Original subtitles

Let's face it, our world is downright weird.

Oh, my!

Crawling with creatures you've never heard of.

I can't believe that's a living thing.

Full of the unexpected.

Like freak weather exploding out of the blue.

I thought I was going to die.

And rocks that spontaneously combust.

I thought it was dynamite going off.

And the unexplained.

An unborn twin, discovered inside a brain.

There was multiple hair follicles, bone and teeth.

- We've scoured the globe to bring you the very weirdest stories. - Ah!

I could feel this intense pain,

as if you were being stabbed by hundreds of syringes.

In this series, we're going to examine the evidence,

test the science and unravel the mysteries.

We're going to discover what in the weird world is going on.

In this episode,

we uncover the secrets behind some of the natural world's weirdest events.

How did this woman find herself inside a meteorological monster?

What creates a wonderland where flowers bloom underwater?

How do you extinguish fire with an invisible force?

And just why has this rat developed a death wish?

But our first strange story comes to us

via the internet, all the way from Thailand,

where a familiar creature was caught doing something unbelievably bizarre.

Have a look at this. Posted in May 2015, filmed during a fishing trip.

Looks pretty ordinary, doesn't it?

Your run-of-the-mill, bog-standard worm.

Oh, no. Are you ready?

I told you. Do you want to see it again? Of course you do.

Hand on heart, this is real. There are no special effects here.

Look, and just to prove it,

here's another example found in a fisherman's net in Taiwan.

These bizarre creatures are called ribbon worms.

And although there are over 1000 species,

most of them live in the ocean.

So, you're unlikely to cross paths with these deep sea

monstrosities, which is a relief, I suppose, unless, of course,

you are a scientist obsessed with these weird worms.

Ribbon worms are incredible animals.

They really are a unique set of worms.

You don't say.

Oh, my goodness.

Now, it's pretty obvious what sets these worms apart.

That thing spewing from their bodies is actually a kind of tongue

called a proboscis.

It's a crucial appendage, because ribbon worms are a world

away from the earth eaters we're familiar with.

Oh, no, they have an appetite for something more substantial.

Ribbon worms are predators.

They are the carnivores around in the worm world.

And what they'll do, is they'll send out this proboscis,

sense that it's something that they want to eat.

Then, game over.

And the biology behind this alarming appendage is very clever indeed.

The proboscis usually stays in a sack on top of the worm's gut,

but once the worm senses prey approaching,

its muscles contract quickly, forcing fluid into the sac

and shooting it out through a hole in the worm's head.

Imagine you've got a rubber glove inside your face which you can

blow into, so that it forces outwards.

That you can then use to grab whatever is on offer for your lunch,

before you drop it into your stomach and eat it.

It's genius.

And if being able to jettison your innards towards a target

wasn't spectacular enough, some worms have even customised their appendage.

Sometimes, these proboscis have little stylets on,

so hooks that they stab into their prey.

Some will also produce mucus which then can stun their prey.

And our friend from the first video is even more extraordinary.

Only one of two ribbon worms with a branching proboscis that most

scientists have only ever seen in textbooks.

It's absolutely fantastic and it's absolutely very weird.

I'd read about it before, but I have never actually seen any

footage of it.

Consider it our gift to you, Emma.

OK, I can see that regurgitating your insides to grab your next meal

might not be everyone's cup of tea,

but our next contender has got an altogether more refined technique.

Spiders. I suppose you could argue they're pretty weird.

They're certainly a love them or hate them kind of animal.

I'm firmly with team spider, of course.

But I think we can all appreciate that they're very clever

little creatures.

They slowly build a web...

..wait for a fly or another insect to get caught...

..and then move in for a meal, right?

Well, not quite.

Many spiders spin webs which incorporate a type of silk

which is sticky, but it's not only sticky.

It's also statically charged, so that the web

and the prey are drawn inextricably together.

Can you see the web moving towards the fly?

It's only a few millimetres, but it's just enough to make

the difference between snaring a meal and going hungry.

It's a fantastic trick that thousands of species put to good use.

