I still don't understand the design of the white kettle. Help me! Also, I still don't know why the 40:60 vodka boiled for longer than either water on ethanol on its own. Something to do with heat capacity maybe. The sponsor is Curiosity Stream: Get a whole year for just $14.99 curiositystream.com/stevemould

@jonny__b

2 жыл бұрын

Think you've got a typo there Steve - while ≠ white

@miscellaneous3.0

2 жыл бұрын

maybe the white kettle works by temperature difference/gradient

@LawTaranis

2 жыл бұрын

The thermal switch is indeed a safety in case the kettle is dry. It interrupts the circuit once it reaches a set temperature, which is usually stamped on the metal casing. It probably is set to 150C.

@augustblanco7831

2 жыл бұрын

The metalic strip is not in the buttom. the one in your video is not the switch. it is the safety feature where it cuts off if the kettle runs dry. the original metalic switch is on the side of the kettle. try disassembling the handle and you will see what I mean.

@6regmcc

2 жыл бұрын

I don't know how it works but ALL KETTLES will keep boiling unless the lid is on.

This demonstrates exactly why forming a hypothesis and then doing the experiment is so important. I was just as confident as you were what the likely results would be, and was equally as wrong. Looking at the length of the video, I knew there must be a catch, but without that context, I would have been just as surprised!

@ThatSoddingGamer

2 жыл бұрын

Yeah, I had the same assumption with the second kettle after it boiled; I assumed that it had to do with water's greater heat capacity, so the base would just heat up faster than the ethanol could expel it, and it would be set off anyway, so the device doesn't care what is in the kettle, just how hot the base is. Turns out it was that small hole easily overlooked in the design. Actually, I wonder if he tested to see what happened if he did let it boil dry? He said it kept boiling, but didn't clarify whether he let it boil dry. He could have stopped it after it kept boiling much longer than his previous test. The idea that it's a safety feature in the event that the liquid boils off before the buildup of steam is enough to trigger the bimetallic switch is a good one and would explain why they went to the trouble of applying the thermal paste. It might just need a higher temperature than it can reach when there is a substance with enough thermal conductivity to prevent it from hitting a certain critical temperature.

@pafu015

2 жыл бұрын

Doing an experiment first and then deducting also works.

@kiraPh1234k

2 жыл бұрын

Lol, the whole time I knew he was wrong but I thought the method was funny. Like, you didn't need to set up an experiment even. Just do a little work on research first and understand the problem. For example, if you understand your question is about an electric kettle's operation - then instantly you know that we are talking about specific engineering. We also can understand the problem space (boiling) and how to test for boiling (which you cannot use temperature for unless you have a measure of pressure as well). So when he kept talking about his first assumptions and "hypothesis" (in quoted because to be honest a genuine hypothesis would go through the research/education phase before there's any reason to test), my brain just kept yelling "But you don't understand how the kettle works, or even the problem space". As he eventually mentioned, his hypothesis, if correct, would result in a kettle that doesn't work on mountains and that's not a reasonable conclusion for a well understood problem. Had he asked himself first "How can I tell if water is boiling?" Then he may have realized he couldn't use temperature without also using pressure. That pressure also needs to be measured inside the kettle rather than outside which is also another challenge. Sorry for long post, my point is just that I think that this demonstrates the need to follow proper methodology in forming your initial hypothesis rather than treat it as a "guess and check". There is a stark contrast between "guess and check" vs "educate, guess based on that education and check"

@robertmaske2030

2 жыл бұрын

@@kiraPh1234k Researching how a kettle works and then just presenting this 'secondary' knowledge would be way less entertaining for the viewers and less effective and so less people would be a bit smarter after the video. What steve does here, is just demonstrating the scientific method.

@ImTHECarlos98

2 жыл бұрын

@@kiraPh1234k You could use temperature without pressure, if you make it turn off when the kettle maintains a specific temperature for a given amount of time. This would work anywhere.

I recently turned my kettle on and went to the bathroom, expecting it to turn off. When I came back it was still on and there was a strong burning smell. I went to turn it off and almost burned my finger on the switch. So I bought a new kettle. That's my anti-climactic story of the day.

@boRegah

2 жыл бұрын

I loled. Thank you

@pvic6959

2 жыл бұрын

im happy it was anti climatic! otherwise your house would have burned down and THAT would be bad! glad you're safe!

@E.T.S.

2 жыл бұрын

These things should not happen. If it were fairly new I would inform the shop. There could be something wrong with an entire batch.

@skussy69

2 жыл бұрын

@@pvic6959 would have made for a better, non-anticlimactic story though. It goes both ways

@pansepot1490

2 жыл бұрын

Wouldn’t it have been safer to just unplug the hot kettle? Instead of risking the finger on the hot switch?

sad to see he wasn't doing multiple "taste tests", would be fun to see a progressively more hammered steve mould do science.

@NobleNobbler

Жыл бұрын

lol

@ghans2305

Жыл бұрын

That would be hilarious

@sohankatragadda4301

Жыл бұрын

The second liqiud was probably denatured alcohol, so he prolly would have gone blind if he had taste tests

@IoEstasCedonta

11 ай бұрын

Do they sell Everclear in the UK?

@gilgosseyn6602

7 ай бұрын

Gotta give it a little nibble after opening the bottle, just to make sure it's not fake... or something...

They say admitting that you're wrong about something is hard, but this video shows it's actually super easy, barely an inconvenience!

@hellodude8794

7 ай бұрын

How did pitch meeting get into here

@phil2782

7 ай бұрын

I used to love Ryan George, I still do, but I used to too.

@deadskimountaineer

6 ай бұрын

Oh really!

@chrism3784

6 ай бұрын

wowowowowow

@christophergallagher3721

5 ай бұрын

Non sequitur references are TIGHT

I love that what was initially a physics/chemistry experiment turned into a deep dive into kettleology.

@dametocosita4994

2 жыл бұрын

Welcome to Vsauce

@squatchjosh1131

2 жыл бұрын

@@dametocosita4994 Michael here

@pomonoli

2 жыл бұрын

kettology

@Swyse

2 жыл бұрын

Honestly that's why I clicked initially. I wanted to know how kettles work.

@decryptingelectrons

2 жыл бұрын

Colin Furze needs to weigh in

the thermal contact must be for emergency thermal runaway. When the kettle is dry that heating element will melt itself and the kettle. No way those plastic parts would hold up. Must use the steam as the primary, and the contact one for runaway. This finally makes sense why my kettle wouldn't shut off on it's own with the lid open a crack. I'd been wondering that for years!

@Catastropheshe

2 жыл бұрын

"and cracked" 😂😂😂

@KillerDragon987

2 жыл бұрын

@@Catastropheshe reading is quite a challenge for some it seems

@Catastropheshe

2 жыл бұрын

@@KillerDragon987 ?

@Michael-kp4bd

2 жыл бұрын

@@Catastropheshe the commenter talked about what happened when they kept their kettle “open a crack” (a little bit) You seemed to misread it as though they said that they kept the lid open, and then it cracked. It’s funny you put it in quotes, because those words are not in the comment. No sweat, i misread stuff all the time. But I do try to make sure i quote people correctly 😄

@Michael-kp4bd

2 жыл бұрын

Although I must admit, quoting someone on KZread is sometimes hard on mobile, because your text box takes over the screen, and if you try to move through the comments to read as you write, it asks you to discard your comment 🙄

This is why you need teams of full-time engineers to make stuff like kettles.

@sauschwaenzleklan

Жыл бұрын

Werner von Braun once said: 1000 hypothesises cannot beat one experiment

@KainRazielMT

Жыл бұрын

A kettle is one of the simplest electronic devices known to manking. Don't talk about shit you don't understand.

@alwaystired1

Жыл бұрын

@@KainRazielMT who hurt you

@nfsdude0125

Жыл бұрын

@@KainRazielMT You are factually incorrect, well done! Dunning-Kruger scale at work once again.

@mmww7243

Жыл бұрын

@@KainRazielMT i thought so before taking a thermodynamics course 💀

I wish more videos were like this on KZread. Seeing the thought process and “failures” in understanding the construction is really quite pedagogic. The absolute best way to teach your audience. Great job my good sir. Hoping for more videos like this. Also takes courage to admit your hypothesis was wrong

@uzetaab

Жыл бұрын

This video reminded me a lot of technology connections. Try his toaster and washing machine videos. Really great. www.youtube.com/@TechnologyConnections

@uzetaab

Жыл бұрын

Sorry, dishwasher, not washing machine

@treali

2 ай бұрын

I think he kind of ruining the message by pre-phasing saying "I am usually never wrong". If you actually go out of your comfort zone in science you will have many wrong hypotheses. It also doesn't require much courage when the stakes are low like in this experiment.

@AK-jb8hs

2 ай бұрын

​@@trealidoesn't necessarily mean he always has to be wrong lmao.

@treali

2 ай бұрын

@@AK-jb8hs Don't know what mental gymnastics you did to come up with that sentence. I blame the loss of ability to think in other ways than just black and white.

The sensor with the thermal grease is called a resettable thermal fuse or thermal cutout switch. They are used for safety reasons for when a heating element/control circuit goes out of control. They usually have quite a high temperature rating before they switch, and don't have a very good cycle life (you wouldn't want to rely on it switching every day in a product). You can find exactly the same style ones in things like space heaters, microwaves, etc.

@niklas6576

2 жыл бұрын

So there would've another component in the kettle to sense the heat of the steam? And Steve missed it?

@listerdave1240

2 жыл бұрын

@@niklas6576 Yes, see my post earlier. The white kettle works exactly same way as the transparent one. It is just less obvious where the bimetallic strip is.

