Don’t Listen to YouTube Scientists - Safety Third 83 

As a 4th year engineering undergrad, this is exactly the misinformation I need right now. Thank you.

I am learning so much from these comments 😳

Talking about stuff you aren’t an expert on is GENIUS. Everyone is going to correct you in the comments, and engagement goes through the roof. These guys are RU-vid GODS, even if it’s unintentionally.

25:56 Me. I am the one you are giving an aneurism. Tbf most stuff was pretty close, and Kevin was spot on about Eddy Currents in AC. UHVDC is great for long distance transmission since there are no Eddy losses, meaning the entire cross section carries charge. It’s also why they use hollow tube for busswork in substations. The center of a solid conductor with a large enough diameter for the current required would be widely unused.

they removed the extra chair :( my hopes for seeing Nigel in this dumpster is all gone

this episode was extra painful to watch as someone in eee because it clearly is just magic. That's it.

This was in equal measure beyond interesting and frustrating.

I’ve never been more surprised to see a science podcast talk about science

Nigel will be such a great guest for this episode))

This is where I remember that RU-vid engineer is different than RU-vid scientist

This is how i explain NA home power: Three wires come to your house from the power station. The first wire carries an oscillating voltage that goes from -170v to 170v (which is 120v RMS) at 60 Hz relative to the third wire. The second wire also carries -170v to 170v relative to the third wire (120v RMS), but with 180 degree phase offset. The third wire is called neutral because it is used to reference the first two wires. If you look at the voltage of the first wire relative to the second wire (instead of the neutral third) you get a full 240v RMS at 60 Hz. This is all because the three wires are literally three taps on the transformer 120v apart. Now at your house in your circuit breaker panel, you can wire up 120v circuits by going from the first or second wire to the third. Or you can make a 240v circuit by connecting to the first and second wires only. Your third wire, at your house's breaker panel, will be connected to a giant, beefy bare copper grounding wire, which will literally be shoved into the dirt. This is basically for safety. Under normal conditions, current won't flow along the grounding wire into the dirt because the path along the neutral line back to the power station will be much MUCH less resistance. The fact that your panel in your house actually has two hot lines that are 180 degrees out of phase throws off most people i think because they see three lines and assume its the same three lines at your 120v wall outlet. its not! Your 120v wall outlet is connected to EITHER the first wire OR the second wire (but not both) of the main power supply to your house, and then the neutral line. and the ground pin in the wall outlet just connects to the neutral line as well at the breaker. This is why you can "trick" grounded devices by using old style ground to non-ground plug adapters, and then just not ground the adapter. the device doesn't know or care that its not actually grounded (for the most part). some fancier devices actually check if your ground pin is connected to neutral and will freak out if its not connected. I have a good UPS that will freak out if the hot and neutral are swapped or if ground is not connected. and yes, you can actually swap hot and neutral on your 120v wall outlet and most devices will work just fine. this can be incredibly dangerous though because some devices (like corded drills) will have a metal case and will put the switch on what it thinks is the hot line. this means parts of your device could be powered when you think they aren't and it can shock the piss out of you.

This is the episode where it would have been really handy to have Nikola Tesla as a guest.

I felt dumber after listening to this because I realized I couldn't concisely articulate how wrong everything was.

man nigel might’ve been a perfect guest for the static electricity part because what they misunderstand is all about how chemical bonds work (which unlike with how its usually taught through ionic bonding, is a lot less rigid than you’d think. especially with metals. metals are basically just surrounded by a soup of a bunch of the electrons so are way more chill with having some of them leave or added on extra)

a jammer is equivalent to a small child screaming at the top of their lungs to be as disruptive as they can because they're mad, making it impossible for anyone else to have a conversation.

Allen needs to rewatch technology connections. Alec answers so many of these questions very well. Maybe he should be a guest here some day

You need AlphaPheonix on the show! This woulda been the perfect conversation. Check out one of his recent videos on a better water analogy for electricity. What stood out to me is that the electrons we are seeing move and make power are equivalent to a ripple a few inches tall on top of an ocean as deep as the orbit of Neptune. There are a lot of electrons in a wire, and only a few of them moving does the work we get from wires. Also, none of the analogies work for high frequency AC.

