Take one.
Shall we?
Take a minute.
Look around you.
You probably never think about it,
but we are living in a time of incredible ingenuity.
Our lives are filled with fiendishly clever bits of tech
that basically make the modern world tick.
The problem is, we're now so used to these devices
that we have forgotten to remember how clever they are.
ROBOTIC VOICE: I don't have an answer for that.
I'm Professor Hannah Fry,
your hammer-wielding tech curious tour guide...
Woo!
..to the secret genius of everyday objects.
There is one law of physics that you need to know.
In each episode...
Whoa!
..I will take one seemingly ordinary item...
Woo! Immediately smoking.
..and I'll look at it in frankly...
Yeah!
..obscene detail...
Two googly eyes.
It has 180 degree view.
..meet the people who helped make it...
This is the very first air fryer.
..and follow the twisty-turny journey through the history
of its invention.
BBC VOICE: If you overshoot the turning point, don't try to do this.
It's wobbly, Johnny! Yeah, it's just wind.
This time, it's the air fryer.
I'm Hannah Fry, right? I was literally born to do this.
OK, confession time.
I resisted the first several waves of air fryer craze,
but I finally relented.
And now that I own one, it sort of has grown on me.
I do actually cook with it pretty much all the time.
I don't think anybody expected this new device to come along
and completely revolutionise the way that we prepare food.
So how did the accidental creation of a wonder wire in the 1900s...
Ooh, look at that little flame.
..a Navy officer's fight for a hot dinner in the '40s...
You made an oven!
..and an inventor with a packet of fags in the '00s...
And we all started blowing the smoke up the machine
to see where the smoke went.
..all lead to this modern marvel that's taken over our kitchens?
Ooh!
Burnt cheese.
15 years ago, air fryers didn't even exist.
Ever feel your old range is ready to fall apart?
If so, it couldn't happen at a better time than right now.
And yet today, they're in one in three of our kitchens.
200.
From Ninjas to Tefals to Towers,
we've all gone a bit nuts for these little ovens.
I'm in the Netherlands to go behind the scenes at Versuni,
makers of Phillips air fryers.
They launched the world's first air fryer
back in the cookery dark ages of 2010.
Sorry, are you torturing chips?
In their Innovation and Development Centre,
food is scanned, sliced, and stabbed.
How many broccoli do you reckon you've scanned?
An embarrassing amount.
By analysing every conceivable aspect of food,
the team here is constantly improving the way their air fryers
cook and crisp.
We have two cameras here, so we take pictures
and we predict how well cooked these fries are.
It's no wonder there's so much tech tinkering.
Given the appetite for these clever cookers,
the air fryer market recently hit $1 billion.
I had no idea that there was a place in the world where people cared
about cooked fries this much.
But how do these machines actually work?
We're going to take apart the air fryer and look at everything
from the heating element to the slippery non-stick coating.
But we're starting with the whirling wheel that blasts air,
crisps your chips, and browns your baked goods - it's the fan.
Do you love fans? I'm absolutely a fan of fans.
That is Emiel Koopmans,
fluid dynamics guru and generally just the man with a fan plan.
And our air fryer fan is quite the speed demon.
So in this air fryer, we have a flow rate of about 40 to 60 litres
per second. That is 40 to 60 bottles of milk
going around the appliance every second.
So you need quite some force to do that.
And with this rotation,
the tip of the fan is rotating about 80km per hour.
OK, so you've got 60 litres of milk being chucked at it,
about the same speed as you would do on the motorway.
Exactly. Amazing!
This is the best description of cooking I've ever heard.
But the secret to the air fryer's fantastic success
isn't just about creating a load of hot air.
It's not about just adding a fan and you're done,
but also on how the air flow is really inside the appliance
and how we push the air through the food.
And the way to achieve this is a quirky design feature.
So this is our Starfish technology.
Oh, hang on. I mean, I'm no marine biologist, but...
Starfish have five arms.
This one's only got four.
Yeah, I'm not one would have thought of naming it.
It may not be anatomically correct, but apparently,
it is aerodynamically sound.
This is very effectively pushing the air through the food.
It makes sure that it's evenly distributed.
This moulded metal design redirects the air being blasted down
from the fan.
The air's coming down here, and then you're, like, coaxing it,
saying, "This way, guys, come this way, come this way." Yes.
It's also generating a kind of tornado inside your air fryer.
Of course, it's tricky to see that invisible air tornado,
but I'm sure Emiel has a super scientific demo up his sleeve.
So I have stars here, and I have two air fryers... Lovely.
..one with a flat bottom and one with a starfish. Mm-hm.
I will turn on the one without the starfish. Mm-hm.
Glitter tornado!
We still have a glitter tornado, but the stars remain at the bottom.
Yeah. I mean, it's not coming up the sides at all, is it? No.
Let's try that again on the machine with a starfish inside.
Oh, that IS different!
And you can literally see it happening there.
You can literally see them getting pushed up and then spun.