@halonothing1

2 жыл бұрын

lol I didn't find anything like this in the space heater I got that almost started a fire. It was a refurbished one, but was bought legally from a legit brick and mortar store here in Canada. So you wouldn't expect anything untoward. But I was using it in the dark one night and noticed this red light inside it and initially just figured it was a red LED, even though I didn't remember there being one inside the heater. But a minute or so later it went from red to bright white and I realized something in there was getting way too hot and turned it off etc and cut off the plug so nobody accidentally uses it. Which a lot of people don't think to do but it's good practice. Anyways, I took it apart a few days later and found the source of the overheating was an improperly crimped (and probably underrated) spade connector that had literally melted from the heat. The really scary thing is because of where it happened, there's no way I would have seen it if I hadn't looked at it from just the right angle. And it was so dim that if the room was lit up, I never would have noticed. So I probably wouldn't have noticed anything until shit hit the fan. I don't know why, but I didn't bother reporting it. I think I was just so pissed, I was done with it. But in retrospect, I feel negligent because it was my responsibility to at least let them know so the product can be taken off the shelves in case it happens to somebody else. Or at least they could actually inspect the work of whomever's in charge of refurbishing them. Live and learn, I guess.

@MrPaw45

2 жыл бұрын

It's boil-dry protection I believe

@LaggerSVK

2 жыл бұрын

Makes complete sense. The sensor on plate just protects the assembly for overtemperature if someone left kettle switched on without medium. The bimetallic switch with steam bypass is the thing that regulates the temperature.

I used to work for Salter, and assessed a lot of kettles similar to these. The secondary thermostat is indeed a safety failsafe, to prevent a fire in case the primary temperature controlling thermostat does not activate - it's typically set slightly above the normal operating temperature range, so it would only switch if the kettle is heating up uncontrollably. Inclusion of these failsafes is a requirement of the Low Voltage Directive - if you're curious, the standard EN 60335 goes in to some detail about what's required.

@TomasBenes83

2 жыл бұрын

Weren't you experimenting with switch-off accuracy? It always annoys me lot when a kettle doesn't turn off when reaching the boiling point. It takes typically more second longer to it. So I wondered why not to involve vibration and noise sensors to it (except of course price, complicated complexity etc.).

@_APV_

2 жыл бұрын

@@TomasBenes83 Noise sensor wouldn't work, as music/tv/speaking would trip it, and to filter out all the noises would require some complicated tech. Vibration sensor sounds like an interesting idea, shouldn't be too expensive, you can easily prevent it from being triggered by a random touch or momentary shock, by coupling it with a 1s delay. It would trigger if there's some heavy machinery working nearby, which is sub-optimal...

@TomasBenes83

2 жыл бұрын

@@_APV_ I mean it should be easy for machine learning to surely recognise boiling sounds from beneath the kettle's inside, despite of surrounding voice. In combination with other aspects of course. Not only vibrations. Atmospheric pressure sensor is cheap. In combination with measurable water temperature and perhaps even outside temperature it should be easy to estimate exact time when to take other fancy inputs (certain sounds + vibration) into account. I can imagine stupidproof process diagram. I got Princess induction kettle for.. more than 100USD? It kind of sucked too, but in different aspects.

@cassandra2860

2 жыл бұрын

@@TomasBenes83 a kettle doesn't need AI.

@TomasBenes83

2 жыл бұрын

@@cassandra2860 thank you, captain obvious. We don't have AI, although it might be fun, guessing from RedDwarf''s toaster. But machine learning could be helpful to learn distinguished boiling sound from hundreds of environments and give the code then to kettle's chip.

I do think the thermocoupled sensor is for boil dry protection, try boiling that kettled with the lid open until empty and see if it switches off. The temperature setpoint for that is probably well above 100°, something that would only be hit with no thermal mass being heated

@MeteorMark

Жыл бұрын

I'm sure it is, as an apprentice I've worked on a new kettle design for use onboard commercial aircraft, besides boiling lots of water and doing temperature measurements, I also got to test the existing design to failure 😉 This had a thermal switch that detected the boiling coupled to the metal jug, heating element spiralled around the jug. When all water was boiling off, switch was just switching heater off and on more rapidly and just kept going without water. Then bridged the thermal switch to test the thermal fuse with a rating of (as I recollect) 120°C, so when kettle empty, this blew and prevented overheating. So bridged the fuse, and tested it till smoking hot, proving the thermal fuse they wanted to omit to reduce costs was necessary. I've never seen the Combi Kettle that was being designed in an aircraft, only once in the background of the Engineering Connections A380 episode with Richard Hammond.

@NicksStuff

Жыл бұрын

Simpler test: turn the kettle on when dry. Does the base heat up to over 100°C and the kettle switch off afterwards?

@gamegod36

Жыл бұрын

@@NicksStuff Dry boil protection 😂

@markoap91

8 ай бұрын

@@NicksStuff I'd say that's the best way to test it and it makes sense that it is a safety sensor to protect from thermal runaway when dry as the main shut-off mechanism cannot work if the kettle is dry and, without it, there would be nothing to shut it off or conduct away the heat leaving it to essentially catch fire. The thing is, we have accidentally tested this on our kettle when my girlfriend accidentally turned it on when it had nothing in it, it started to smell and I immediately noticed and turned it off, I did it quick enough and there was no damage but no safety kicked in leaving me to think that I was just quicker and the safety sensor just didn't have enough time to reach the temperature required to trip it. With that in mind, running a dry kettle to test the safety sensor is probably gonna damage it so only do on a kettle you're willing to lose.

@filanfyretracker

5 ай бұрын

@@MeteorMark its always amazing how companies will want to drop a 3 dollar safety system like a thermal fuse even for something that will go in a passenger airliner.

6:40 I've actually been using a kettle like that for several years, initially at about 5200 ft above sea level before moving closer to the coast. It was programmable to several temperatures, intended for different teas (e.g. 175°F for green tea, 190°F for herbal teas, 200+°F for black teas). I quickly found out that yes, it would boil dry if set to 212°F at that elevation, and 200°F worked a lot better for me, being a lot closer to boiling at that altitude. From the very start of the video I was saying to myself, "It depends on the kettle's shutoff mechanism..."

@godowskygodowsky1155

7 күн бұрын

I tried using a kettle in Denver. It just stayed on. Perhaps it didn't have this mechanism.

So here's a fun one: If you've ever seen one of those rice cookers that only has a single switch that pops up when the rice is done, those DO work the way you've hypothesized. The difference there is they're set _above_ 100 C. When all the water has either been absorbed or evaporated, the temperature is allowed to rise above that mark, and turn off the cooker via * a similar system using the curie point of a magnet, where the magnet will temporarily lose its magnet properties releasing the switch *. * edited *

@Mueller3D

2 жыл бұрын

Many rice cookers use a different temperature sensing mechanism based on a magnet's curie point. The magnet normally holds the contacts closed, but when heated above its curie point, it loses its magnetism and releases the contact. This is explained in more detail in kzread.info/dash/bejne/hIeIsMqvdKrIiaw.html

@wychowanek90

2 жыл бұрын

Allec from Technology Connections made a great video on the subject of rice cookers and curie point, I'd recommend watching it.

@piteoswaldo

2 жыл бұрын

@@Mueller3D But then the material would be demagnetized and need a high voltage coil to remagnetize it. Or it would only work once, then you'd need to replace the magnet. I've watched that Technology Connections video before, but I don't remember the details.

@dextmo6890

2 жыл бұрын

@@piteoswaldo No, curie points are a temperature where the metal becomes paramagnetic and requires a magnetic field to be magnetic, and once it cools down it becomes spontaneously magnetic once more. You don't need a poweful magnet, the material simply reorganizes itself to become magnetic once it becomes cool again.

@themasterone16

2 жыл бұрын

When I bought mine, I was curious of how it will stop buy himself. So, I put some water in it and tuned it on, and... It never stopped :D ! And then i search the info on the internet !

seeing someone say "damn, damn, i was wrong" with a huge smile on their face is so goddamned wholesome

@Verrisin

2 жыл бұрын

every smart person loves being wrong, UNLESS something important (like your salary, or happiness of your kid) depends on you being right...

@jezmy2006

2 жыл бұрын

Maybe you could ask Medhi for his views on what might be happening ? 😛

@antman7673

2 жыл бұрын

Being wrong is necessary if one believes in the concept of truth.

@Verrisin

2 жыл бұрын

@@antman7673 to be fair, the concept of truth is already a dubious notion... I would just say one aims for "more predictive models" rather than "truth". It will always be a simplification of reality, but some are more accurate than others. (and amusingly yet sadly, the most (evolutionarily) useful ones are often not the most accurate ones... and even in science, one often prefers models which are cheaper to compute, when the higher accuracy is not needed)

@BloculusMonster

2 жыл бұрын

now THAT'S science.

The "bimetallic" disc is usually shape memory metal these days. It has a snappier toggling action and works at a dependable temperature based on the exact alloy. The glass kettle probably has an extra one (or even 2 for extra safety, like mine) buried under the switch mechanism for the safety boil-dry cutoff, and maybe the white kettle has it's main sensor in the handle so is functionally identical to the glass one.

This was definitely the most interesting video I've seen on kettles! Fun to watch you do trial and error and come to conclusions. Subscribed!

@No_True_Scotsman

Жыл бұрын

Have you seen the channel Technology Connections? You might like it.

@asnovasdodia

Жыл бұрын

You should check @Technology Connections

@Krytyk15

6 ай бұрын

bruh, chech technology connections, he has kettles bruh

@gjingodjango

3 ай бұрын

…or get a life!

10:00: Easy answer: A few years ago, someone accidentally triggered the lever of the water cooker at my workplace. They didn't notice that, and the water cooker was turned on, without water inside. Apparently, that cooker didn't have the thermal coupling to the base and instead only relied on the steam. But if there's no water in there, there is no steam in it either. We noticed only a few hours later, when someone noticed the smell coming from the kitchen. Long story short: This cooker hat started to melt already and we were quite lucky that someone noticed it before everyone left the office that day.

@HappyBeezerStudios

2 жыл бұрын

my kettle tends to turn off a couple minutes after the water is gone. Which will happen when there was only little water in, as somehow the shutoff point is higher then the boiling point of water here (around 10-15m above sea level)

@brokenocci

2 жыл бұрын

i did open it without water in it and it exploded near my face i was very lucky lol

@gelo1238

2 жыл бұрын

The heaters usually have an additional thermal protection, but it will work at very high temperatures around 200C. Or they have?