I'm a screaming dude now with the radio wave thing. When RF waves pass by an antenna they change the charge of the aerials. This causes charges to move to each side, creating a voltage difference. The charge on the antenna is related to the size of antenna to wave length. You want crest of the wave to be on 1 side and the trough of the wave on the other. Wave length is v/f. Cut that in half for a dipole, and again for a 1/4wave. Have the radio detect the changes in the voltage and amplify it to a speaker

I love listening to 3 guys discuss their loads

PLEASE have technology connections as a guest omg

This reminds me of so many 3 AM study sessions back at university while getting my EE degree. Thanks guys for bringing back good memories.

the transfer of charges through contact is called the triboelectric effect, and yes electrons do move, thus making ions on either side. It's just that electrons moving isn't as big of a deal as Allen puts it, since relatively few charges are actually displaced from one surface to the other. The static zap is just the result of accumulating too many charges whilst being isolated, and suddenly discharging them using your body as one end of a capacitor.

my favorite four members of Safety Third are William, Kevin, Allen, and empty chair!

Like how you guys manage to talk about Chemistry everytime Nigel is out of town

My brain is having a hard time dealing with having more than 1 episode per month.

Most frustrating episode yet, keep it up

Nigel was great in this episode, he spoke as much as usual!

Man I really wish they would get that popular RU-vidr Nile red on. One day they might have the outreach

You can create light by accelerating a charge. There's a good 3B1B video (barbershop pole 2) that visualizes this. I come from the physics side, not the EE side, so I've always imagined a radio antenna as a dipole charge vibrating up and down. You can derive equations for how these vibrations depend on the amplitude, frequency, and distance between the two charges. It makes a lot more sense to think of the light as EM waves and then imagine you see the signal on an oscilloscope

I miss the zoom call with Nigel every time

46:50 ... FM works by measuring the distance from the central carrier in frequency and the distance is the amplitude of the audio waveform. AM works by transmitting a carrier and changing the intensity of the carrier to match the waveform (both need AGC to be nice and clean).

Heating things up is shaking them really fast, isn't it?

It makes me feel good to know that there are other people with engineering degrees (William and Allen) who struggle to understand or explain what are supposed to be the basic principles of physics. Most of what was discussed in this episode, I feel was covered in my Physics 1202 course in college, which, at least from a mechanical engineer's standpoint, still seemed like black magic. The mechanical analogy doesn't always translate well. This isn't a dig at William, Allen, or Kevin. If you don't study and apply this knowledge regularly, you lose it. Their youtube projects probably don't require most of what they learned in college. I'm waiting the the angry physics professor in the comments to correct them.

This podcast made me feel better about not knowing shit.

This is my favorite episode by far. Just some guys asking questions and trying to figure out how stuff works. I am always asking my friends these kinds of questions and they always say stuff like who cares, and doesnt really matter. I DON'T CARE THAT IT DOESN'T MATTER, I WANT TO KNOW!

25:29 the reason DC was hard at first is they had no way to boost or buck it. Whereas with AC it wasn't long before they had transformers that could boost the voltage into the 10s of 1000s of volts. AC is worse than DC at the same voltage because of the skin effect.

About the voltage cross highjack thingy, that's how internet in my house is transmitted, you need an modulator and receptor on each end, but essentially yeah it highjacks and very subtly modulates your AC to transmit internet at pretty decent speeds (50-100 mbps)

I’m not even an electrical engineer, but I was that guy that was getting frustrated haha. (Computer engineering degree and work in software dev). Also, true, there isn’t one guy who can understand all of the science and technology, but this episode covered simple enough topics that many of us do understand it haha

A great guest for this podcast would be nilered

a projector using an lcd needs two fresnel lenses , one on each side of the screen, to straighten and then cone the light ,and a focal lens to reverse and focus the cone out from the projector. I used to make these back in the day

We need an actual scientist to react to this and explain everything to us

Electronic is actually black magic, we live in a simulation. Now I feel good about my fail physic class

As someone working with bluetooth and wifi, i can tell you the main reason why bluetooth is used over over wifi in some instances, and that is power consumption. wifi power consumption is huge compared to bluetooth, the latency is being adressed with newer devices coming out with that support "LE audio", The problem with latency of legacy devices comes from the fact that there is no limit in the specification for latency of media content as it was designed primarily for music content. Voice calls and stuff do have a limit to the latency though, but is limited in audio quality. Bluetooth speakers particularly buffers up quite alot of data before it starts playing in order to extend range without gaps in the audio. more buffer means more reliable audio. And if you want to play your speaker at max volume in a busy metro you better have a loong buffer.