The arms of the starfish act like ramps, pushing
the hot air through and around the food and the chamber.
Would you actually notice a difference if you were cooking?
Yes, you would.
If you do not have that starfish, then parts will be burnt,
possibly, and parts will be raw.
Many makes of air fryer will have their own
clever flow features, all driven by a powerful fan,
but how can blowing air create crispy fried food?
Time to take this thing apart.
Oh, welcome to my kitchen!
This is the scene of many a culinary crime.
But today, I'm going to be taking apart this guy.
Maybe gently, maybe less so.
We've got some obvious screws to start with.
How much of my life has been spent just undoing screws
while people point cameras at me?
Oh, there we go!
OK. Don't see this stuff on the other shows about air fryers,
do you? Hmm, Jamie Oliver?
Sitting just behind the heating element in your air fryer
is this little guy.
This is why the food gets nice and crispy. Crispiness,
it's all down to how quickly you can remove the water from food.
Ready for some frying science? In a deep fat fryer,
it's the hot oil doing all of the crispy crust-forming magic.
It gets into all the nooks and crannies of the food
and literally boils and evaporates the water.
And it's that super-fast process which creates the crunch.
But in an air fryer,
it is the movement of hot air that is doing this job,
and the fan is circulating the hot air around the chamber,
whipping the moisture away from the surface of your food
and leaving it nice and crispy.
So, newsflash, air fryers don't actually fry.
They use convection like a regular fan oven, but the fan spins
much faster in a much smaller space, so a vortex of heat can dehydrate
and crisp the surface of the food.
But where did these whirling wonders in our ovens come from?
Well, we have been big time fan fans for centuries,
but to find out how the fantastic fan began to be used for cooking,
we've got to join the ranks of the US Navy.
It's the 1940s, and troops are crisscrossing the globe.
NEWSREEL: And so a score of tired guys pile in to sleep on mail sacks
and crates for another few thousand miles to home.
Life in the sky wasn't exactly glamorous.
The planes were really cold and so was the food.
But one Navy vet was on a mission to make things better.
Enter William L Maxson.
So this guy Maxson, he has this really interesting life.
After he leaves the Navy, he sets up this company inventing all kinds
of bits and pieces for the military. He's got machine gun mounts,
he's got really complicated aerial navigation things,
but the thing that he cares about the absolute most,
the thing that bothers him,
is that the troops can't get a hot meal in the sky.
So Maxson decides it's high time these military meals got a makeover.
He needed food that wouldn't go off on the long flights,
and he had a brainwave.
If he could freeze the food first and then reheat it at speed
in the air, he'd have hot mile-high meals in no time.
Frozen dinners had not been invented at this point.
He was a real trailblazer. Yeah.
That is Ruth Amos.
She's invented more things than you've had hot dinners.
Now, ovens back in the day were big, big ovens.
And so Maxson thought, "Hang on, I want to have a go at building
something that was smaller, a bit more compact,
"and cooks food quicker." And so his thought was,
"Why don't I just put a fan in the back of the oven?"
Now, he's one of the first people to do that.
This was decades before big fan ovens would make an appearance
in our kitchens, and so adding a fan was a ground-breaking move,
allowing him to cook in-flight meals fast.
And Ruth was absolutely delighted when I asked her to slip on
Maxson's gloves and literally build his oven herself.
So I've taken the patent,
I've had a go at making one, and I've not cooked anything in it.
Literally all I've done is took this, built it,
and hoped he knew what he was talking about.
Right, Ruth. Get your oven out for the troops.
Are you ready? Yes. Ta-da-da!
It looks proper, Ruth! It could belong to an airline.
Maxson dubbed his oven the Whirlwind because its design centred
around one thing - whirling wind.
So the fan at the back is the thing that completely changed it.
So there's a fan with a motor,
the air goes through, out the sides of the fan,
past the heating elements, and this door has got that weird
shape on it to direct the air back round.
So his idea is that you cook the food quicker and more evenly
by having that airflow going round the food.
And for dinner... How do you like your steak?
Erm, white with frost on it.
Perfect!
Ruth has lovingly recreated some of Maxson's actual first frozen meals.
Oh! Burger and beans!
That well-known combination of burger and beans.
Shall we put it at the bottom?
How many people are there on this plane? OK...
Oh!
Right, let's get cooking.
It will... So the elements are at the side.
Can you feel the heat? Ooh, yeah.
Ooh, and I can feel it blowing. Yeah!
It's working!
Whether it cooks or not, there is definite airflow.
After just 20 minutes,
Maxson's sky food is starting to smell pretty tasty.
Oh, my word! Go on, give it a go. Give it a go.
OK. There's no smoke. Ooh, no smoke!
HANNAH GASPS, LAUGHS
You've just cooked dinner! Shall we eat?
I am genuinely shocked. You made an oven!
Is it properly cooked?
That's fine!
That is fine! That's fine! The bar is low, but that is fine.
It's cooked. It's chewy as hell!