But deep in the Peruvian jungle, there's one spider who's refused

to settle for the norm.

Now, he might not look like much, but just watch this.

Captured on film for the first time,

this tiny spider has designed a projectile web.

And why has he gone to such extraordinary lengths?

Well, it's all a matter of expectation.

You see, this arachnid might be diminutive,

but it has its sights set very high.

Flies... Nah!

Midges... Yuck.

This spider is only interested in fat, juicy mosquitoes.

Which is a bit of a problem.

Mosquitoes, compared to a lot of flying insects,

they fly quite slowly and are quite deliberate in their movements.

They also fly with their limbs outstretched.

It's difficult for them to become trapped in a web.

So, if they spot a web or feel it with their outstretched legs,

they can change direction quickly and this allows them

to avoid the deadliest of traps.

So, if you're spider with a hankering for a mossie,

what do you do?

The spider draws a strand of silk from the centre of its web,

stretching the whole silky trap into a cone shape, which it then

catapults with itself attached, towards flying insect prey.

That's why it's called the slingshot spider.

The slingshot ratchets back and then fires...

..colliding with prey before it's had a chance to change its course.

It's a masterful piece of engineering that makes this spider

truly deadly...

..if you're really, really small.

Now, these spiders are just a few millimetres long,

so they pose no threat at all to humans, but there is another

creature that has a far more sinister way of reaching its next victim

and it's something that we should be truly terrified of.

Have a look at this.

A rat chasing a cat.

Just look at that. Go on, get him!

This behaviour defies all the rules of nature.

And it's not a one-off case.

But this is not a new species of uber-aggressive fighting rodent.

These rats weren't born with a death wish.

No, scientists think that this bizarre behaviour might be

brought about from a run-in with something altogether stranger.

It's quite possible that these rodents aren't

acting in their right minds.

They've been hijacked.

Hijacked by a parasite.

Toxoplasma gondii,

a tiny single cell organism that lives in the rodent's brain.

Here, it meddles with the neurones

to render the rat completely fearless.

But why?

What possible benefit could it be to the parasite to give the rat

a death wish?

Well, here's the really weird thing.

This parasite doesn't actually like rats very much.

They're purely a means to an end.

You see, the ultimate aim for toxoplasma, is to get into a cat.

What is unique about this parasite, is that it can only reproduce,

it can only sexually reproduce inside the gut of a cat.

What it needs to do its life cycle, its evolutionary pressure,

its need, is to get from one cat to another cat and the question is,

how does a tiny parasite with no legs, no means of moving

on its own, how does it get all the way from one cat to another cat?

Mind control. Toxoplasma makes rats its rodent slaves.

Here's how it works.

Toxoplasmosis offspring exit the cat in its faeces.

The rat or mouse then eats those faeces.

Once embedded in the rodent's brain,

the parasite does its thing, significantly lowering the rat's

inhibitions, making it less cautious and more likely to get eaten.

Et voila. The life cycle is complete.

Toxoplasma is a very focused little organism,

going to extraordinary lengths to make sure

that this cycle is fulfilled.

The parasite doesn't only make rats less afraid of cats,

it does something much weirder.

We find that in the brains of these animals that are infected

with the parasite, it looks a little bit like these

animals are actually sexually attracted

to the smell of the cat urine.

Infected rodents aroused by the aroma are enticed into feline

hang-outs and then eaten.

The cats are kind of like love hotels for the parasite

and the rats and the mice are taxis that take them

in between each individual love hotel.

Quite a thought. And that's not the end of it.

The toxoplasma's tale is about to get even darker because,

and I hate to tell you this, the parasite can infect us too.

Here's the real shocker.

Research suggests that this parasite could be lying

dormant in the brains of one third of us.

It's truly terrifying.

Of course, toxoplasma doesn't want to be inside us. We're a dead end.

It lives trapped inside our brains and what it might be

doing in there, is, of course, serious cause for concern.

The big neurobiological question that we want to answer is, if it's

changing the behaviour of rats and mice, what is it doing to people?