@40:30 "you can make a long wave length but just shaking the wire?" Well, yes. And you would be able to hear it, *whish whish* or *whoosh whoosh* depending on the thickness of the wire. (audio waves) Apologies to that one guy. ♥

The reason for the holes in the plugs is that they use them to hold the unfinished plugs in place while they put the insulation on Some factories that do it differently will have no holes on the plug

Excited for the Safety Third Safety Chair already

The microwave in my parents house absolutely knocks out wifi on the first floor especially for the tv, also my phone refuses to load anything online when I’m within 5 feet of the smart thermostat which I think is constantly trying to find other nodes around the house but we don’t have any so it just keeps blasting out signals

I have two basic stamp microcontrollers. They actually came with breakout and prototype boards that had standard FTDI USB-serial adapters, and the "IDE" software still runs on windows just fine. The crummier one came with the "Boe-Bot" kit for like $250, and is sitting right next to me. It was actually a fun little kit for me to learn some very basic "Blink an LED" style microcontroller stuff, especially for someone more interested in computer programming. The micro had a 20mhz processor, running an interpreted language called PBASIC, and had powerful built in support for I2C protocols and other absolutely essential things. They could directly drive servos for example. They were very good little gadgets and you can still buy them today! The $50 ones have 32 BYTES of RAM, and some of that gets reserved for I/O! Not bad for 2006

19:01 I know why, it’s to put suitcases locks 🔒 through the holes so people can’t use the device. Well that’s what my mom did to the tv when we were kids.

An antenna has electrons resonating up and down. Charge builds up at one point and creates an electric field. Then the charge moves to the other side of the antenna and that current creates a magnet field that is 90 degrees out of phase of the electrical field.

This has been one of my favorite episodes. ❤

you know it'll be a great day when you get a safety third notification

Nikola Tesla spinning in his grave so fast, only he could calculate the electron loss 😂😂😂😂😂

Y’all just need ham radio. Sincerely, a ham and RF engineer who has to be the one guy doing a dozen people’s work. I’m beside myself at the bumbling through RF physics 🤣 In fact I literally ran into Kevin at a hamfest looking for junk to probably make a spark gap lol.

3rd year mechanical engineering student here, interestingly enough the mechanical analogy for electrical circuits and vice verse that will mentioned is part of our syllabus, maybe a new addition if will didnt study it during his time at college

The way I always saw ground was: Everthing "should" go from positive to negative fallowing the circuit, but if it doesn't hopefully it take the ground you made, because either way it's finding a ground. Essentially if somthing goes wrong you want the least resistance to be through the insulated cords third pin rather then the hosing and out. (through you or other things)

In response to Will at about 9:00 I had the "Electronic Playground" (likely what you were talking about) when I was 9 or 10 and I loved the logic gates on it. I figured out how to build some crazy stuff with those and the 7 segment display. Never really understood how the transformer worked though, because it was always used with the speaker and all of those circuits were black magic.

this is the only podcast i’ve heard where i simultaneously feel smarter and dumber at the same time. thanks!

This is one of my favorite episodes ❤

I love this format. Three smart, moderately educated people discussing the borders of their understanding. This is how science would start if you would be interested enough to actually try to find out the answers of all the questions you speculated about.

14:10 I have to agree with Allen with this. I have LOST MY FUCKING MIND trying to find intermediate research on astrophysics and geology because the only stuff I can find is a website for explaining a topic to children and full blown research papers full of technical jargon.

Listening to smart people who don't have direct knowledge of a subject try to explain it to each other is deceptively funny. Their could be a whole genre of this. "A rocket scientist and a molecular biologist try to explain how to perform a minor surgery" or "a brain surgeon and a linguist explain climate change." Just very smart people with only tangential knowledge, frustrated but interested.

@16:42 "that's the one guy we pissed off" that was a good one

the temptation to write the paragraph long comment is strong

What is heating up something if not shaking really fast?