There's a reason I'm in the workshop, not the kitchen.
The veg is good. I'm not joking. That actually is really nice.
It's really nice!
And luckily, the troops agreed.
The Navy started packing Whirlwinds,
and commercial airlines jumped on board too.
NEWSREEL: Each dinner hour brings pleasant relaxation.
But it would be another 60 years before Maxson's fan technology
would turn into the air fryer...
..all thanks to a frying Dutchman.
I'm Suus van der Weij.
My dad's Fred van der Weij, the inventor of the air fryer.
And that makes Suus the air fryer heir.
Fred sadly passed away in 2022,
but back in the early 2000s,
he was constantly cooking up new ideas in his garage.
So I called him the Nutty Professor.
He's an inventor, so he's all over the place.
But a quick chinwag in 2006
changed the course of his entire inventing career.
My neighbour came around, they started talking about fryers,
like deep fryers and how dangerous they are.
And that's when he was thinking, like, "Maybe this could be safer."
Fred became totally obsessed with creating a way to cook delicious
crispy fries without the danger and calories of hot oil.
His first step was creating a fan-powered prototype.
Well, this is the very first air fryer.
This is the huge wooden monster that my dad built.
You can see here,
this is how he made it with aluminium and chicken wire.
Fred dubbed his chicken coop cooker the Frites Air
and used it to make mountains of fries for the family.
Oh, they were terrible!
So they were coming out, erm, still a bit frozen,
but the tips were burned,
and they were all sweaty and kind of floppy-ish.
Even with the fan, Fred wasn't getting the right airflow,
and his frites weren't frying evenly.
He needed a way to see what that air was up to.
My dad and his colleagues, they stood in a circle
around this big machine, and got as many cigarettes
as they could in their mouths, and all started, er,
blowing the smoke up the machine to see where the smoke went
and see if the technology works or not.
And the result of all of that...finessing
was the first iteration of Emiel's four-armed starfish.
This is the very first idea of the rapid air technology,
the cross.
All of Fred's time, energy, and money went into refining
his fryer designs.
It led to a lot of fights in the house.
And, er, I believe at some point I thought he was just
living in the garage. He couldn't lose faith.
That was the whole thing.
He was betting on this horse and this horse alone,
and we don't have anything else,
so we need this horse to win the race.
But after four years and near bankruptcy,
Fred perfected the Frites Air,
and started pitching it to manufacturers.
Dutch brand Phillips loved it and bought Fred's patent.
I remember exactly when he got the news.
He came out of the garage with tears in his eyes, he said,
"They said yes, and they wired the first amount.
"And we don't need to sell the house and we don't need to..."
And we're... Getting all emotional thinking about it,
but, er, yeah, we all... There was this, this...
..this weight coming off our shoulders.
But Phillips did make one pretty big change - the name.
He came home and he said, "Yeah, so it's not the Frites Air.
"No, it's the air fryer." I'm saying, "Air fryer?!
"What kind of name is air fryer?" You know.
After going on sale in 2010, Fred was able to watch it steadily
grow in popularity before he passed away.
I'm really proud. Yeah.
Yeah, and I can't wait to tell my kids that their grandad invented
the air fryer.
Since Fred's first cooker hit the shelves,
around 80 million air fryers have been sold.
And at the heart of every single one is a powerful fan.
And for Mr Maxson and Fred, that's a pretty fantastic legacy,
if you ask me.
All of that air gets our food crispy, but the fan would be nothing
without our next component.
It's the wire that punches above its weight to pump out heat
and cook your food super fast - it's the heating element.
I'm back in the Netherlands with more weighty questions.
What's the weirdest thing you've ever cooked in your air fryer?
I tried to grill a watermelon.
Nice experiment, but I would say don't do it at home.
That is Dr Tim Van de Graaff, generator of air fryers
and novel fruit-based recipes.
Whether it's chips or chocolate cake,
air fryers can cook in roughly half the time of your conventional oven.
Tim wants to show me how that speed starts with one thing - fast heat.
My favourite thing about this set-up is that you've got the type of clock
that you would expect to see at the 100m final in the Olympics!
Because I want to show you how rapid this heating element...
It goes from normal temperatures up to 400, 450 Celsius
in only a few minutes.
OK, it's the Heating Element Temperature Olympics.
All right. One, two...
..three. OK, so already at 11 seconds, the heating element
is at 42... 50 degrees.
OK.
We are up to 80, 90 degrees.
So it took let's say 24 seconds to get up to boiling.
That's incredible. Mm-hm.
The heating element is already hotter than you would want food
to be. 220 degrees. Because this heats up the air,
and the air flows down around the bucket
and then reaches the chicken.
So with 450 Celsius, you can cook at temperatures about 200.
Now, this heating element is very similar to the one in your oven.
They both heat air that then cooks your food,
but your air fryer cooks faster because there is a far smaller space
to heat up, so the heat gets into your food quicker.