Well, toxoplasmosis won't have us sniffing out cat urine,

but studies show that it might be having some very serious

and very disturbing effects on our mental health.

Around the world, studies have shown that people with schizophrenia

have high rates of this parasite.

Toxoplasmosis is able to alter the way the rat's brain functions.

When this parasite gets into people, maybe it's doing the same thing.

Maybe you can have chronic effects on something like mental illness.

If Patrick can find a link between the parasite and our behaviour,

then it would change the way we look at mental illness and,

of course, potentially help find a treatment.

And just before you lock the cat flap for good, let me reassure you.

You're most likely to get toxoplasmosis through eating

raw meat.

Fertilisers can contain a fair bit of cat faeces, so when the parasite

gets into the crops, it gets into the cows and then it gets into us.

Cook your food well, keep your hands washed

and then you can cuddle your cat free of fear.

So, toxoplasmosis, the Black Death, Weil's disease, salmonella,

oh, I don't know.

The poor old rat really does have a bad reputation,

which very much upsets me, because I'm a great fan of the rat and that's

why I'm really pleased that a small group of people are doing everything

they can to raise its reputation from the mud of human loathing.

In East Africa, there's one species that is challenging

the rodent's stereotype.

The giant African pouched rat.

This is the new hero of the rodent world.

Not pests, but highly trained life-saving specialists.

In the foothills of Tanzania,

an army of these giant rodents have been trained to save human lives...

..with just a clicker and a tasty treat.

They're not strong enough to drag you from a burning building.

That would be daft.

But they are just the right size to pull off an astonishing

feat of bravery.

Something so clever,

that you'll never look at a rat in the same way again.

But first, we need some context.

Tanzania's neighbour, Mozambique, has had a troubled past.

Years of civil war have left their mark and nearly 20 years after

a ceasefire, peaceful fields still claim lives.

More than 100 million land mines still litter the ground worldwide.

And they kill more than 4,000 people a year.

So clearing land mines safely is a pressing concern.

But how do you do it without the loss of even more lives?

Well, here is an extraordinary solution.

A giant, pouched, bomb squad.

It's not as ridiculous as it sounds.

Rats have a sense of smell which rivals dogs and, in fact, they can

smell an infinitesimally small amount of TNT from a metre away or even

when it's buried deep underground.

Sniffing out a land mine is a breeze for an African rat.

But a dangerous job needs serious training.

Which is easier than you might imagine.

Because rats are incredibly intelligent animals.

And if there's one thing they'll do anything for, it's a banana.

During a nine-month boot camp the rats are taught to

move along a piece of rope, sniffing for teabags stuffed with TNT.

They scratch to mark the spot

and then come running back to the sound of a clicker.

Mmm, banana!

Looks like this rat has passed the test.

Now fully trained, the bomb squad's job becomes deadly serious.

No more teabags.

These rats are now searching for real land mines.

Mines that are designed to activate under foot.

But these rats haven't gone through all of that training,

all of those kilos of bananas, just to sacrifice themselves.

You see, not only are these fantastic rats clever, with a wonderful

sense of smell, they're also light.

Just over a kilogram.

Small enough to go undetected by any mines below.

And look, he's found the mine.

Superb!

Now the disposal team can go to work.

In just 20 minutes, the rats can cover the same amount of land that

humans would take five days to search.

And so far the bomb squad have cleared over 13,000 mines.

Giving more than 11 million square metres back to the farmers.

The heroic African pouched rat.

Making the fields of Mozambique safe, one banana at a time.

Yes, finally the rat's reputation is on the rise.

Vive le rat!

So, an unassuming worm might be concealing a weapon.

And a tiny spider could be packing a slingshot.

Invincible rodents are really being controlled by a parasite

and creatures that we all once thought were pests are now heroes.

Come on, give that rat a medal.

For our next journey we're going from a watery wonderland to a stony

relative with a soft heart.

And it all starts in the mountains of Austria.

Dotted with quaint villages, flower-strewn meadows...

COW MOOS

..and home to the strangest lake on the planet.