@krashd

2 жыл бұрын

@@gelo1238 The second switch discussed in the video is the thermal protection, the sensor stuck directly to the underside of the element. It's only purpose is to shut off the element if the kettle is empty because it senses that the element is heating up too rapidly.

@7784000

2 жыл бұрын

Everything produces vapor if it becomes just hot enough.

I remember being a line cook, and sometimes people would want their soup even hotter than the temp we held it at. So I'd throw some in a pan and swirl it over heat until the soup boiled. I would always then say "well, it can't get any hotter than that" and so many people greeted that response with a confused look. It was weird, because it was always my assumption that boiling was as hot as a liquid could get (and all energy input thereafter went into the phase transition). Thanks for another great video steve.

@yomama3832

2 жыл бұрын

UNCENSORED S*X ASIANTEEN.SPACE 👆 Megan: "Hotter" Hopi: "Sweeter" Joonie: "Cooler" Yoongi: "Butter Asi con toy y sus mañas no se la lease que escriba bien mamon hay nomas pa ra reirse un rato y no estar triste y estresado.por la vida dura que se vive hoy . Köz karaş: ''Taŋ kaldım'' Erinder: ''Sezimdüü'' Jılmayuu: ''Tattuuraak'' Dene: ''Muzdak'' Jizn, kak krasivaya melodiya, tolko pesni pereputalis. Aç köz arstan Bul ukmuştuuday ısık kün bolçu, jana arstan abdan açka bolgon. Uyunan çıgıp, tigi jer-jerdi izdedi. Al kiçinekey koyondu gana taba algan. Al bir az oylonboy koyondu karmadı. ''Bul koyon menin kursagımdı toyguza albayt'' dep oylodu arstan. Arstan koyondu öltüröyün dep jatkanda, bir kiyik tigi tarapka çurkadı. Arstan aç köz bolup kaldı. Kiçine koyondu emes, çoŋ kiyikti jegen jakşı dep oylodu.#垃圾 Son unos de los mejores conciertos , no puede ir pero de tan solo verlos desde pantalla, se que estuvo sorprendente 💗❤️💌💘💟

@zarethd

2 жыл бұрын

You could always put it in a pressure cooker! Lol

@r0cketplumber

2 жыл бұрын

@@zarethd And as soon as you relieve the pressure the water will flash boil and cool right down to 100 C.

@palmereldritch6137

2 жыл бұрын

This was the basis for a student comedy short called Pendleton the cook, its on youtube somewhere. I never imagined it was a reality in the kitchen.

@slurpleslixie

2 жыл бұрын

​@@r0cketplumber So just pressurise the whole restaraunt :P Of course after this facetious comment I then had to go and do a quick research, and it seems like pressure cookers run at anything up to 2atm, and humans can apparently survive up to about 2.5 so in theory this should actually be possible ...

Thanks, I've always wondered how these work and enjoyed following along on this one!

I just recently discovered your channel. I'm a math guy, but I love your enthusiasm and you come up with such interesting experiments. It really opens the door to a wider world than just focusing on a narrower application. And this particular video really appealed to me because I have long wondered how my electric kettle knows when to turn off, and why it never turns off if I forget to put down the lid. This was wonderfully enlightening. So much wonder in a mere kitchen kettle. :-) Thank you.

I always thought it shuts off based on the vapor pressure in the kettle feeding back pushing something in the mechanics. Because if you keep the lead open the kettle won't shut off. But i guess now i see keeping the lid open the vapor won't go down the side tube to trigger the thermal switch! Can it be pressure as well somehow too?? Maybe the thermal sensor is for over heating protection, but there is also a hidden pressure sensor??

@xcix8150

2 жыл бұрын

I never thought about it like this

@chemicalBR0

2 жыл бұрын

you are on the right track but it's not based on pressure it's purely based on the boiling point of the water. 4:30 in the video shows it working , it is purely down to the warping of the metal disk that flips the switch (a bit like the popping seal button on a jar of jam or hot dogs) the reason they use this method (and not a thermostat or pressure) is that water boils at different temperatures depending on your altitude, water purity and pressure. (if you had a thermostat kettle set to turn off when the water reaches 100 degrees C and you tried to boil water at the top of mount Everest the water would boil long before hitting 100 degrees and the water would just boil away to nothing without ever hitting 100C) for every 150 meters you go above sea level the boiling point lowers by 0,5 degrees C. at the top of everest the boiling point of water is 68 degrees C. using the warping metal sensor it would still work even at this low temp because steam would still be produced when the water boils at 68 C and would still flip the switch (the flipping of the switch is not dependent on the temperature reaching 100 degrees it is purely dependent on when the water boils and produces steam) at the dead sea which is below sea level the boiling point is around 102 C (so a kettle with a thermostat set to 100C would turn the kettle off before the water is boiled) pressure has nothing to do with it , water under pressure has a higher boiling point than 100 degrees, this is how pressure cookers work, it cooks stuff quicker because the water under pressure is a higher temperature than 100 degrees, pressure cookers usually let water reach around 120 degrees C before it boils (kettles are not sealed so the pressure doesn't build up much) if a kettle was under pressure the water would boil at a temperature above 100C and that would be bad news if all you want to do is make a cup of tea. the higher up you go above sea level the lower the air pressure and therefore the lower temperature is needed to boil the water (high pressure= higher temp needed to reach boiling point, lower pressure = lower temp needed) the reason a kettle doesn't switch off with the lid open is that the steam escapes through the MUCh larger opening and does not travel down the tube to trip the metal disk. www.thermal-sensor.com/upfiles/13172138801INSERTING_KETTLE_THERMOSTAT_KSD300B.jpg (when the steam hits the metal it warps it and the strip in the centre of the disk flips the switch, as it cools the metal returns to its original shape and the switch is reset) it is simple and it is genius its not a temperature cutoff, its a boiling point cut off, it is not dependent on the temperature of the water, only whether it is boiling and producing steam which as I said before can change depending on your altitude above sea level (air pressure), the switch will always work when steam is produced regardless of the waters temperature or the air pressure.

@VovaMohammad

2 жыл бұрын

Same for me. And it explains why the handle gets quite hot on a lot of different models. This small thing on a bottom could be the emergency switch if you turn a cattle without water. Not 100% sure, just assume that.

@FantasticW7World

2 жыл бұрын

Hmh our Kettle still worked even though the lid was broken and there was a big hole in the middle. But it also was a fancy one with a temp sensor inside it

@jaysunbrady

2 жыл бұрын

*shut off not shot off. Also its keep the *lid open not keep the lean open. I suppose all those shocks have messed you up a bit.

Some simple rice cookers do something similar, they have a permanent magnet attached to a metal plate which opposes tension in a spring. During cooking the boiling action means the temperature stays largely constant. Once all the water has all been absorbed by the rice the temperature starts to rise and would cause the rice to burn, however, the rising temperature eventually destroys the paramagnetism of the metal strip causing it to detach from the permanent magnet, releasing the spring tension and shutting off the power. Very ingenious stuff for a simple appliance, it allows you to cook any amount of rice unattended as long as you get the water rice ratio correct in the first place.

@douglasburnside

2 жыл бұрын

_"...as long as you get the water rice ratio correct in the first place."_ Actually, the ratio can be anything you like as long as there is enough *or more* water than required for the rice. The excess water will continue to boil and leave the rice cooker as steam until what is left has been absorbed by the rice. At that point, the temperature will rise and turn off the rice cooker.

@aterack833

2 жыл бұрын

Rice cookers are the most ingenious design out there, popcorn moisture sensors is a close second

@swiftythegathering

2 жыл бұрын

Ah, a Technology Connections viewer as well?

@meikie

2 жыл бұрын

@@swiftythegathering this is exactly the comment I was looking for

@SensitiveSavage

2 жыл бұрын

It is amazing isn't it? There can also be a difference in the amount of water and rice added. Meaning you don't always have to get the ratio correct. I've had experiences where I thought the water was too much and yet the Rice Cooker prepared the rice perfectly. Clearly it was made with the intention of helping cook rice quick and easily, despite an incorrect ratio, and I am very grateful 🤣.

Wow! It is amazing that you can turn such mundane situations/objects into fascinating examples of scientific thinking. Keep up the good work!

Your videos are so good. Seemingly mildly interesting things turn out to be wildly fascinating.

Steve, all the electric kettles I have taken apart have two thermal switches. One attached to the heater element that prevents boiling dry, and another activated by the steam. On the white kettle the thermal switch you show at 7:13 is the boil dry switch (I reckon) and if you were to dig further you would find the other one. The Russel-Hobbs kettle also deserves further dismantling.

@giggletub

2 жыл бұрын

As it happens, youtube has a number of kettle teardown videos. James Henry's "Kettle secret" is a favourite.

@punkdigerati

2 жыл бұрын

I believe they are both Russel-Hobbs brand.

@seraphina985

2 жыл бұрын

Yes the black one almost certainly also has an equipment protection thermal cutout switch. It will be attached to the upper side of the switch assembly in contact with the metal base above it.

@Steve211Ucdhihifvshi

2 жыл бұрын

Mine has a microprocessor and you can set the temp. Say 55 degrees c, hits that temp and off.

@czibbell74

2 жыл бұрын

Yep. Similar to the photocopiers I used to work on, which had two devices - a thermistor to sense the temperature, and a thermal switch/fuse, exactly like the one in the white kettle, that would open when things got too hot, just as a safety device. I believe they were supposed to reset themselves, but they would sometimes fail to do so.

Both kettles are simple designs, that work with the "steam detection" method. As soon as steam or hot liquid touches a bimetallic switch they shut off. In the white kettle the bimetallic switch is hidden in the handle. The device on the heating plate in the white kettle is a security fuse. It will permanently cut the power if the kettle runs dry and the heating plate gets dangerously hot.