And thanks to this speed, an air fryer uses around half the energy
of an electric oven, benefiting both your plate and your planet,
depending on the size of the meal, of course.
Kind of tough to cram Christmas dinner into one of these.
If I was to cook this in a normal oven, I would give it
at least 40 minutes. This will be around 20, 25 minutes.
I mean, that's like a factor of two. Let's take it out.
OK, deal. Deal.
So that was 20 minutes. I'd eat that.
I mean, I would say perfectly cooked,
but it's got no salt or pepper on it.
I think I'll skip lunch.
Time to head back to the kitchen for some hot to trot physics.
So this right here, this curly-wurly wire, this is your heating element,
but the most important part is actually hiding inside.
Excited? Good. You should be.
The important part. Look at this!
Ooh, there it is, the crucial bit.
The heart of your air fryer is this teeny, teeny, teeny, tiny wire.
Look how skinny it is. I mean, that is pretty amazing, isn't it?
Right, that it's like 250 degrees almost instantly,
and it's this almost laughably small wire that's doing all the work.
And that is no easy physics feat,
let me tell you. It requires a special metal,
a wire with a bit of welly, as it were.
It all comes down to a very particular metal alloy
called nichrome, which of course I keep in my kitchen drawer
in a wild tangle.
Just shove that back in. That's fine. Here it is.
Nichrome has an extremely high resistance...
OK, a bite-sized bit of physics.
Resistance is how hard it is for electrons,
those teeny tiny charged particles which carry electrical energy,
to travel through a wire.
Every time you wire up an electrical circuit,
you're creating a path for those electrons to flow.
But if you use nichrome wire, it's a real struggle
for those little electrons to work their way along that path.
As the electrons move along, they bump and they bash
into all of the atoms and the ions in the way,
and those collisions create heat, which you can see quite neatly,
if you connect this up to a power source.
Imagine those little electrons are trying really hard
to move through an incredibly crowded room.
Let's snip off a little bit of this.
It's difficult to pass through without crashing into other
particles, and it's this jostling about, this resistance,
which turns the electrical energy into heat.
Let's have a little look.
As soon as that electricity starts flowing,
we should see that heat in action.
Ooh! Immediately smoking! Did you see that?
Oh, my gosh! Look! How extraordinary!
There we go. Look at that. Red hot!
That's hot enough to, air fry your food...
I would say this is slightly riskier than just using a lighter.
..or dangerously set things alight in my kitchen.
SHE GASPS
Do you reckon I can singe a bit of paper?
If I set off my fire alarm...
Is this a stupid idea? Probably.
Just, like, cuts through it.
Oh, look at that little flame! Oh, that is satisfying.
OK, I think I'm going to turn this off before I burn down my kitchen.
But not every metal is suited to the job of cooking your dinner.
Now, copper has an incredibly low resistance,
and that means there's no bumping around that causes heat in the wire.
And that's perfect when you are wiring things in your house.
You don't want to spontaneously combust your kitchen
every time you turn a light on.
If I put some electricity through here now...
OK. There's no smoking.
There's no candle lighting. And in fact, apparently...
Oh! You can touch it. It's completely cold.
From the big beefy wires in your grill
to the dainty ones in your toaster,
nichrome heating elements are everywhere in our kitchens.
But to find out exactly where they came from,
we've got to take a trip down cooking memory lane.
So first man, or maybe woman, made fire and gave cooking a whirl.
NEWSREEL: When he did, the results were chancy.
Partly raw, partly burnt, smoky, covered with ash.
Sounds like a Fry special, to be honest with you.
By the 13th century, he had pots and ovens.
The improvements went on over the years.
Early stoves just burned wood and coal.
But then in the 1880s, the first gas-fuelled cookers came along.
I assume, sir, that madam will wish to replace this kitchen range
with a modern gas stove. Oh, Richard, do let us.
I am told they are really a quite wonderful invention.
But a couple of decades later, a crazy chemist would turn
to electricity, and cooking would never be the same again.
It all begins in 1905 with this dapper Yank
and metal obsessive, Mr Albert Marsh.
Let's call him Bertie.
This is about the time that everyone is getting really excited
about the new kid on the block, electricity.
And Albert Marsh has this idea.
He thinks it should be possible to convert heat
into electrical energy.
Spoiler alert - this ambitious science project
isn't what would make our Bertie rich and famous.
He sets out to create a new metal that could withstand such
high temperatures, it would literally start an electric spark.
So Marsh starts experimenting, getting different metals,
mixing them together, and it's difficult, because lots of metals,
they get up to high temperatures, they end up melting,
they get too soft, they disintegrate.
Other metals, they oxidise, they get too brittle, they end up cracking.
But one day, Bertie tried a new recipe,
mixing together two metals with very different properties.
The first of which is nickel, which is very common at the time,
but also another metal called chromium.
Now this stuff, you find it in pigments for paints,
but also in agents for softening leather.
But very specifically, he tried a recipe which was 90% nickel
and 10% chromium.