Radio towers are the same as infrared leds. LEDs are resonate thanks to the internal chemistry of the diode, but radios have to use conductors to achieve the same thing. The signal is just messing with the power going to the LED, but it doesn't change the resonance or infrared wavelength of the LED.

I love y’all’s podcast. I watch all your channels as is, but when the boys get together. Nerdy magic happens 🙌🏼😂

This takes me back to Communications systems course. AM got it, FM ok, QAM constellations . . . . . yeah its magic summoning circles or something.

As a licensed electrician I'd like to say your explanation of grounding and GFCIs was spot on.

14:43 - High voltage gets even stranger at higher frequencies.. Edit; An old friend/mentor who was a radio tech was once explaining various radio and RF things to me,and simply told me that "FM stands for F.....g Magic".

The high power broadcast rattling pans in the early days was from weak receivers. Between 1926 and 1940 receivers increased in sensitivity by a few magnitudes. DeForest probably just invented a couple new vacuum tubes or something to account for it. He wrote enough books to answer everything. He sold little volumes by subject in home classes in radios and electronics. Something like a vintage copy of Amateur Radio Operator is about the equivalent in one book without starting with 101. You should see my Japanese military crystal radio.

@1:08:26 I used to use an insulin pump that used IR to update from my computer. super unreliable especially if you had candles burning...

Lets get Jeff Gerling's Dad on here he can explain Radio waves and towers to you lol

I think dance dance revolution is a perfect analogy for Alan for frequency modulation. See you have the arrows coming down Which can come faster, or slower, but then you have different directions as well. So while each arrow is fixed when it enters the screen, there is a constant stream of different arrows coming down, and when you combine them all together, that makes a dance. Much like sending a signal via RF

Ground and neutral are tied together at the main breaker box (required by the electrical code). And every house has at least one big copper spike plunged into ground, so over the whole grid we've tied ground and neutral to dirt everywhere. But because the current alternates, and because we use 2 opposing phases of alternating current, most electrons don't move very far, and very little current flows back over the neutral out of your house (the neutral at a single phase outlet carries as much current as the live wire, but because other outlets are on the other phase it balances out, usually). 3 phase works the same way, in that very little power travels over the neutral unless there's an imbalance in the phases.

No power is transmitted through ground... You have 3 power lines, and transformers that go between two of those 120° apart create one AC phase with the neutral and ground attached to the middle of the secondary transformer coil, all the power goes back through the neutral to the transformer which gets it from the 120° apart phases. You can use it without a ground, but then if the transformer fails short across the primary to secondary you have thousands of volts in your home wiring. With a ground it should pop an overcirrent device immediately.

In hospitals or places with metal plates around their outlets it is very common for the fixture to be upside down because if the fixture's plate came loose and fell off it would fall and short the plug across live and neutral. NEMA (who develops the standard for american outlets) and CEC (Canadian Electrical Code) both say the outlets. Can go in either orientation there is no right side up. However, manufacturers often print on them in the common orientation which makes some people believe there is a "right" side-up

My recycled material shoes have this felt soaked in rubber soles. When new, the bottom was basically felt. For a month I was throwing large enough sparks to leave pin point burns on my fingertips. Yelped F! in a store touching the counter loud enough that 20 people stopped and swung around spooked. Didn't say anything. Doubt they'd believe it was bright enough to see. You can figure voltage by what each inch needs to reach breakdown voltage in air. They were 3/4th of an inch max. I think.... I think it is somewhere in the neighborhood of 15kv, if an inch is 22kv (don't quote me, it is probably wrong but ballpark).

The light programmable chips are in some 80's to early 90's slot machine motherboards. I might have some, not all the boards sold on ebay.

The coils of wire in a transformer produce an magnetic field, transferring electrons to the other coil, but without an iron core it does it very inefficient. Because of this there is iron core is made out of thin metal sheets because the skin affect, so the noise you hear from the transformer it’s actually the laminations of metal not the wire. 40:07

Ground (for you appliances and house) is for non current carrying metal objects. It is for protection. Your neutral is tied in with the ground at your panel. The earth just acts as a big resistor. Just soaks up energy and radiates it out as heat.