@elixerlucas4936

Жыл бұрын

This is accurately correct and that is the common design of electric kettles. Normally, the so called "vapor" was a steam which could be hotter than the temperature of a boiling water. The thermostat disc will actuate once the steam get a contact with it. This video is nonsense I thought it was a good one. Conducting experiment without a further knowledge on the equipment to be used for the test 😖

@jam99

Жыл бұрын

@@elixerlucas4936 Yep, it was all pretty obvious if you actually know how the control mechanisms were designed and where the transducers are. The practicalities are still interesting.

@hrgwea

Жыл бұрын

The key to understand it all is in the fact that the manual switch and the automatic switch are combined into a single component. This is what allows the manual switch to flip automatically. Since one kettle has the switch at the top, it only needs a hole at the top to conduct the vapor to the switch. Whereas the other needs a metal tube to conduct the vapor downwards where the switch is.

@Gegi1992

Жыл бұрын

Hello sir, I'm a bit late but you seem to have somewhat of an understanding of this so maybe you can answer this. When I watched the video, I thought that the Thermostat was the thing controlling the shut off and the little grey metal thing (you can see it jammed underneath the top screw at 8:28) was the safty feature. But after watching the video and reading your comment it turns out the Thermostat is the saftey feature... But what is that metallic thing then? I though thats one of those things that melts once it reaches a certain temperature, thus permanently cutting the circuit (think its called thermal fuse?), but it seems to me thats unlikely as companies usually cut costs if possible and two saftey features seems like "cuttable cost". But on the other hand I think those things only cost a few cents so might just be a double thing anways.

@MSusername69

Жыл бұрын

@@Gegi1992 I wouldnt call the thermostat a safety feature. its more like a feature to not let your water boil away if you happen to walk away for too long (intended use of the kettle aka make hot water). The thermal fuse is the actual safety thing so that IF your kettle boils dry (unintended effect) for some reason it wont just keep heating and set things on fire. Once the thermal fuse pops you have to replace or bypass it if you want to keep using the kettle because it permanently breaks the circuit.

what I like about this video is that it's the full scientific method there's a hypothesis, an experiment, an analysis, a new hypothesis based on the observed facts, until a conclusion is reached

Disassemble the handle of the white kettle you will probably find another bimetal disc integral to the main on/off switch. The discs may be stamped with 140/80. They open the circuit at 140° C and reset at 80° C. Also, clean the thermal paste off the thermal switch in the base and you'll see its set temperature. I discovered this when building a double boiler that used vegetable oil in the lower part to boil ethanol in the upper part.

I love this channel bc sometimes it's "look at this phenomenon no one has named and I'm exploring for what seems like the first time" and sometimes it's "I was very wrong about how kettles work"

I found out about how those kettles work many, many years ago, when the old Watchdog TV programme uncovered a few models of kettle, where design problems in that steam system was causing some nasty scaldings. It's a neat system, when it's made safely!

@EikottXD

2 жыл бұрын

Then help the dude out he literally asked in his comment how they worked..

@yomama3832

2 жыл бұрын

UNCENSORED S*X ASIANTEEN.SPACE 👆 Megan: "Hotter" Hopi: "Sweeter" Joonie: "Cooler" Yoongi: "Butter Asi con toy y sus mañas no se la lease que escriba bien mamon hay nomas pa ra reirse un rato y no estar triste y estresado.por la vida dura que se vive hoy . Köz karaş: ''Taŋ kaldım'' Erinder: ''Sezimdüü'' Jılmayuu: ''Tattuuraak'' Dene: ''Muzdak'' Jizn, kak krasivaya melodiya, tolko pesni pereputalis. Aç köz arstan Bul ukmuştuuday ısık kün bolçu, jana arstan abdan açka bolgon. Uyunan çıgıp, tigi jer-jerdi izdedi. Al kiçinekey koyondu gana taba algan. Al bir az oylonboy koyondu karmadı. ''Bul koyon menin kursagımdı toyguza albayt'' dep oylodu arstan. Arstan koyondu öltüröyün dep jatkanda, bir kiyik tigi tarapka çurkadı. Arstan aç köz bolup kaldı. Kiçine koyondu emes, çoŋ kiyikti jegen jakşı dep oylodu.#垃圾 Son unos de los mejores conciertos , no puede ir pero de tan solo verlos desde pantalla, se que estuvo sorprendente 💗❤️💌💘💟

@stevethea5250

2 жыл бұрын

@AGNÉZ Buny Girls i love how acknowledges his failed predictions

@buddyclem7328

2 жыл бұрын

@@stevethea5250 Why are you replying this to the spam pornography comment?

@jonathanodude6660

2 жыл бұрын

@@liam3284 that doesnt explain the results

I was inspired to autopsy my own $20 electric kettle; it came out of the new box with a broken heat trigger and will boil forever! It's been a few years of using it, so what the heck? I opened it up, damaged the gold connector ring, had to drill out three-winged-head screws, couldn't figure out why the trigger doesn't work, put it all back together and now it's super broken! Boiler repair: massive failure. Science: success! Taking your broken things apart and attempting to put it together again can help one learn more about physics, engineering, electricity, memory retention and so much more! I highly encourage this endangered practice. Not only do you become a more valuable asset for life in general, but you have a blast doing it. I'll go check out Mehdi again. Maybe there's some inspiration over there for me. I bet water boiler components could put a lot of power into other things entirely unrelated to drinking tea or coffee. Safety third. New water boiler second. More science first!

In my first college chemistry class we did this with mixed liquids. and separating and identifying them. If you raise the temp slow enough with control, you can catch the temp plateau for each chemical in the liquid and collect and recondense the liquids to see what ya got.

I always wondered why the handle of my kettle was getting partially hot, along the handle. I know understand why! Thanks.

@TheSecondVersion

2 жыл бұрын

Same. I wondered why my kettle wouldn't switch off even if steam was already clearly starting to rise from the spout, but it quickly turned off after the lid started to audibly "jiggle" from the pressure of the steam inside. That was probably the point where the pressure was definitely high enough to travel down the tube and heat the bi-metal

@samholdsworth420

2 жыл бұрын

I love these pr0n bots thank you KZread! dislike counter was definitely the glaring issue with your platform

@samholdsworth420

2 жыл бұрын

@@FieRcEOFF gay away bruh

@ChrispyNut

2 жыл бұрын

@@samholdsworth420 I'm sure Google/Alphabet intend to ensure that KZread loses money as there are so many annoyances, feature shortfalls, feature retractions and general crappiness, which really shouldn't be nearly as abundant for such a mammoth software company. I really miss the days when Google was a good* company, which support open source projects and strived to make the internet a greater platform overall.

@yomama3832

2 жыл бұрын

UNCENSORED S*X ASIANTEEN.SPACE 👆 Megan: "Hotter" Hopi: "Sweeter" Joonie: "Cooler" Yoongi: "Butter Asi con toy y sus mañas no se la lease que escriba bien mamon hay nomas pa ra reirse un rato y no estar triste y estresado.por la vida dura que se vive hoy . Köz karaş: ''Taŋ kaldım'' Erinder: ''Sezimdüü'' Jılmayuu: ''Tattuuraak'' Dene: ''Muzdak'' Jizn, kak krasivaya melodiya, tolko pesni pereputalis. Aç köz arstan Bul ukmuştuuday ısık kün bolçu, jana arstan abdan açka bolgon. Uyunan çıgıp, tigi jer-jerdi izdedi. Al kiçinekey koyondu gana taba algan. Al bir az oylonboy koyondu karmadı. ''Bul koyon menin kursagımdı toyguza albayt'' dep oylodu arstan. Arstan koyondu öltüröyün dep jatkanda, bir kiyik tigi tarapka çurkadı. Arstan aç köz bolup kaldı. Kiçine koyondu emes, çoŋ kiyikti jegen jakşı dep oylodu.#垃圾 Son unos de los mejores conciertos , no puede ir pero de tan solo verlos desde pantalla, se que estuvo sorprendente 💗❤️💌💘💟

The kettles need a vapor sensor to stop on boil, and they need an over-temp sense to protect the device if it were ever started dry with no liquid - in the latter case the vapor sensor would never detect an issue and the device could ignite. The over-temp could be a bi-metalic or it could be an electric resist sensor, or something else I suppose. But treat the with liquid and without as two separate cases and the sensors make more sense ;-)

@bonswouar

2 жыл бұрын

Thanks for the clarification, that's exactly what I was thinking from the start of the video: most cheap boilers seem to have a vapor sensor (= mechanic, very basic & cheap), the heat sensor is just for safety.... I was quite disappointed he didn't think about that, that seemed obvious

@yomama3832

2 жыл бұрын

UNCENSORED S*X ASIANTEEN.SPACE 👆 Megan: "Hotter" Hopi: "Sweeter" Joonie: "Cooler" Yoongi: "Butter Asi con toy y sus mañas no se la lease que escriba bien mamon hay nomas pa ra reirse un rato y no estar triste y estresado.por la vida dura que se vive hoy . Köz karaş: ''Taŋ kaldım'' Erinder: ''Sezimdüü'' Jılmayuu: ''Tattuuraak'' Dene: ''Muzdak'' Jizn, kak krasivaya melodiya, tolko pesni pereputalis. Aç köz arstan Bul ukmuştuuday ısık kün bolçu, jana arstan abdan açka bolgon. Uyunan çıgıp, tigi jer-jerdi izdedi. Al kiçinekey koyondu gana taba algan. Al bir az oylonboy koyondu karmadı. ''Bul koyon menin kursagımdı toyguza albayt'' dep oylodu arstan. Arstan koyondu öltüröyün dep jatkanda, bir kiyik tigi tarapka çurkadı. Arstan aç köz bolup kaldı. Kiçine koyondu emes, çoŋ kiyikti jegen jakşı dep oylodu.#垃圾 Son unos de los mejores conciertos , no puede ir pero de tan solo verlos desde pantalla, se que estuvo sorprendente 💗❤️💌💘💟

@robj4078

2 жыл бұрын

Ah good. That’s how I thought they worked.