You know what? Today, I'm going to put on my big boy Bertie Marsh pants
and try and make some of this myself.
First, weigh out your ingredients,
then add heat.
Have a look.
Whoa! That's bright. Whoa! That's bright! Exactly.
Stir continuously.
Oh, my God, this is so cool! It's red hot.
It's swirling in that dish,
and it is really a thing of great beauty.
The recipe is ready.
And after five minutes cooking... voila.
Ooh, wow!
SHE GASPS
Oh, my goodness!
Bertie's brand-new metal was strong and didn't oxidise, but crucially,
it was still pliable enough to stretch.
And so Marsh painstakingly spun this stuff out into a long, thin wire,
at which point
he noticed that it had some quite surprising properties.
When you put electricity through this,
it has phenomenally high resistance,
which means that it gets very, very hot,
and yet it neither melts nor becomes brittle.
It was a moment of triumph for our Bertie,
just maybe not the triumph he'd been aiming for.
He'd wanted to turn heat into electrical energy,
but here he'd found the substance that could turn electrical energy
into heat.
He decided to call it Chromel,
and in 1907, he patented a new device, a portable stove,
which had coils of this stuff inside as a heating element.
He said in the patent that it could be adapted for use
as a toaster.
That's right, Bertie had basically invented the first-ever toaster.
Now, you would think, given that this was literally the best thing
since sliced bread, surely he had made an absolute fortune.
But actually, the patent kind of went a bit unnoticed until 1910,
when General Electric released a suspiciously similar portable stove
that used coils of this special metal alloy inside.
So Bertie sued the big boys of the electrical world, and won.
And then old Bertie Marsh sailed off into the sunset,
surrounded by an infinite number of perfectly toasted slices of bread.
Hey!
From then on, things really started hotting up.
Is it good?
By the 1940s, our homes were starting to fill with
hot new gadgets that used Bertie's Chromel heating element.
Woman's work is never done.
"Stuff and nonsense," says the electric washer.
"It's not true," says the electric iron.
"It's ridiculous, "says the electric toaster.
"Crazy," says the electric fire.
Yeah, OK. Pipe down, electrical appliances.
Your arrival didn't exactly abolish the patriarchy.
Gracious, no!
Bertie Marsh's nickel-chromium mixture became widely known
as nichrome. Sound familiar?
And it's this tiny hidden heating wire
you can still thank for your hot dinners today.
Our next component is the slick, slippery surface inside
of our air fryer.
It's the non-stick coating.
Let's get a grip of this slippery stuff.
The inside of an air fryer is coated in a very particular resin
called polytetrafluoroethylene.
That's PTFE for short, or Teflon.
It's very clever stuff.
You see it on a lot of kitchenware,
and it is there to make cooking and cleaning a lot easier.
Now, broadly, I consider the phrase "non-stick" to be a challenge,
rather than a statement. I am very good at cremating food.
But PTFE always seems to do what it says on the tin,
even against my superior burning skills.
So, to show you just how non-stick this stuff is,
I've brought along an extremely sticky assistant.
So this is little George.
He's a gecko.
Don't worry. I'm not going to air fry George.
These little guys are the Spider-Men of the lizard world.
Come on, mister.
They literally stick to everything,
even this pane of glass.
You can see he's quite happy sticking on it.
Look at that. Do you see? Quite happy to just climb up glass.
Now, the reason why George is able to stick on to this glass
is because he has these tiny little microscopic hairs
on the bottom of his feet.
The molecules of those hairs interact with the molecules
of the glass, and it creates an electromagnetic attraction,
allowing him to seemingly climb the impossible.
Now let's see how the stickiest guy in town fares against my PTFE.
Are you ready, baby George?
Let me just show you this.
Little guy!
Ooh! Oh! Bless him!
Now, the reason that George is having trouble here
is because of the chemical structure of Teflon
means that that same interaction doesn't happen.
He's got no grip, and he's sliding down. Oh, mister!
I think we'll stop there for you.
But to understand exactly what's happening at that microscopic level,
first you have to understand where PTFE came from.
Let's journey back to the dark times.
ADVERT: Remember way back when,
when eggs used to stick to the frying pan,
when almost everything used to stick to roasting pans?
The era before non-stick pans.
The story of Teflon's discovery is one of those great ones of science.
It was a complete accident.
That's our materials girl, Dr Anna Ploszajski.
Right, Anna, let's head to the 1930s.
It was a very young chemist called Roy Plunkett who was working
at a company called DuPont.
Back then, the refrigerant gases that they had to basically
make things cold were nasty, toxic, smelly,
so he was working on safer refrigerant gases.
Trying to find a better alternative. Exactly.
Then one fateful day, Roy arrived at work
and, well, changed the world.
One morning, he opened the valve to a gas cylinder
and nothing came out. And he thought, "That's strange.
"I know there's some gas in there."
So he took the gas cylinder off, sawed it in half...
Of course. ..to open it up. Classic.
