.

[@lompact3559]

Never been a fan of pigeon, but anything that is prepared is such an earth friendly way is worth trying.

[@WickedFalsehood]

they technically accounted for it but their simulations showed only a few degrees gain for the peak hours, so their simulations were heavily flawed but not missing

[@NightEye87]

Because the sun moves about in the sky. So you'd have to constantly change the position of the solar panels. In Spain they have a different way of tackling this (look up solar tower spain).

[@Omar-Vlad]

I'm fairly certain they were referring to the plastic parts of the car i.e. parts of the steering wheel, the dashboards, maybe parts of the engine. Of course the car itself didn't completely melt since metal has a very high melting point.

[@ShamelessHorse]

So why are solar panels flat? Wouldn't it be cheaper to focus the light with a concave mirror onto a smaller solar panel?

[@cpovey1]

I don't know about a test, but Adam has already made a Facebook posting about it!

[@cristianfcao]

Please Brady, do a video about the delayed choice quantum eraser experiment!!!!

[@michaelgreene9889]

Setting the bbq'ed pigeon aside, is there anything the building owners can do to mitigate the reflection?

[@CalebdGM]

According to wolframalpha, the pressure at the center of the earth is (1.35×10^8 to 3.68×10^8) kPa (kilopascals), a little more than a million atmospheres(!?!)... I'll check wikipedia... Wow, yeah, wiki says 3 mil. atmospheres, that's pretty crazy

[@tobywilson]

I'd heard the BBQ pigeon story before! I never knew my old professor started it though...

[@CicerotheDefender]

Of course due to wave/particle duality.

[@TheTlotra]

Thats a really interesting idea, this was an accident of design, but imagine a deliberate,thoughtful approach, you'd just need to make sure you don't cook the panels too much.

[@Kaitozas]

the building is concentrating light to a line not to a poin so it would be more dificult to pull that off

[@ChrisTheGregory]

Given that the normal is perpendicular to the surface, wouldn't that amount to the same thing?

[@Tyveris]

Could you build solar panels that could absorb more light at a time so that when buildings like this are constructed we could actually absorb all of that focused light instead of coating the whole side of the building in panels?

[@Mic_Glow]

Scientist: sculpture might hurt pidgeons. News: DEATH STAR IS REAL, SUPER POWERFUL DEATH RAY INVENTED

[@15brooksa]

Could this be used to increase solar panels power production?

[@BorealSelfReliance]

This is amazingly interesting... AND I wonder if the designer of that building got any flack for this...

[@willradley4039]

It's funny, because my mother is working on this building as a surveyor and she did mention to me that this could be a possibility.