Reminds me of how rice cookers work. It took a long time, but the invention of the rice cooker was one complicated mix of temperatures and weights to flip the switch to turn it off. Fascinating stuff as always Steve. Thanks for the videos! :)

if i remember the basics of heat transfer to liquids, it has to do with the form of vapor between the liquid and the heated surface. by increasing the temperature difference between these two the boiling goes through 4 different phases. 1- convection boiling 2- nucleate boiling 3- transition boiling 4- film boiling. vaporization reaches its maximum at nucleate boiling, after that if the temperature difference keeps rising then the efficiency decreases by creation of a thin layer of vapor between the liquid and the heated surface. I would guess the thermostat is also on the same heated surface, therefore at film boiling stage the kettle would go off

@youtubedrifter5594

Жыл бұрын

Convection

I never wasted a second thought about how kettles work, just assumed there would be a temperature sensor triggered at 100°C... this design is so clever! Thank you for teaching me this!

@emmanotsostrong

2 жыл бұрын

That’s actually how my kettle works because it also has settings for other temperatures too.

There's two different cutout mechanisms. One is the steam/condensation activated cutout for when the kettle is boiling. The other is to prevent the element overheating and causing a fire / meltdown when the kettle is switched on with no water in it, or in case the other cutout fails and it boils dry, or there's some other fault with the element that causes it to overheat.

@yomama3832

2 жыл бұрын

UNCENSORED S*X ASIANTEEN.SPACE 👆 Megan: "Hotter" Hopi: "Sweeter" Joonie: "Cooler" Yoongi: "Butter Asi con toy y sus mañas no se la lease que escriba bien mamon hay nomas pa ra reirse un rato y no estar triste y estresado.por la vida dura que se vive hoy . Köz karaş: ''Taŋ kaldım'' Erinder: ''Sezimdüü'' Jılmayuu: ''Tattuuraak'' Dene: ''Muzdak'' Jizn, kak krasivaya melodiya, tolko pesni pereputalis. Aç köz arstan Bul ukmuştuuday ısık kün bolçu, jana arstan abdan açka bolgon. Uyunan çıgıp, tigi jer-jerdi izdedi. Al kiçinekey koyondu gana taba algan. Al bir az oylonboy koyondu karmadı. ''Bul koyon menin kursagımdı toyguza albayt'' dep oylodu arstan. Arstan koyondu öltüröyün dep jatkanda, bir kiyik tigi tarapka çurkadı. Arstan aç köz bolup kaldı. Kiçine koyondu emes, çoŋ kiyikti jegen jakşı dep oylodu.#垃圾 Son unos de los mejores conciertos , no puede ir pero de tan solo verlos desde pantalla, se que estuvo sorprendente 💗❤️💌💘💟

@dutubsucks

2 жыл бұрын

This was my thought as well, they need a safety for when the kettle is turned on when dry...

@calmeilles

2 жыл бұрын

There should be three: the third also acts through bi-metallic distortion at a yet higher temperature and with more decided force, popping the kettle off its electrical contacts in the base. It re-sets automatically when cooled and the kettle pressed down on the base. In old-style kettles with the plug on the side this was a prong that would spring out and had to be re-set manually, usually by forcing the plug back in against the considerable resistance of the spring until it once more latched against the bi-metallic catch. This was actually the first safety feature in early electric kettles that relied on the human remembering to switch them off when boiled. 😀

Another consideration is that while liquid will not go above its boiling temperature at a given atmospheric level, when it flashes to steam/vapor it can then get much hotter. It could be the temperature of the steam which is able to allow the vessel to reach that temp level.

Someone probably already answered, but in case not - there is 3 types of sensors in kettles: pressure (main), temperature (boil dry protection, in most countries required by low) and liquid (used in some expensive or professional kettles - few countries requires by low). Main (pressure) sensor usually is just on off button mechanism pushed back by steam - no actual electronic. Pure alcohol boiled and created enough pressure quicker. If you just hold the button it will continue boiling. Temperature sensor usually cut off power if base gets to around 110-120 C. In most cases it should not let power go until on off button used. Some old kettles keep turning on and off. Liquid sensor just duplicates electrical fuse (mostly used with detachable bases or where law requires)

I love it when experiments go "wrong" because you learn something.

@NeonRahkshi

2 жыл бұрын

the good kind of wrong, yes

@kissingfrogs

Жыл бұрын

And awesome that experiments still get done when confident of the outcome, to then be proven wrong

The episode is such a great example of what makes this channel uniquely science-minded. Steve grasps the basic principles involved and explains them well, and in the rare instance where there's something left unexplained, the spirit of discovery is still there! What a crazy weird and funny outcome! This channel is where real scientists and engineers can provoke real thinking and develop clarity and knowledge!

The component you pointed to on the white kettle isn't the shut-off for when it boils. That is a device called a thermal switch. The idea in this instance is it will cut power to the element if the base of the kettle gets too hot (e.g the kettle boils dry or someone turns it on with no water in it). It's a protection device so the kettle doesn't go nuclear and burn the house down. These thermal switches are self-resetting, so can't be used as a shut-off for when the kettle boils. Otherwise, after a while they would reset and start it boiling again. The shut-off for boiling must be elsewhere, probably in the handle.

I learned about the steam based sensor a while ago by accidentally boiling a kettle dry because fhe lid didn't catch and popped open while unattended. Luckily there's definitely a secondary overheating safety that shuts everything off in case the kettle boils dry or if someone turns it on with no water inside... What was also interesting was that it must have been something internal and early in the circuit, because after tripping that protection the kettle refused to start again even with the bimetallic switch depressed and latched and cold water inside. It even reset itself after a while which all the more surprising given I thought I tripped some one-time thermal fuse... so much safety design in a $10 kettle...

@shakkabo

2 жыл бұрын

@Lankia Yuta what

@szczur0192

2 жыл бұрын

@Lankia Yuta lmao

@User-md3ul

2 жыл бұрын

well there's your fire hazard protection

@Ktulu789

2 жыл бұрын

There's a thermal fuse that goes off above certain temperature. It will reset itself after a while, when it cools down. Meanwhile you can't power it on anymore. Probably the fuse that Steve found was the thermal fuse and not the triggering mechanism.

I live over 4000 feet (1.2 km) above sea level. I used to have a “dumb” kettle that would shut off properly. I always assumed it shut off when the temperature stopped going up, presumably because the water was boiling, but perhaps it has a hidden tube like your second kettle. When my old kettle broke, I replaced it with a “smart” kettle with lots of below-boiling options (180 F, 190 F, 205 F, and “Boil”). Something about various kinds of tea needing different temperatures for optimal steeping. If I set my new kettle to boiling, it’ll boil and boil and boil, not shutting off. I’ve admittedly never let it boil dry, so maybe it’d stop eventually. I have to use the 205 F setting (96 C) to get it to shut off, though at my altitude the water still boils on that setting for about ten seconds before the kettle shuts off.

@vulpo

2 жыл бұрын

I have the same kettle and the same problem exactly. They should really have a back-up sensor-switch like the kettles in this video to shut it off when it starts boiling regardless of the temperature.

@andrius0592

2 жыл бұрын

At sea level, kettles do tend to boil the water for about 10 seconds before switching off. Even those that have digital dispay of temperature.

@MrNicoJac

2 жыл бұрын

@@andrius0592 Theoretically, yeah... But if a volcano blows up on the other side of the globe, and a few hours later the air pressure in your area goes up, then your water suddenly needs to be 101 C to start boiling

@gizmoguyar

2 жыл бұрын

I suspect that the old kettles used this design because accurate temperature measurement actually used to be expensive. But nowadays microcontrollers, and accurate temperature sensors are so cheap, that they use that to detect boiling instead. The reason that it keeps boiling for 10 seconds probably has two reasons. Even modern temp sensors are not perfect (maybe 1-2 degrees accuracy). So the microcontroller likely needs about 1-2 degrees of margin to make sure the water is capable of reaching a *higher temp than the shutoff point. If the sensor only shuts off when it reads exactly 100, it might not always shut off if the water happens to boil at 99.2. That is, they design it to shut off when the sensor reads 98 degrees. But if it shut off immediately without actually boiling, users would be annoyed, so they design it so that the sensor temp is delayed slightly. When the temp sensor reads 75 degrees, the water is probably at 77 degrees. That way, once the sensor reads 98, the water is actually already boiling (or has been for a few seconds). If the sensor is not quite accurate, the water will continue to boil, and the sensor will *eventually switch off. In your case, though. The true boiling temperature is clearly below the temperature margin programmed into the microcontroller. For the lower temp modes, the microcontroller heats the water more slowly as it approaches the target temp. This gives time for the sensor to catch up to the temp of the water. In your case, this might also explain why it continues for 10 seconds.

@umi3017

2 жыл бұрын

I live at 2000m(6000+ft) and my kettle just works fine.

Never thought about why a double boiler works in the kitchen, it's just one of those culinary techniques that every one just touts. Definitely a light bulbs moment seeing that, never put the physics of phase transitions together with the cooking application like that. Left more confused by kettles than ever before though... 😅

It's astounding! I finally understood how my kittle (?) works. Thanks Steve

Fun fact, the effect shown in the first demonstration is called fractionation. When you have a mix of fluids with different boiling points, the combined fluid has a new boiling point in the middle, but when boiled they evaporate at different rates. It's an incredibly important thing to know about if you work in the field of HVAC/R.

@lars3509

2 жыл бұрын

It doesn't have to be in the middle, though. Most real binary mixtures have an azeotropic point, which is either the highest or the lowest boiling point of any two ratios those two ingredients can be mixed, including the pure substances. For water/ethanol, the azeotropic point is a low-boiling azeotrope with a boiling point of 78,2 °C, where pure ethanol boils at 78,4 °C. The azeotrope is also the point, where the vapor concentration of both liquids in equilibrium are equal and therefore no separation with pure destillation ist possible.

@TheMinecraftACMan

2 жыл бұрын

@@lars3509 I realize I didn't phrase that the best. What I mean is that the boiling point of the mixture would be between the boiling points of the two ingredients.