You guys were so close but so far on so many subjects hahaha love it

I actually got Nintendo Labo. It was really cool for what it was. You could program them and make your own little games to play, and I programmed Bop It and even won an official contest and won one of the other Nintendo Labo sets. So I was the one in a thousand kids that did the insane customization. I made a mario pinball machine too with an indepth scoring system with like multipliers and a "boss fight." I still use it sometimes for the mario kart controls. The mario kart controls are INSANELY poorly optimized sadly but it's fun making your friends play with the awful controls and try to beat the AI.

Another week another banger episode.

Bluetooth has lower power so battery powered devices can use it, and it uses lower data rates for the same reason, and it has less authentication and supports fewer connections because it's intended to be a persona area network, so you need to be close by.

It's incredible how invested I am over a conversation of concepts that I have zero understanding in. It's like hitting some part of my brain that I'm not even aware of.

The thing a Van de Graaf generator is named for is the bell which acts as a Faraday cage. Like charges repel eachother from the inner surface. The triboelectric belt is sort of like the windings in a Tesla coil, easy to fixate on, but not the clever part of the device.

@26:20 the reason is because if an electrical or other conductive unit(piece of metal) has a different earth potential than the circuit it's on, you get zapped. By law in my country (Norway) the least amout of touchable voltage that is "allowed" is 50VAC or 100VDC. So that's why it's very important to not separate earth connections. Example: Your plumbing is connected to earth, your circuit to your bathroom has faulty earth, caretaker want to dry her hair, while holding the dryer and touching metal piece on said dryer, she puts her other hand on the sink/tap (why? because humans does these things.) now caretaker gets blasted with faulty earth potential from arm to arm, electrocuting her through the heart (the heart doesn't like 50/60Hz). Keep in mind that a human being can withstand 30mA for 0,5 seconds without any damage, anything beyond that you can get seriously injured. Typically your wall outlet is 10-16A.

I love how Allen is just asking all the questions we all have! This whole discussion is how my brain internally tries to reconcile human existence.

I wish more episodes were like this, really makes you think and reassess your knowledge. Also, Bluetooth and wifi are basically the same thing, thats also why they use the same chip and antenna on your phone. But Bluetooth is simply using less power to achieve a similar but scaled down result. I have been advocating for 5gh wifi headphones for years now, it would solve most of the issues current models have. Unfortunately, battery time is more important than quality for most people.

Questions like the static electricity question popping into my head at bedtime and access to the internet are the reason that I don’t get enough sleep.

At the primary side of the transformer the ground does conduct all the current. Because the earth is so big, the cross sectional area is huge and the resistance is low. The closest substation to your house has hundreds of ground stakes to complete the circuit. Inside your house there is actually a neutral conductor back to the secondary of the transformer so there shouldn't be any current unless the hot wire finds a path to earth.

This has to be my favorite episode yet.

Oh god. 3phase Delta never references ground, but a ground path does exist. However inside of a residential transformer the neutral is a center tap that split the full coil thus giving you the split phase 120/240. We tie this to ground giving you a true neutral reference point. The equipment ground is there for safety so that if something goes wrong it will take the low resistance path to the panel and trip the breaker

It’s so easy to forget that you guys are actual scientists, then every now and then we get something like this

This episode makes me feel way better absolutely tanking the electromagnetic fields portion of my engineering physics class when I was in college

I can sorta answer the bluetooth point! Bluetooth requires a specific codecs for sound/music to be sent from one device to another. So it needs to be packaged at one end, sent across time and space, then decoded at another. To make it more efficient, quality is lost. If you are looking for high quality audio, cable is the way to go. If you're not fussed, get bluetooth. I'm honestly suprised everytime I get to use obscure elements of my first degree.

One of my best friends is a radio scientist, He builds simulation tools to test radio propagation over land. ive had him explain how information is sent wirelessly many of times, and after hours of drawings and explanation i can confidently say it still makes very little sense. i can see if he would want to enplane it on your pod i can ask.

If you have the plug upside down the ground prong is the first to come out of the socket. Then you have a potentially live appliance with no/weak ground. But the reverse is true if something is dropped in it hits the hot prongs first. (Like you said) As far as I know there is no code requirement to do it one way or the other. You can even put the plug sideways (think hospitals).

Guys I get so excited when I see one of their faces on a blue background pop up in my notifications 😂