And inside he found not a gas, but this kind of powdery white
solid material, which was unexpected. Yeah.
Sure, Roy's gas experiment was ruined,
but it turns out he'd actually created a brand-new plastic.
Brace yourself, people, it's hardcore chemistry o'clock.
In their gas cylinder was tetrafluoroethylene,
this refrigerant gas, and the molecules of that look like this.
There's two carbon atoms,
and on each of those carbons, there are two fluorines. OK.
But they think the iron in Roy's canister, under high pressure,
kick-started a chemical reaction that turned the gas into a polymer,
a long chain of molecules.
So it's now many molecules all bonded together. OK.
So this is tetrafluoroethylene,
and the white solid is polytetrafluoroethylene.
PTFE. PTFE. Mm!
And this specific chemical structure gave this new polymer superpowers.
This fluorine carbon bond is very, very, very strong.
Because of the chemistry of it,
it means that these love bonding together,
and they love bonding together so much that actually
they're not really interested in anyone else. OK.
So if you're a water molecule, say, you come along,
say, "Can I come and sit with you guys?"
Right, these are the mean girls.
They're like, "You can't sit with us."
This chemical rejection makes the material non-stick.
Now, this chemistry dance is all happening at the nano level...
So I'm just going to make a little water droplet.
..but we can see it play out using just a macro lens,
some water, and a pane of glass.
And what I want you to notice is the shape of the droplet.
Yeah. It's like, quite, flat. Yeah.
In fact, the water wants to spread over the glass.
And so they... They love each other. They love each other.
They're having a great time.
But do the same thing on PTFE...
Oh, wow! Look at that!
It's nowhere near as spread out. Exactly.
It's much more rounded. It's sort of beaded up. Yeah.
And this is because the water doesn't want to stick,
so it's trying to reduce the surface area underneath.
So it's... Yeah, it's sort of sucking itself into a little ball.
And this is all down to the molecules on the surface?
Yeah. Those mean girls.
In 1945, DuPont renamed their wonder material Teflon.
Teflon has been characterised as a lucky accident,
an example of serendipity, and a flash of genius.
It would go on to be used in everything from space shuttles
to raincoats.
New fibres with new benefits that never existed before.
And in the 1950s, it made its way into our kitchens.
I've got great news for you.
And it's right under this macaroni and cheese.
It didn't melt or corrode.
It was super durable.
Right on, Miss Teflon Two.
And of course, non-stick.
# Don't make a meal without that seal... #
A complete cooking revolution, all thanks to Roy's happy accident.
And I was introduced as God's gift to the housewives.
Well, hold up right there, Roy!
I'm afraid it hasn't been total smooth sailing for Teflon
in the 80-odd years since your invention.
See, although today's Teflon is deemed safe to use,
it comes with a bit of baggage.
In the 1980s, it came out that the chemicals
used to make PTFE could be toxic.
Despite changes to the manufacturing process to make it safer,
the stuff has remained controversial.
So ARE we safe to air fry?
Are you at risk when you're cooking with it, then? No, completely not.
That is Dr Ted Pajak
from research and development
at air fryer makers Versuni.
Because as long as you use it according to its application,
it's absolutely perfectly safe.
200... 20 mins.
Basically, unless you find a way to override your air fryer
and get it to some seriously hot temperatures, or just, you know,
explode it, you should be fine,
because it's only under these extreme conditions
that the more harmful chemicals
used in the making of non-stick coatings are released.
But that is not the end of the story,
because the making of Teflon is still problematic.
We realised that the chemistry out of which PTFE is made
is actually ever living in an environment.
So this is the forever chemicals that people talk about.
When the chemicals used to make PTFE get into our water systems and soil,
they've been linked to health problems like decreased fertility
and cancer, so much so the EU is considering
banning the manufacturing of PTFE.
The direction is to introduce a ban, timeline somewhere from 2027.
And so that includes all of the sort of PTFE Teflon coatings.
More than that, all cable insulations, greases, electronics,
everywhere where you want to use the substance
that actually repels liquids.
So Ted and the team are already looking into alternatives.
His front runner is a new type of ceramic coating,
the recipe of which is top secret.
We strive that you actually get the same properties as for the user
as you would with a PTFE coating.
We will need to wait to see which non-stick ideas stick.
But for now, the research tells us we are safe to fry with PTFE.
Our next component has totally transformed the way we live,
and without it, there would be no air fryer at all,
or, well, any other electrical appliance, for that matter.
I'm talking about the three pinned hero that gives our air fryer life.
It's the plug.
Our kitchen countertops are already pretty packed, so a lot of us
keep our air fryers tucked away when they're not being used.
And the reason why that is possible is because of
the humble British plug, specifically the BS 1363.
Now, doesn't get a lot of attention, this guy.
But over the next three minutes, I hope to persuade you
that this is a genuine genius invention.
To get to grips with the UK plug's unique engineering,
let's get inside.
Well, you've got a fuse there.