Every year hundreds of people come from all around the world to

visit the Emerald Lake near the town of Tragoess.

But not to picnic by its picture-perfect shores.

For just two weeks of the year, it entices a different type of tourist.

Drawn to Tragoess by a secret that lies under the surface.

You see, something very strange happens at Tragoess.

And Marc makes a yearly pilgrimage to capture it on camera.

Bridges...

..flowers...

..pathways...

..benches...

It's beautiful but totally bizarre.

I mean, how is it possible that a place exists where fish swim

through grass and flowers bloom underwater?

These aren't sub-aquatic species.

And there hasn't been some sort of natural disaster at Tragoess.

In fact, the Emerald Lake is only part of the story

because for much of the year the place looks entirely different.

For several months the valley lies under a covering of snow.

You're more likely to see snow bums than divers.

But as the spring arrives the snow melts.

Revealing a shallow lake and some very familiar looking landmarks.

'Pretty? Well, yes. Strange, no.

'Where is our watery wonderland?

'Well, stick with me.'

In early spring, Lake Tragoess is just one metre deep.

It's a pond, really.

Diving would be tricky.

But, as all the melt-water rushes down from the mountains it

disappears underground.

Raising the water table under the lake so dramatically...

..that it begins to fill.

Until, for two very surreal weeks of the year, the spring growth

finds itself submerged...

..ten metres deep.

An underwater wonderland...

..created by the seasons.

Must be pretty confusing to be a fish there. One minute you're

swimming around in a puddle, the next minute you're in a veritable ocean.

But there is one species for which the world very rarely changes.

The Atacama Desert in Chile.

A hostile moonscape in which temperatures can vary by up

to 20 Celsius in a day.

And rain doesn't come for years at a time.

Not much survives out here.

Well, except for these.

Huge bright green blobs melting into the desert.

Despite their bizarre looks, these blobs had gone under

the public radar...

..until 2010 when a photographer with a peculiar interest spotted

a picture online.

They truly look alien. They are so strange looking.

I was definitely intrigued. I could tell right away

they were going to be very photogenic.

Inspired by these green globules Rachel embarked upon

a 10,000km journey to photograph them.

We headed up into some very high elevations and some extremely arid

conditions, so parts of the Atacama are known as absolute desert.

And here, amongst the llamas, Rachael found what she was looking for.

The first time I saw them they were visually stunning.

Stunning?

I suppose so, if pea-coloured pillows are your sort of thing.

But it certainly got Rachael clicking.

Some are bulbous, some are these very large, expansive mats.

They look like they might be soft to the touch like moss would be,

but they're not. They're a little prickly.

OK, so what on earth are these spiky, bulbous, matted mounds?

These bizarre desert sponges may look alien, but they're not.

They're very much of this world.

And their closest living relative?

The humble carrot. Yes.

The carrot.

No really, I'm not joking, the carrot.

Yes, look closely and these blobs reveal themselves as plants.

Millions of tiny flowering heads called yareta.

One of the Apiaceae family, alongside carrots, parsley and fennel.

But don't let their earthly origins or commonplace cousins

disappoint you.

Remember I said Rachael had a peculiar artistic interest?

She didn't travel all that way just to photograph any old flower.

The yareta was on her photographic hitlist for one very strange reason.

I spent about ten years working on a project called

The Oldest Living Things In The World.

Rachael had been searching for the most ancient plants on our planet.

When I heard about the yareta it was not only that it was

an unusual plant, it also happens to be old.

I saw a whole range of ages from some babies up

until probably around 3,000 years old.

3,000 years old.

That means this yareta germinated at the start of the Iron Age.

Growing just one centimetre every year since.

In a complete no-man's land.

If you're a plant, surviving in an arid desert

environment like this is actually pretty difficult.

Take a look around.

It may appear that there are lots of cacti here,

lots of drought-resistant species, but then look again.

In fact, there are very few different types of plant here.

'Cacti are one of the few species that thrive in the heat.

'Living for up to 180 years, which is impressive

'but nothing on our green blobs.'

So how does the yareta manage to survive in such a hostile

environment for so long?