@deus_ex_machina_

2 жыл бұрын

This video by Tech Ingredients is a good overview of fractional distillation: kzread.info/dash/bejne/oXZ8q8VvfNquZtI.html

@HappyBeezerStudios

2 жыл бұрын

Important for distillation, setting it to around 80-85°C should be enough for the ethanol to vapour away, but the water to stay.

@fungdark8270

2 жыл бұрын

@@HappyBeezerStudios you’d be there forever. The true way to get higher concentration in one run is a reflux column or fractionating column I think they are called. They work by exposing condensedate to hot vapor and essentially redistilling as you go. Imagine the 80/20 mixture condensing from the vodka being reheated by the 80/20 vapor and resulting in 90/10 vapor mixing with the original 80/20 vapor. This is basically how refining of petroleum products work as well. When you drive by a refinery, all those tall tubes with pipes coming out of the top are fractionating columns. Pretty cool

Nice video! If you wipe the thermal paste from the switch, you will discover that is set above 100 degrees C, it is used as a safety switch in case the bimetalic switch fails or the Kattle boils dry. In general, the temperature of the safety switch is 130 degrees C.

Thanks Steven, loving the curiosity stream documentaries.

Another approach that would work (though clearly not used by either of the kettles in this video) would be a temperature sensor leading to a small microcontroller. If the temperature is rising, then stay on. If it stops rising then that means the liquid is boiling, so turn off. And if the temperature gets past a failsafe point well above water's bp, shut off.

There are actually some rice cookers that behave similar to how you thought the kettles would behave, because they actually use a difference in magnetic conductivity due to heat to trigger the off switch. Although those are tuned to build dry and turn off after reaching about 102-105C, but I'm curious if there are any kettles that use a similar mechanism.

@complainer406

2 жыл бұрын

There's kettles with options to shut off at lower temperatures (e.g. for green tea). Might be more likely to find it in a kettle like that since you wouldn't be able to rely on vapors.

@vulpo

2 жыл бұрын

See this Technology Connections video for a good explanation: kzread.info/dash/bejne/hIeIsMqvdKrIiaw.html

@meneldal

2 жыл бұрын

The difference is for a rice cooker you want all the water to be gone, unlike a kettle. When all the water is gone, temperature increases quickly and that's easy to detect. Japan has a lot of kettles that keep water at a given temperature (not boiling, typically 80-95C), with settings allowing you to choose the temperature. So they are actually measuring the temperature properly there.

@xToddmcx

2 жыл бұрын

@@complainer406 I have one of those kettles, I think it's just computer controlled. Reads the temperature with a thermometer and turns off when it hits a set level. There's certainly no steam tube in it and it works with the lid off. I don't know how it knows what the boiling temp is at higher altitudes is, although I do know it works at them. Maybe it's just programmed to assume the liquid is boiling once the temperature stays steady for a bit. The old rice cookers he's talking about work by detecting when the temperature at the bottom of the kettle goes above the boiling temperature of water. Because that means all the water has boiled off, so the rice is done.

@yomama3832

2 жыл бұрын

UNCENSORED S*X ASIANTEEN.SPACE 👆 Megan: "Hotter" Hopi: "Sweeter" Joonie: "Cooler" Yoongi: "Butter Asi con toy y sus mañas no se la lease que escriba bien mamon hay nomas pa ra reirse un rato y no estar triste y estresado.por la vida dura que se vive hoy . Köz karaş: ''Taŋ kaldım'' Erinder: ''Sezimdüü'' Jılmayuu: ''Tattuuraak'' Dene: ''Muzdak'' Jizn, kak krasivaya melodiya, tolko pesni pereputalis. Aç köz arstan Bul ukmuştuuday ısık kün bolçu, jana arstan abdan açka bolgon. Uyunan çıgıp, tigi jer-jerdi izdedi. Al kiçinekey koyondu gana taba algan. Al bir az oylonboy koyondu karmadı. ''Bul koyon menin kursagımdı toyguza albayt'' dep oylodu arstan. Arstan koyondu öltüröyün dep jatkanda, bir kiyik tigi tarapka çurkadı. Arstan aç köz bolup kaldı. Kiçine koyondu emes, çoŋ kiyikti jegen jakşı dep oylodu.#垃圾 Son unos de los mejores conciertos , no puede ir pero de tan solo verlos desde pantalla, se que estuvo sorprendente 💗❤️💌💘💟

I really like how you present a wrong hypothesis that makes sense and show yourself working through the problem and proving it.

Steve - Many kettles have a port in the handle near the top of the kettle that also serves to turn off the unit when vapor reaches it. It would be interesting to see if your kettle has that control.

Wow... what a learning... This video is the correct way how one should learn science and any other thing of this world, Develop a hypothesis, test it out, learn from the test and repeat the process... Also accepting that one can be wrong is a great trait to possess

"I bet making the kettle turn off automatically will be difficult" "No, it will be super easy, barely an inconvenience". Loved the homage to Pitch meetings at the end

@Doncergio

2 жыл бұрын

10:34 also has the sound effect while showing some clickbait article.

@scottwilliams895

2 жыл бұрын

Kettles boiling alcohol is tight!

4:53 fun fact: bimetalic strips is how christmas lights used to flash before eletronic controls were used. a bimetallic strip connected the main wire with the filament. this strip got hot (joule effect) when the light was on, so it would curve and disconnect, turning off the light. but then it would cool down, go back to the initial position and connect, and turn the light on. and get hot and so on... i think car blinkers worked the same way

@kacperfilipek8461

2 жыл бұрын

Yeah, old school blinkers used to work this way. Technology Connections made a neat video about it.

Love this series of videos, great job!

this depends on the kettle probably. id love to see this same experiment with my personal kettle, one that you set the temperature to with a visible thermocouple in the base of it. if i set it to 100C and pour isopropyl alcohol i feel like it’ll just boil over until dry, and the air temp from convection alone makes it turn off

@youtubedrifter5594

Жыл бұрын

There you go!! Convection! Smart fella. Convection is the key.

The sensor at the bottom of the second kettle is a safety cutout to prevent damage if it boils dry. There will be a bi-metallic switch in the handle which the vapour trips.

@brettb2516

2 жыл бұрын

100% correct.

@RupertReynolds1962

2 жыл бұрын

That's the usual way I've seen. The sensor (bimetallic strip or whatever) is set a bit below 100°C, but the delay in steam reaching it and heating it means the kettle has been boiling for a few seconds when it trips. I'm told some electronic kettles (some of the ones that can be set to stay hot, I guess) use more exact sensing of water temp instead, but I've never seen one doing that. All the ones I've seen let the steam heat something in the handle. And they run forever if you don't close the lid, because not enough steam goes through the handle :-)

@complainer406

2 жыл бұрын

@@RupertReynolds1962 My kettle has options to turn off at lower temps, so it must be detecting the temp, it must also have one of those vapor detectors though since it always shuts off when the water's boiling (I live at a high elevation so water only boils at 95C and it shuts off fine)

@RupertReynolds1962

2 жыл бұрын

@@complainer406 There's a thought. I hadn't thought that altitude would make that much difference, unless you live halfway up Mt Everest!

@seraphina985

2 жыл бұрын

@@RupertReynolds1962 I would not be surprised if those still include the standard two bimetal strips for boiling and thermal overload detection that likely physically throw the power switch still. Ultimately they have fewer failure modes than the thermistor, microcontroller and mosfet setup so they make for better safety devices.

I had thought it would turn off when the temperature stops rising; once the temperature stops rising, it has to be boiling. Therefore, a liquid that boils at a lower temperature would switch off the kettle earlier. Rice cookers, I think, work by detecting when the temperature rises above the boiling point of water, which entails that there is no water left.

@philw9339

2 жыл бұрын

this is the answer

@CooChewGames

2 жыл бұрын

@@philw9339 Really?? That has made my day... :-D

An odd thought. But I really appreciate the speed that you are talking at. It's not over-hyped, all over, like many youtubers now days. Also admiting that your prediction was wrong, instead of just re-shooting it, good science.

I wish you have been my thermodynamics teacher back in college. You explain everything so clearly.

4:00 that's also one of the features of a pressure cooker. You can achieve temps higher than 100C under pressure. Faster cooking and forces the heat into the food.

@ikitclaw7146

2 жыл бұрын

I hate being near my pressure cooker when its on lol my kettle lid flipped open and launched water out, cnt imagen what that would do if it failed.

Here is an interesting concept to consider when talking about boiling (not the solution to this video, other comments explain that well enough). Boiling is not one set mechanism that works the same every time like you seemed to think in this video. In fact, there are many stages of boiling depending on the difference between the surface temperature and boiling temperature (Temp of saturation) of the liquid. If the difference is small then natural convection boiling occurs which the kettle is typically going to achieve. However, if the difference is even 5 degrees C, nucleate boiling occurs. If the difference is more than 30, a very special thing happens! Up until that point the liquid continues to have a higher heat flux from the surface, yet at this point a film of vapor gets in between the surface and the liquid and heat flux steadily decreases until the minimum heat flux occurs at the Leidenfrost point (which is a fun phenomenon to see with water droplets on a searing hot pan). After that point film boiling occurs where radiation heating becomes significant enough to increase the heat flux yet again and that is the final stage. Hope soommeeonee enjoyed this very small lecture that no one asked for :)

@FirstLast-cc6cv

2 жыл бұрын

It was a worthy read, and I learned something new

@kuykendallwebfamily

2 жыл бұрын

@@FirstLast-cc6cv sick :)

@szr8

2 жыл бұрын

Thank you for this :)

@RC-nq7mg

2 жыл бұрын

Pressure also makes a huge difference. On top of that you can superheat water in a microwave oven only to have it flash boil when disturbed.

@kuykendallwebfamily

2 жыл бұрын

@@RC-nq7mg yes the boiling temp would be accounting for whatever atmosphere the liquid is currently in. And wow I didn't realize that was possible! Going to try and do it myself now haha

It was an amazing video, my attention was glued to the screen!