You've got two wires, live and neutral,
that are essentially closing the circuit,
so that electricity will flow into and out of your electrical device.
I have an esteemed friend and colleague
who says the live is brown, because that's the colour
your pants will be if you accidentally touch it.
But the clever bit is this third wire up the top,
the green and yellow one. This is your earth wire.
This is the wire that allows the electricity an easy way to escape,
should anything ever go wrong, so you don't get electrocuted.
And the plug has been designed to put that earth wire
front and centre.
I don't know if you've ever noticed this, but the top pin,
the special third pin,
this pin is ever so slightly longer than the others.
That long earth prong goes into the wall first,
so that your plug is earthed before it ever becomes live.
An abracadabra opens up a magic plug portal.
You see, the entrances to the live and the neutral points are protected
by these little gates.
So even if you sort of try and poke a pencil in there,
you're not going to be able to get to them.
This gate gets in the way, and that gate is only opened...
..when the top pin pushes through.
And then, just a little spring allows that gate to open.
Do you see that?
Very, very clever. Extremely clever idea.
And thus ends my shameless plug for the British plug.
To find out how we got the super-safe British plug,
we need to go back to a perilous time when our homes
were basically electrical minefields.
It's the 1880s, and some lucky ducks,
or rich fat cats, were getting hooked up with electricity
in their homes.
TV ANNOUNCEMENT: This was the beginning of widespread use
of electricity.
But those first fancy electrical appliances had to be
screwed into the light socket for power.
The downside of dangerously daisy-chaining cables
from the ceiling were some serious electrical shocks
and occasionally, you know, death.
To try and make things safer, various inventors came up with
new plug designs for the walls or lights.
But that meant, by the early 20th century,
there were a load of competing plug styles,
and electrical incidents were still shockingly frequent.
It would take a courageous female engineer to finally sort out
this safety nightmare.
Oh, my...
Look at her, right at the front!
It doesn't look like a particularly fun party, let's be honest.
I mean, at least 20 men, and then one absolute badass
sat right in the middle.
Allow me to introduce you to a feminist engineering icon,
Caroline Haslett. Here she is.
Now, back in 1925, when electricity was still kind of
quite a new thing, really,
she was this young, inspired electrical engineer.
And she managed to buy herself a swanky new flat in Marylebone,
and she decided that she was going to install the electricity herself.
This was not the go-to pastime of your average 1920s gal about town,
but Caroline was anything but average.
She strongly believed that the new-fangled electrical appliances
of the day could transform women's lives
by freeing them from the horror of household chores.
The thing is, around this time, people were pretty confused
about electricity, and understandably so,
because some plugs would have three pins, others would have two.
This one here I think is made of wood.
Seems like a slight dangerous idea.
And, I mean, look at the absolute monstrosities that were available.
I'm not sure how you're supposed to comfort yourself nice and warm
while you're sat next to a plug socket in the wall.
But, Caroline, she wanted to change all this, so she set up
the Electrical Association for Women with the amazing slogan
"emancipation from drudgery."
And then she spent two decades encouraging women to get on board
with the electrical revolution...
..which brings us to the aftermath of World War II.
The mammoth job of rebuilding Britain offered a golden opportunity
to redesign our dodgy electrical system.
So the government formed a committee of mechanical engineers
and appointed Caroline as the safety expert and, you guessed it,
the sole woman.
So they spent an entire month plugging away,
and came up with this thing here, the so-called
Electrical Installations, Post-War Building Studies, Number 11.
Very catchy.
Within its many pages was something Caroline had really pushed for,
a safer universal plug.
Now, before this point, every single electrical item had to be separately
wired into a fuse in the wall,
but by putting the fuse inside the plug,
it meant that if anything dodgy, like a extremely terrifying electric
hot water bottle, if anything dodgy failed, then it would be the plug
that would bear the brunt of it,
rather than blowing the electrics in your whole house.
In 1947, the now iconic three-pin model
became the standard British plug, and the same year,
Caroline was made a dame for her electrifying work.
This might have been a product of post-war design, but the thing is,
this has remained pretty much unchanged for the last 80-odd years
or so, and I think that is a testament
to its simplicity and perfection.
Today's plug may be perfectly formed,
but perhaps not always perfect in practice.
They do occasionally have the capacity to drive you,
well, up the wall, so you may not feel too bad about the fact
that back in the Netherlands, someone is actually being paid
to punish plugs.
Do you ever test it to its limit? Do you ever, like, really load up?
Yeah, we'll keep doing it till failure sometimes.
That is Imogen Adams, engineer and low-key plug torturer.
She twists, rips, and pulls your plugs to make sure
they can withstand everything you throw at them.
Why is this relevant for an air fryer?
So in your kitchen, you might not have that much countertop space.
That also means that you might be unplugging and plugging a lot.
Yanking it accidentally. Yeah, or tripping over,
Sure. I have definitely done that before.
So we want to really make sure that these are as safe as possible.