It turns out that this other-worldly blob has a secret super power.

And a clue? Well, it's in the yereta's looks.

That blob shape reduces the plant's surface area.

And the tiny heads packed tightly together protect against

the worst of the weather.

And under those green heads,

the remnants of 3,000 years of growth form a cushion, storing water

and helping the plant to regulate its temperature.

It's a pretty humbling experience to stand in front of these

organisms and think about how much they've witnessed

and weathered and survived.

The yareta is a super weird, super survivor.

3,000 years - puts a lifespan of a carrot to shame.

And it's strange to think that these green blobs are related to

a vegetable we eat.

But then I suppose I'm always surprised

by what people are prepared to put in their mouths.

For our next weird event we're staying in Chile

but moving on to a very different habitat.

Imagine you're walking along the shoreline when you come across this.

You probably wouldn't give this rocky outcrop a second look.

Unless, of course, you're a local.

Because they know that there's more to this lump than meets the eye.

Gives new meaning to blood from a stone.

But this weird lump is actually alive.

It's pyura,

a filter feeder that grows in rocky clumps along the tide line.

Its hard exterior hides a soft, gooey centre that these

locals consider a seaside delicacy.

A bit like an oyster, delicious...

PEOPLE YELL

..well, apparently.

HE EXCLAIMS

Now, Chilean taste buds are one thing,

but its the lifestyle of this living rock that's truly bizarre.

It actually starts life as a tiny tadpole.

Before fixing itself in position and turning into a living rock.

Stuck fast.

Which is a problem.

I mean, how does a male rock find a female rock and make tadpoles?

Well, it's easy if you're actually male and female.

Yes, the living rock needs to look no further than itself to procreate.

Surely it can't get any weirder than

a self-fertilizing, sex changing invertebrate masquerading as a rock?

Oh, but, yes, it can.

Because our gooey geode has a backbone.

No, really, it's true. It develops at the tadpole stage.

And then compare it to,

I don't know, a human embryo.

See any similarities?

The living rock evolved this kind of backbone at the same time

our ancestors did

some 600 million years ago. Cutting straight to the uncomfortable truth.

We're related.

This super strange pseudo-rock is our closest invertebrate cousin.

It's quite hard to swallow.

An underwater wonderland created by the seasons.

A green colony that's seen centuries pass.

And our rocky relatives, unchanged for thousands of years.

And apparently, delicious. But do you know what, I think

I'll take their word for it.

Finally, we're going to get very hot and bothered

when we meet one of the world's most dangerous meteorological phenomena.

'And discover the science behind a very strange

'fire extinguishing invention.

'But first, a trip to the States.'

The Florida Keys, in fact, renowned for their long, sandy beaches,

deep blue waters, and beautiful sunny days.

But on the 25th of September 2013, a local fisherman found himself at the

centre of some very strange weather.

On that day I was out enjoying a typical summer day

with my friend Erin and we were catching lobster.

During the course of that time we had seen this cloud on the horizon.

We thought that there was the

potential for something to happen but we didn't recognise how

great an event it was going to become.

What he thought was just another cloud,

turned out to be something much weirder.

As we approached the base of this cloud it was a rapidly

changing formation.

This was something that caught us off guard

and we couldn't have prepared for.

It was a waterspout and Kevin was headed straight for it.

Look at the funnel starting on this. Looks like it's getting angry.

So what creates these strange, spinning spouts?

The basic ingredients of a waterspout are a warm water surface

and a storm cloud over the top of that surface.

All sorts of places are prone to them,

the Great Lakes of North America,

the Mediterranean gets a lot of water spouts.

They can even form in a swimming pool!

And although they look bizarre,

the science behind these spouts is actually fairly simple.

We can even make our own in miniature.

The dry ice represents warm air rising from the ocean surface.

It forms a column that draws in surrounding water and clouds.

This cloud-filled column starts to rotate,

creating a whirling vortex, a waterspout.

On a hot, stormy day

weather conditions can be ideal for making waterspouts.

Perhaps a little too ideal.