The greatest battle on KZread - Steve vs a Kettle

When the fluid is boiling, bubbles form on the heating element, these parts of the heating element are no longer being cooled by fluid contact and can therefore heat up rapidly. The kettle is turning off because the heating element is getting too hot, (which is indeed the kettles 'boil dry' protection), the lower boiling point of the ethanol mix causes large bubbles to form at the lower temperature thus triggering the shutoff.

@xmarine73

2 жыл бұрын

Liquid is a far better conductor of heat than air. If we assume the bubbles are 5° hotter than the surrounding liquid, surely the liquid would absorb that heat rather quickly. Also the bubbles don't stay on the heating element for long at all (not even a second) before being displaced again by liquid. Additionally there are far less bubbles along the element than volume of liquid. So even if the liquid were cooler than the air the and the air was super heated, I doubt there would be much of a temp change registered by the element due to the bubbles alone.

@shaniamonde7341

2 жыл бұрын

@@xmarine73 Liquids, water inparticular, have a very high thermal capacity, this is not the same as being a good conductor. Infact water has pretty decent insulative qualities, it is very slow to change its temperature relative to its surroundings (why you get liquid water in lakes in midwinter, and why oceanic warm water currents can transport heat so far). Each individual bubble doesnt stay in contact with the surface for very long no, but as soon as it seperates it is immediately replaced by another one. Air bubbles (or any other voids) in a heat exchanger can cause localised hotspots which can very rapidly damage the structure.

@xmarine73

2 жыл бұрын

@@shaniamonde7341 we don't put boiled eggs in cold air (freezer or refrigerator) to stop them from being overcooked... we put them in cold water. Why is that? The sheer volume of liquid, in this experiment, versus the relatively small amount of air would indicate that the allegedly super heated gas that is cooled very quickly by the cooler liquid surrounding it. Another way to prove this is pretty simple (and I'm sure we've all done this). Boil a pot of water. Once it's boiling place your hand over the pot relatively close to the water (being careful to prevent being splashed) and test the heat. The gases coming off the pot are much cooler than that boiling liquid that you would never put your hand in. Sure there's a bit of diffusion with "room temperature" gases at the surface of the liquid but we're talking superheated gas, right? Which is hotter right at the surface - the gas or the liquid? If you were to put a mug into the water and capture the gas and the same mug into the water to scoop a water sample... which has the hotter contents? Are you claiming the gas bubble that's created and potentially super heated gives up that heat in the extremely short distance/time it travels through the water before being expelled?

@Peichen01

2 жыл бұрын

Thanks. That theory makes and we’ll see if he’ll do a follow up and find the reason

@shaniamonde7341

2 жыл бұрын

@@xmarine73 Eggs cooled in water as waters high thermal capacity allows it to absorb a lot of energy without changing temperature. Also easy access to an essentially infinite free flowing cold fluid, air cooling would give no forced convection unlike a running tap. Do not put your hand over a pot of boiling water! The water vapour coming off the boiling water is by its very nature more energetic than the liquid water... that is why it is steam! As stated in the video liquids cannot exceed their boiling point (unless held under special conditions, pressurised etc) the only way the additional energy can be absorbed is by the liquid transforming into steam. Steam has no such upper temperature limit and can be many times hotter than the liquid. The reason steam may 'feel' colder is that you have less contact between your hand and the steam, it is diluted into a large volume of ambient air. And yes steam does give up its heat very rapidly, that is why any surfaces near boiling water get covered in condensated water, immediately on contact with a colder surface the steam deposits its energy and reverts to a lower temperature (energy) state, ie water.

Love that he showed the whole scientific method to reach the conclusion and not just 'kettles 101'

@yomama3832

2 жыл бұрын

UNCENSORED S*X ASIANTEEN.SPACE 👆 Megan: "Hotter" Hopi: "Sweeter" Joonie: "Cooler" Yoongi: "Butter Asi con toy y sus mañas no se la lease que escriba bien mamon hay nomas pa ra reirse un rato y no estar triste y estresado.por la vida dura que se vive hoy . Köz karaş: ''Taŋ kaldım'' Erinder: ''Sezimdüü'' Jılmayuu: ''Tattuuraak'' Dene: ''Muzdak'' Jizn, kak krasivaya melodiya, tolko pesni pereputalis. Aç köz arstan Bul ukmuştuuday ısık kün bolçu, jana arstan abdan açka bolgon. Uyunan çıgıp, tigi jer-jerdi izdedi. Al kiçinekey koyondu gana taba algan. Al bir az oylonboy koyondu karmadı. ''Bul koyon menin kursagımdı toyguza albayt'' dep oylodu arstan. Arstan koyondu öltüröyün dep jatkanda, bir kiyik tigi tarapka çurkadı. Arstan aç köz bolup kaldı. Kiçine koyondu emes, çoŋ kiyikti jegen jakşı dep oylodu.#垃圾 Son unos de los mejores conciertos , no puede ir pero de tan solo verlos desde pantalla, se que estuvo sorprendente 💗❤️💌💘💟

In the small white kettle the little round thing is only for overheat protection (when there's no water in the kettle) the actual thermal trip is somewhere else.

I can explain what's going on here. Every time you boil a mixture you get a mixture. You will never boil a mixture dry. It will give you an 80/20 and then 70/30 and then 60/40 etc. You did a great job of explaining it too. This is one of those paradoxes that keeps you on your toes! It takes the same energy to raise a kilo of water 1° centigrade than to heat the entire pot to 100°C. I know it's crazy but it's basic physics. PV=8.413×n×T where n is moles of water (18.314mL is a mole) and T is in Kelvin or 273.15+C

I do notice the "lid thing" with my kettle, if the lid isn't fully closed the kettle will boil for about 30 seconds before switching off. I suppose they're designed to work at a certain pressure, accounting for steam coming out of the spout, and through the filter, etc.. Like, they build the kettle and then design the bimetal strip mechanism, maybe through trial and error, to switch off just when it boils, not too long, not too quickly..

@BramLastname

2 жыл бұрын

I believe that's actually a safety function, If there's too much pressure build up Opening the lid could cause nasty burns.

@mysticmusical

2 жыл бұрын

Welp! I couldn't find the humidifier years ago when I had a cold and just used my first kettle with the lid open. Fell asleep and it boiled dry... I'm flipping lucky I didn't die or anything aren't I 🤧

@liamholcroft7212

2 жыл бұрын

@@BramLastname doubt it, i don't think a kettle is capable of holding enough pressure, or generating steam fast enough for the pressure to increase momentarily. However if the kettle was able to do such a thing, I would agree. EDIT: on second thoughts perhaps it was designed that way anyway regardless of the pressure function being needed.

@JoeBob79569

2 жыл бұрын

@@mysticmusical Damn, I wish I lived somewhere dry enough that I needed to use a humidifier. Here in Ireland the struggle is trying to dehumidify your house..

@BramLastname

2 жыл бұрын

@@liamholcroft7212 in theory it's possible if the little steam pipe gets blocked by something But I agree it's likely not an intentional design.

I did work experience at a leading Kettle Control manufacturer in the testing department (at age 16 mind you, so some bits are a little bit foggy and I don't claim to be an expert but anyways), and learned a bit about how these things work. I didn't see how the control on the white one works, but I'd imagine it's very similar to the first one, just with different mechanics. The steam tube (in this case through the handle) pumps steam down to the base of the kettle, where it cuts the power. This triggers below 100c because as you said, steam can be below 100c, and also it speeds up the trigger time, as the bimetallic strip also takes some time to heat up. There is then a second (or second and third in the case of this manufacturer, in case one fails) which triggers above 100c, which covers the boiling dry function (much like a rice cooker) and the testing rig for this was very interesting. If you were to take the control (the big black thing with the electrical connector) off the first kettle, you would likely find 2 more bimetallic strips on the top of it, which are either in contact with or at least very close to the heating element. The white kettle seems to have a similar working principle, just the control is condensed into one unit, with either 2 strips or a digital IC in it.

@Mueller3D

2 жыл бұрын

I don't think steam will normally be below 100c (for the same reason that water is not normally above 100c). However, steam mixed with air can be below 100c.

@kilian8250

2 жыл бұрын

Carl Mueller steam from other elements, for example ethanol. Did you watch the video?

@moczikgabor

2 жыл бұрын

@@chyza2012 I consider this pure nitpicking, since the OP was right: 1. pure water's steam can be colder than 100 degC (at lower pressure), 2. the liquid (pedantic, heh? 😜) can be non-pure water with different boiling point, and 3., the most important: in science, in real world, there is no such thing as IS or Equal. There is only "similar", "close to", "within certain tolerance". And this is not nitpicking: once anyone start engineering something, in any profession, will encounter that practically there is no such thing as "equal".

I have some probable solution in the unlikely case it is not solved by now. Gas is usually not a good heat conductor, while liquid is, and the switches, don't really shut down by the liquid temperature but the heating plate temperature. Now if the liquid is not boiling it has full contact and cools the heating plate down, now if it gets hot enough to boil the liquid, the liquid itself is still well below boiling temperature but the liquid directly touching the plate reaches this boiling temperature and changes its state. And now this now gas isolates the plate a bit, and if the boiling increases the plate gets more and more isolated and goes quite a lot over that boiling temperature and throws the switch. And because of that the kettle turns of regardless of the boiling point of the liquid (high boiling point liquids will take longer though). And this will also throw the switch faster if the boiling point is lower.

3:30 not only did your prediction match what I was thinking exactly, you answered The other question I was thinking right after! Must be reading my mind through the screen haha Very intriguing as I initially believed that you could because well, you can heat water up after the ice has melted and air seems to feel warm and cold so surely wants something reached its boiling point it can be heated further Your explanation makes sense though, thanks

I'm a chemical engineer and was very pleasantly surprised by the accurate explanation of boiling kinetics and concentration difference in water and vapor phase. Very well researched!

@isaacmalik3714

Жыл бұрын

your pfp brought back memories lol

3:50 , You can in fact superheat a liquid. Water can be heated above 100c without much active boiling going on. If you take distilled water and try boiling it in extremely polished pot or kettle or beaker you'll see it yourself, but beware that reaction of superheated liquid to any contaminants is pretty... violent.