But Imogen and the team are looking into making this brutal air fryer
plug treatment a thing of the past.
So here we have a new prototype we've been working on,
and it's actually cordless.
Hold on, sorry. It doesn't have a plug at all?
No. You can lift it up.
And it's not battery powered? It's not battery powered at all.
I promise.
MOTOR SWITCHES OFF
Did you hear it turn off? That's hilarious.
BEEPS
Yeah.
Then it works again, and we can cook our food in it again.
That is very cool!
Instead of your appliances all vying for socket space,
Imogen's aim is to make them all completely cordless.
You know, like, when you charge your phone wirelessly... Yeah.
..is this, like, a big version?
Exactly. So it's working in principle in the same way,
just with the wireless power transfer,
so we have embedded inside the workbench
some transmitter coils, like here. Mm-hm.
So what is this? Just a coil with electricity going through it?
Pretty much, so the transmitter's hooked up to a power source
or a battery we have here. OK. And then we have a receiver.
And then when the power is going through the transmitter,
it creates an electromagnetic field that then the receiver can pick up.
Show me.
SHE GASPS
It's like magic, except it's just physics! Yeah!
Science is cool.
OK, so it wouldn't be an entirely plugless utopia.
You would still need one sneaky plug to power your countertop,
but it would make for a cleaner, clearer work surface.
Is there going to be a point in the future where I can just
pop down an air fryer and pop down my phone
and pop down whatever else?
Yeah. Each device can talk to the transmitter and the receiver,
and they can say, "I need this much power."
So you could put a blender on, which might need less power
than your air fryer.
The team here are just in the early stages of development.
Oh, hello! Oh, do you know what? That looks...
That looks pretty perfect. That...
I mean, there's a slight smell of prototype.
Yeah. That comes... It comes in R&D.
We're not going to eat this, but... No, but no wires, though!
And it's not just air fryers.
The entire wireless charging market is predicted to rise
by over $30 billion by 2030.
In just a decade and a half,
air fryers have changed the cooking game, but the next big breakthrough
might mean you can do dinner without even lifting a finger,
because the future is an all-seeing, all-sensing frying machine.
I like to keep up with the latest inventions on Blue Peter,
and I've got something here that may well turn out to be
the kitchen of the future.
For years, we have been promised futuristic kitchens...
A magnetic field, not magic, keeps the frying pan in air
and breakfast cooking.
..and high-tech devices designed to deliver us from the drudgery
of everyday dinner making.
I'm back at Versuni, where they're working on the air fryer
of the future.
You're the one who gets to come up with the crazy ideas
and see if they're possible. Yes, yes.
That's Shanghai-based engineer and high frier Winnie Sun.
I'm working to develop a smart air fryer
with computer vision integration.
Winnie has spent two years cooking up a new AI powered,
camera-wielding air fryer.
So, basically, she's given it eyes and a brain.
So the air fryer works out how to cook the food for you?
Yes. So your air fryer can recognise the food you place inside,
you will show the algorithm many pictures.
For example, the apples or oranges, bananas,
and then it will learn.
Don't let Winnie's easy-peasy AI-squeezy tone fool you.
This is fiendishly clever tech that doesn't just identify the food,
it learns how best to cook it.
It will constantly monitor the whole processes so that it can accordingly
adjust temperature and time as needed for a best cooking results.
But for the air fryer to really understand cooking,
that's no picnic.
There are just so many varieties.
For example, fries or potatoes.
You have such straight cut shape and you also have slice and cubes.
Which means Winnie has had to feed this greedy guts algorithm
every possible food shape as well as type,
so it can learn exactly what you like.
It's really like having a private chef at your service.
Look, it sounds great,
but am I just being sucked in by another pie in the sky prototype
that will never actually make it onto the shelves?
How long until we see AI cooking coming to air fryers?
In our next generation.
A couple of years. Really? Yeah.
Air fryers have only been with us for 15 years,
but they really have changed the cooking game,
so who knows what things will look like in the next 15?
Oh!
And maybe an AI device holds the key to my culinary prowess.
Finally.
Initially, I was a little bit reluctant to do an episode
on air fryers just because there's so much hype about them,
and I sort of didn't want to jump on the train.
But, you know, now I am quite fond of them because I think,
in here, there is over 100 years of scientific innovation.
There's countless people who have been inventing
with the sole purpose of making our domestic life
just that little bit easier.
So you know what? I think these little ovens
probably do deserve a place on our countertops.
Next time...
Whoa, whoa!
..it's the fridge.
Unless you are a refrigeration aficionado,
it probably doesn't get a second thought.
But it's the story of an explosive invention...
He almost blows himself up a couple of times, but it was worth it.
I feel like we're sort of matching.
..a chicken incubator and a revelation...
The problem is serious.
..that set fridges against the world.
The Open University has produced a free poster
exploring what lies behind the genius of some everyday objects.
To order a copy, call...
..scan the QR code, or go to...
..and follow the links to the Open University.