Just off the coast of Liguria, Italy, a passer-by captured this

footage of something incredible...

..twin waterspouts.

If under a particular cloud there's more than one column of air

rising at a time, then you can get multiple waterspouts.

Back in Florida, Kevin

was surrounded not by one, or even two spouts.

They're everywhere.

There's one, two, three, four and a fifth over there.

Look how fast it's spinning.

So, multiple spouts is a very real, very weird possibility.

But there is one thing crazier than a sky full of raging vortices

and that's this man.

I think we should go inside!

All right, let's go, we're going to batten down the hatches,

put on the waterproof housing and we are going inside.

Kevin was playing with fire... well, water.

There is a million decisions going on.

Can I really do this? What are the repercussions and

who's going to get mad at me and who's going to see this?

My girlfriend's going to kill me.

Aah!

Your ears pop, you feel the hairs on your neck stand up on end.

It was such a sensory overload, your body didn't know how to react

to it and your brain didn't have time to process

so the first emotion to come out was pure joy.

That opened all my hatches and everything.

Kevin sailed through a spout and lived to tell the tale.

He was very lucky, the boat only suffered

some minor damage, war wounds, really.

We won't do that again.

- And just in case you felt yourself asking... - No animals were

harmed in the making of this film.

Now, Kevin and his friend survived their adventure because waterspouts

aren't necessarily that powerful.

The vortices that he filmed weren't spinning fast enough to

lift the boat from the water.

'But when a vortex forms over land it becomes

'a very different beast altogether.'

April 27th, 2011, Alabama.

And a drive to work is about to take a very frightening turn.

SCREAMING

I heard on the radio there were weather warnings

but living in the south you brush them off.

When it started to

get 150, 100 yards near me,

I knew it was coming towards me.

Lauren's commute was cut short.

- Oh, my God. - Something terrifying was coming right for her.

You could hear the rocks hitting my car.

About ten seconds after that, that's when it hit me.

LAUREN SCREAMS

I stood no chance, at all.

Lauren had found herself in the path of a spinning vortex.

But unlike the water spout that Kevin encountered,

this thing was much more dangerous.

I threw my car in reverse...

..and did a 180.

I put my foot all the way down and tried to get

out of there as fast as I could.

I just remember closing my eyes.

SCREAMING

It pushed me into a building and sucked me back out.

Unlike Kevin, Lauren wasn't left smiling.

This vortex ripped her car from the ground, spinning it skyward.

I thought I was going to die.

I look around and see all the damage that it did, not only to my car

but to everything else.

'So where had all this power come from?'

Well, it was a hot day in Alabama

and the clouds forming over Lauren's head were much bigger.

And bigger clouds mean bigger vortexes.

Just like waterspouts, it's all about hot air.

The hot ground heats the air, sending it skywards.

Then winds at different altitudes

blowing at different speeds make the column of hot air spin.

As the column rises higher, it spins faster

and faster and becomes more powerful.

Now it's a tornado spinning at up to 300mph.

Giving it, as footage from this Indiana high school proves,

the power to destroy everything in its path.

Tornados are classified by how powerful they are

and how much destruction they do.

And they range from an EF-0 tornado, which is a very light,

weak tornado...

..right up to EF-5, which is a very destructive storm that can

blow over trees,

knock down houses, even pick up cars and move them some distance.

Lauren had survived a first-hand encounter with an EF-5 tornado.

She was very lucky to make it out alive.

Don't mess with Mother Nature because she is mean sometimes.

Lauren had gone head-to-head with a meteorological monster

and lived to tell the tale, but the tornado has an altogether

stranger cousin that leaves no survivors.

The Australian outback.

One of the most extreme environments on the planet.

Temperatures here can soar to 40 Celsius.

And the parched bush is like tinder to a flame.

Wildfires are a force to be reckoned with.

But from the belly of the fire comes an altogether different beast.

It's only been captured on film a few times.

But it's utterly spectacular.

The firenado.

A swirling vortex of fire reaching high into the sky.

These things may look like a special effect,

but they're not, they're very real, they're very powerful

and they're very dangerous.