@I.C.Weiner

2 жыл бұрын

Pressure cookers also work.

@urhop1999

2 жыл бұрын

@@I.C.Weiner thats not superheated liquid tough since pressure changes the boiling point

@slowfudgeballs9517

2 жыл бұрын

@@urhop1999 If you can supercool something you might be able to superheat it. Supercooled water IS a thing, you are preventing the molecules from forming a solid crystal structure by not letting the water grab onto anything to even start the solidification process (contaminants or any amount of ice formations/disturbances). Same thing can probably done with a gas.

@urhop1999

2 жыл бұрын

@@slowfudgeballs9517 I know

@slowfudgeballs9517

2 жыл бұрын

@@urhop1999 Yeah but it's really cool isn't it? Now more people know.

In every kettle I disassembled there was a bimetal switch in the base of the kettle, this switch type switches a kettle off when a bimetal spring inside it bends at certain temperature. BTW, over time a contact on that spring becomes contaminated with soot from electrical arc burning it (and probably dust), so it's a matter of disassembling the switch and cleaning the contact point... So idk who in the world still uses steam to detect boiling when the whole point of boiling the water is bringing it up to a certain temperature, not evaporating it. Plus, if you turn an empty kettle on, there's no steam, but the bottom gets hot anyway, very fast, so the swich acts as a safety device, shutting the empty ketttle off. This, I guess, is not an option for kettles with an internal heating spiral, as their bottom does not heats up itself, but all the metal flat bottom ones I saw had this switch.

This was way more interesting than I thought, kudos!

Never would I have expected to ever watch a full 12minute video about flipping kettles ... but here I am ... and I enjoyed every second of it lmao! New subscriber :D this was so interesting!

I think the reason you didn't figure this out is because you forgot one function of a kettle. You assume that it's function is to boil water but that's only half of it, any piece of wire can do that. Kettles have 2 functions: 1: Boil water (more accurately bring it up to a boil) 2: Don't burn the house down.

@krashd

2 жыл бұрын

Which is why the kettle, and all kettles, have two switches with the second switch taking care of the second point you mentioned.

@MrRolnicek

2 жыл бұрын

@@krashd Well both switches would be taking care of the second function. That was sort of my point, generating heat is literally the easiest thing to do in an appliance. If you make any sort of appliance and fail so miserably as to make it 0% efficient, you've still made a heating device which is 100% efficient in its heating, while reaching 100% efficiency in any other application is practically impossible.

The key difference between the two kettles is the location of the switch. The black kettle has the switch at the bottom part (0:16) whereas the white kettle has the switch at the top (7:35). This is why the black kettle needs that metal tube to conduct the vapor downwards where the switch is. The white kettle, on the other hand, only needs a hole at the top because the switch is right there.

dude I swear all your videos are so cool

Getting an infrared thermometer may help test the hypothesis of the thermal switch in the white kettle as well as allowing you to see the temperature that the switch turn off at (if it indeed does turn off at a specific temperature).

@wolu9456

2 жыл бұрын

a part number for finding the datasheet to find out what that thing is would be my first action. screw him if he left that out.

@yomama3832

2 жыл бұрын

UNCENSORED S*X ASIANTEEN.SPACE 👆 Megan: "Hotter" Hopi: "Sweeter" Joonie: "Cooler" Yoongi: "Butter Asi con toy y sus mañas no se la lease que escriba bien mamon hay nomas pa ra reirse un rato y no estar triste y estresado.por la vida dura que se vive hoy . Köz karaş: ''Taŋ kaldım'' Erinder: ''Sezimdüü'' Jılmayuu: ''Tattuuraak'' Dene: ''Muzdak'' Jizn, kak krasivaya melodiya, tolko pesni pereputalis. Aç köz arstan Bul ukmuştuuday ısık kün bolçu, jana arstan abdan açka bolgon. Uyunan çıgıp, tigi jer-jerdi izdedi. Al kiçinekey koyondu gana taba algan. Al bir az oylonboy koyondu karmadı. ''Bul koyon menin kursagımdı toyguza albayt'' dep oylodu arstan. Arstan koyondu öltüröyün dep jatkanda, bir kiyik tigi tarapka çurkadı. Arstan aç köz bolup kaldı. Kiçine koyondu emes, çoŋ kiyikti jegen jakşı dep oylodu.#垃圾 Son unos de los mejores conciertos , no puede ir pero de tan solo verlos desde pantalla, se que estuvo sorprendente 💗❤️💌💘💟

White kettle still has thermobimetallic switch on the main switch, it's just located on the top and there is a channel you mentioned. Those switches are single assembly with small coin shaped bimetallic part that just clicks them off. The thing on the bottom is probably a current limiter or safety switch to prevent burning the device which would shut off at much higher temperature.

This is a really nice demonstration of the effect

Wow, I just checked the design of my electric kettle (in Europe) and it also has a cleverly masked hole in the lid hinge. Definitely this hole located below the hinge leads steam into handle and down to the switch. And I don't know when they started to do such things. I clearly remember much simpler kettles in the past, maybe ten years ago...

@Imaboss8ball

Жыл бұрын

I don't think you can get much simpler than that for an electric kettle that turns off automatically.

My best guess is that they operate by measuring temperature over time. Once the temperature goes from increasing to staying within let’s say 1° C for 30 seconds, it would assume that the liquid is now boiling. That would explain why in the first kettle, it boiled for a long time because as the liquid became a higher concentration of water, it’s temperature continued to rise, until the increase in temperature in that arbitrary “30 seconds” was low enough to trigger the system to shut off. In the second one, as the sensor is attached to the base, it may also just be waiting until the temperature stops changing to trigger the system to shut off. Thanks for the great video!

@R2D2SD

2 жыл бұрын

I believe that would require electronics but there's none of that inside

The mechanism I had always assumed was that it was detecting when the temperature *stopped* increasing, since when water (or whatever liquid) reaches the boiling point, extra heat goes into boiling it rather than increasing the temperature.

@rock4cheese

2 жыл бұрын

That actually sounds like a better design. I don't know whether it would be cheaper to manufacture though

@ac17dollars

2 жыл бұрын

@@rock4cheeseput in an empty kettle then it would just melt into oblivion

@victortitov1740

2 жыл бұрын

i think that is how microcontroller-operated kettles do it; i'm not sure though. I have one. It turns off even with the lid open (although sometimes it takes a while), yet has problems turning off with only a small amount of water in it (not sure why).

Wow! Of all the things I never needed to know about this is the most interesting one.

10:08 yep! That’s what it’s for. It’s a boil dry detector. It’s there for if the unit is turned on and there is no water in it (no vapor to turn it off) once the unit reaches a certain temp, it shuts off. That’s why the thermal paste is there - to ensure that function works properly.

This is such a great video because you start with something so simple as boiling water and you keep diving deeper and deeper into figuring out the whole scientific and engineering principles with each experiment.

7:09 there is a hole that goes into the handle. Also the thermal switch is for if the kettle boils dry, as this type of kettle is found in a lot of student accommodations it will cut all power as not to cause an electrical fire.

@redbeard3946

2 жыл бұрын

This is the future of humanity: people that don't have the attention span to watch a whole video over 10 mins.

I don’t know why I am here but this is why I love KZread and this dude is incredibly likeable.

I live in the mountains where water boils at 202F (94C). You have to cook things (like boiled eggs) longer because the temperature is lower. Or use a pressure cooker.

It's funny, at the beginning of this video I was surprised when you said electric kettles worked by measuring temperature. I had always assumed it based of the steam created by the boiling water. Don't know where I got the idea but feels nice to know I was somehow right :)

@adog3129

Жыл бұрын

I didn't even know that they shut off automatically. Never used one. This video was an introduction to electric kettles for me.

@Tennouseijin

Жыл бұрын

I was also wondering "but would they really make it based on a temperature sensor? Would that be reliable?" After all, you do want the kettle to turn off even at higher altitudes/low pressure, but you don't want it to turn off too early at sea level, so there's no 'one size fits all' temperature-based solution. Not to mention, it would need a fairly precise sensor. A few degrees off, and you either end up turning off before the water starts to boil, or you end up waiting for the water to reach, say, 102 C, which it never will. If anything, I would expect perhaps something based on the rate of temperature change, as that could give you some insight into what is happening in the kettle (the temperature rises too quickly? Uh oh, perhaps the kettle is empty! The temperature rises slowly? Good, we're heating up the water. The temperature stops to rise? Looks like it's boiling. Though there's also the issue that once the water starts boiling, you get vapor bubbles at the base of the container, which means there's less liquid water touching the heating plate, which could also allow the plate itself to maybe continue heating up, dunno.) Still, while in theory maybe such a solution could work, it would probably be way more complex than what they actually use.

@lollycopter

Жыл бұрын

> Don't know where I got the idea but feels nice to know I was somehow right :) I got the idea from the fact that the water is clearly boiling for quite a bunch of seconds, yet still takes a while for the kettle to switch off. I wonder what happens with a kettle with no water? I notice the cheap kettles mention they have some kind of boil dry protection built in or something, but I've never dared to test it.

@Tennouseijin

Жыл бұрын

@@lollycopter I remember accidentally turning on an empty kettle (I thought there was water in it left over from earlier, but I was wrong), and the result was... a bit of unpleasant smell (like burnt plastic), but it turned off quickly, and there was no permanent damage from what I can tell. I've heard though that some kettles have a safety that - once it goes off - needs to be replaced before the kettle can be turned on again. For reference, mine kettle was a small, super cheap Sencor one, that's mostly made of plastic.

@jamie123b

5 ай бұрын

@@adog3129you’re clearly not British then haha. Not one British person in existence to not use a kettle regularly

@8:45 You'd need a thermal camera to compare the temperature at the bottom of the kettle - or an array of calibrated digital thermometers in the base of the kettle. Compare the transmission of heat (conduction/convection /radiation) between a kettle of water and a kettle of alcohol. A surprising set of challenges for a seemingly simple measurement! 👍

Very entertaining. Really loved the video!

Low key one of the best videos on KZread