And the weirdest thing about them, notice there are no clouds.

There's no storm.

A firenado doesn't need outside help to wreak havoc.

You see, the fire generates very hot air,

rising in a column that starts to spin.

It produces its own tornado.

And then you get this strange, spinning, raging, fiery hybrid.

The vortex sucks flames from the wildfire below.

And combustible gases from the air all around it...

..creating a jet engine-like inferno

with a core that can reach over 1,000 degrees Celsius.

Experts studying a bush fire in Australia

found a 25-kilometre strip of torched earth,

tracing the path of just one of these fiery beasts.

We might have given it a Hollywood name

but the firenado is a weird weather phenomena

not to be trifled with.

Fire is one of the most devastating forces on earth

and fighting it is a real challenge.

So what have we got at our disposal?

Well, we've got sand - plenty of that around here,

or we've got CO2, water, foam...

But in Virginia, USA, two engineering students have come up

with an extraordinary, new flame extinguishing solution.

A patented design that they hope will reinvent firefighting.

The first time that we were able to show it to the fire marshals -

these people that see fire every day -

they see it going out instantly, they are like,

"Wow! What is this? Why do we not use this?"

MACHINE HUMS

The concept itself is not new

but nothing practical has ever come about.

Nothing that can really be used.

We know how devastating fire can be,

but putting it out is just as dangerous.

The problem is that different substances burn in different ways,

which means that when it comes to extinguishing them,

you need to use different methods.

and if you get it wrong, it can be disastrous.

Like throwing water on a burning chip fat fryer in the kitchen.

So Seth and Viet saw a gap in the market for a simple solution.

A lot of people freak out and throw water on it.

That's the worst thing you could do for a grease fire.

We designed it to work on liquid fires and things of that nature.

But this wasn't to be your average extinguisher.

Seth and Viet had something more unusual in mind.

An idea so outlandish that, at first, well,

everyone thought they were a bit mad.

The person that leads the class, he's telling us, you know,

you guys should know if it doesn't work,

you've put yourselves at risk of failing the class.

With their engineering degrees on the line,

Seth and Viet still dared to dream.

It came down to this technology is going to happen one day.

Why not us be the ones to create it?

Seth and Viet weren't working on a miraculous powder

or some sort of fire dampening fluid.

No. They believed that an invisible force could be

channeled to extinguish the flames.

They'd made...

..the world's first...

MACHINE HUMS

..sound extinguisher.

This is the first time that a device like this has actually been put into practice.

MACHINE HUMS

But how does it work?

Well, this sound generating, flame-busting, backpack

is based on some very simple science.

For a fire to burn, it needs both fuel and oxygen.

If you take one of these away, it simply can't burn any more.

Seth and Viet realised that you could use sound to split these elements.

WHISTLING SOUND

This should make things clearer.

So we know that sound moves in waves.

Send sound waves through a gas-filled tube,

light it,

and you can clearly see the wave pattern.

Changing the volume and frequency of sound

changes the shape of the wave.

What the guys had realised is that specific frequencies of sound waves,

combined together,

could separate the oxygen from the fuel,

thus extinguishing the flames.

This is just the start for the sound extinguisher.

MACHINE HUMS

It has potential far beyond the kitchen.

It would be awesome to see this being applied,

just attached to drones and swarms of them attacking a forest fire,

building fires - that'd be really cool to see.

Putting human life out of harm's way.

Engineering is all about finding a way to make the impossible, possible. So that's what we did.

So, in the future, we might be fighting fire with big beats

instead of water hoses.

But in the meantime, if you hear the roar of wind

and see a spinning vortex spewing flames...

..hurtling over land,

or whipping up water...

- ..don't do a Kevin. - Ha-ha, ha!

Argh!

Stay out of its way.

All very curious and strange stuff.

But I can assure you there's a bit more weirdery to come yet.

Next time...

How does a lake form at the bottom of the ocean?

Does money really grow on trees?

How does a kingfisher help design a super-fast train?

And could robot swarms cure cancer?